B. Modern Approaches
Humanistic Approach
What was Donna says that one reason FIGHT AUTISM. . . . I WILL CONTROL IT. . . .
she wrote her books was to IT WILL NOT CONTROL ME” (D. Williams,
Donna’s escape her prison of autism. 1994, p. 238).
potential? Autism has trapped her in a Humanists believe that, like Donna, we may
world where she sometimes have to struggle to reach our potential, but we
blinks compulsively, switches lights on and off have control of our fate and are free to become
for long periods of time, rocks back and forth, whatever we are capable of being. e humanistic
freezes up, stares off into space without being approach emphasizes the positive side of human
able to stop herself, hates to be touched, cannot nature, its creative tendencies, and its inclina-
stand to enter public places, and hates to make tion to build caring relationships. is concept of
eye contact with others (D. Williams, 1992). human nature—freedom, potential, creativity—
Even though Donna has serious life challeng- is the most distinctive feature of the humanistic
es, she strives toward reaching her potential, and approach and sets it far apart from the behavioral
her achievements are impressive. She has pub- and psychoanalytic approaches (Giorgi, 2005).
lished autobiographies and textbooks on autism. The humanistic approach officially began in
Her creative paintings and sculptures can be seen the early 1960s with the publication of the Jour-
at exhibits. Donna is also a singer–songwriter nal of Humanistic Psychology. One of the major Photo Credit: center, Jacket cover from Somebody Somewhere by Donna Williams. Used by permission of Times Books, a division of Random House, Inc.
who has released two incredible albums. Also, Although the majority of people with figures behind establishing the journal and the
she married a man she refers to as a “diamond of autism have difficulty with language, humanistic approach was Abraham Maslow,
Donna has an amazing ability for
written and spoken language.
a person” (D. Williams, 2009). who had become dissatisfied with the behavioral
Donna’s struggle to free herself from autism, and psychoanalytic approaches. To paraphrase
develop close personal relationships, and reach her potential char- Maslow (1968), the humanistic approach was to be a new way of
acterizes the humanistic approach. perceiving and thinking about the individual’s capacity, freedom,
The humanistic approach emphasizes that each individual has great and potential for growth. Many of humanism’s ideas have been
freedom in directing his or her future, a large capacity for achieving per- incorporated into approaches for counseling and psychotherapy.
sonal growth, a considerable amount of intrinsic worth, and enormous Because of its free-will concept of human nature and lack of
potential for self-fulfillment. experimental methods, many behaviorists regard the human-
Donna echoes the humanistic approach when she writes, istic approach as more of a philosophy of life than a science of
“Autism tried to rob me of life, of friendship, of caring, of shar- human behavior.
ing, of showing interest, of using my intelligence . . . it tries e humanistic approach also applies to dealing with a student’s
to bury me alive. . . .” The last words in her book are “I CAN problems, such as test anxiety and procrastination.
Humanistic Approach to Test Anxiety
How can e first year of college can be a diffi- Psychologists have also studied students whose academic per-
cult adjustment for many students, formance ranged from poor to very good in order to develop a pro-
students reach since it is more demanding and stress- file of a successful student. Studies showed that successful students
share a number of similar characteristics: they feel competent about
their potentials? ful than high school. Researchers
wanted to learn which specific meeting the demands of their classes; they believe
factors lead to high academic performance and successful they can handle test situations; they are very good
adjustment among first-year college students. They at organizing their study time and leisure time;
found that students who were confident in their aca- they prepare themselves for tests and do not
demic abilities performed significantly better than procrastinate (Kleijn et al., 1994).
students who were less confident, and they adjusted Based on studies of students’ performances,
better to college. Also, students who had higher expec- the humanistic approach would say that just as
tations for academic success, such as performing well successful students found ways to reach their
in courses, received better grades (Chemers et al., academic potential, all students should search
2001). Based on these findings, it is evident that believ- for ways to reach their own potentials. The
ing in one’s abilities and potential is an important fac- humanistic approach emphasizes that students
tor in being a successful student. ese results may be have the capacity to choose, that each is unique
useful for educators in helping students who do poorly or special, and that students should have
in school to not give up but rather try to develop their faith in their personal or subjective feelings
academic potential. (Hansen, 2000).
10 M O D U L E 1 D I S C O V E R I N G P S Y C H O L O G Y
PowerStudy 4.5™
Module 10
Cross-Cultural Approach I. Application: Behavior
Autism is believed to exist South Korea. The number of people with Modification
in every culture (Grinker
How is autism 2007). Let’s look at how dif- autism in South Korea is unknown, as the dis-
perceived in other order has a terrible stigma and children with
cultures? ferent cultures perceive autism are o en kept at home hidden from the
autism. public. Parents in South Korea may fear that their
United States. A psychologist in family will lose face if people know someone with autism lives there and
the United States first described the that marriage prospects for their other children will be negatively affected
symptoms of autism almost 70 years as a result of having a child with an abnormality.
ago (L. Kanner, 1943). Then autism Physicians in South Korea usually diagnose what would be considered
was thought to be caused by environmental factors, autism in the United States as reactive attachment disorder (see p. 377),
such as having “cold” parents. In the 1960s, the focus which they interpret as “lack of love.” is is a less stigmatizing diagnosis,
changed to searching for biological causes (Rimland, 1964). as parents believe they can help their child by providing more love. Also,
Today, researchers believe the probable causes of autism it doesn’t negatively harm the family as much as a genetic disease might.
include environmental and genetic factors (C. Kalb, 2008; e unfortunate result, however, is that children with autism do not get
Kra , 2006). the treatment they need. Within only the past few years, the perceptions
ere are between 1 million and 1.5 million Americans of autism have begun to positively change in South Korea. Some children
with autism (ASA, 2008). Early diagnosis is a priority in the with autism are now going to school and even walking out in public with
United States. While the diagnosis of autism usually occurs their families (Grinker, 2007).
between ages 2 and 3, the American Academy of Pediat- e differences in how autism is perceived in the United States and South
rics (2007) is now recommending screening as early as 18 Korea show the influence of cultural factors and the use of the cross-cultural
months, recognizing the importance of early intervention. approach in psychology (Matsumoto & Juang, 2008; Shiraev & Levy, 2009).
Treatment is provided by psychiatrists and other physi- The cross-cultural approach studies the influence of cultural and ethnic simi-
cians, psychologists, teachers, speech therapists, play thera- larities and differences on psychological and social functioning.
pists, and other professionals who understand autism. ere are also differences in how other cultures experience test anxiety.
Cross-Cultural Approach to Test Anxiety
How do other Culture plays an important role parents are less involved with their children’s school-
in determining the intensity work and they promote independence and personal
cultures deal with and expression of test anxiety, responsibility. A related cross-cultural difference is
test anxiety? and test anxiety has been how children express test anxiety. Indian students
examined in countries across express their anxiety through physical symptoms,
the globe (Bodas & Ollendick, 2005). whereas American students experience more
The development and severity of test anxiety appear cognitive symptoms, such as excessive worrying
to be different between Asian and non-Asian students. This symbol indicates a (Bodas & Ollendick, 2005; Verma et al., 2002).
For example, students in India experience heightened test cultural diversity topic.
This research shows how the cross-cultural
anxiety due to several factors, including the cultural emphasis on approach provides different and interesting answers to the same
academic achievement, parental and social pressures to perform, question (Shiraev & Levy, 2009). In each module, we will high-
and the stressful, competitive nature of exams. In contrast, Ameri- light a cross-cultural study, which will be indicated by the cultural
can students don’t experience as much test anxiety, in part because diversity symbol shown above.
Evolutionary Approach Eclectic Approach
e most recent modern approach to psychology Rather than strictly focusing on one of the seven approaches,
emerges out of evolutionary theory and is called most of today’s psychologists use an eclectic approach, which
the evolutionary approach. means they use different approaches to study the same behavior. By
combining information from the biological, cognitive, behav-
The evolutionary approach studies how evolu- ioral, psychoanalytic, humanistic, cross-cultural, and evolu-
tionary ideas, such as adaptation and natural selec- tionary approaches, psychologists stand a better chance of
reaching their four goals of describing, explaining, predicting,
tion, explain human behaviors and mental processes. and controlling behavior.
Although the evolutionary approach is rela-
We have discussed the approaches used by modern psychol-
tively new, research has already examined how ogists so you can compare them with the different approaches
evolution influences a variety of behaviors and mental processes, such used by early psychologists. As you compare early and mod-
as aggression, mate selection, fears, depression, and decision making ern approaches, you can appreciate how much psychology has
(Buss, 2004, 2007, 2009). We’ll discuss the evolutionary approach again changed in the past 100 years.
in Module 4 (p. 69) and include some of the exciting research resulting
from this approach throughout the text.
B . M O D E R N A P P R O A C H E S 11
C. Historical Approaches
How did Imagine living in the late 1800s and early 1900s, when the electric light, radio, and airplane were being invented
psychology and the average human life span was about 30 years. is was the time when psychology broke away from philoso-
phy and became a separate field of study. As they developed this new area, early psychologists hotly debated its
begin? definition, approach, and goals (Benjamin, 2000). We’ll highlight those early psychologists whose ideas and criti-
cisms shaped the field. We’ll begin with the person considered to be the father of psychology, Wilhelm Wundt.
Structuralism: Elements of the Mind Functionalism: Functions of the Mind
There were no bands or celebrations For twelve years, William James labored
Who when Wilhelm Wundt established the Who wrote over a book called e Principles of Psy-
established first psychology laboratory in 1879, in the first chology, which was published in 1890 and
the first lab? Leipzig, Germany. In fact, his laboratory textbook? included almost every topic that is now
was housed in several rooms in a shabby part of psychology textbooks: learning,
building that contained rather simple sensation, memory, reasoning, attention,
equipment, such as platforms, various feelings, consciousness, and a revolution-
balls, telegraph keys, and metronomes. ary theory of emotions.
e heavily bearded Wundt, now consid- For example, why do you feel fear when
ered the father of psychology, would ask running from a raging wolf? You might
subjects to drop balls from a platform or answer that an angry wolf (figure below)
listen to a metronome (figure below) and is a terrifying creature that causes fear
report their own sensations. Wundt and and makes you run—fear makes you run.
his followers were analyzing their sensa- Not so, according to James, who reasoned
tions, which they thought were the key to that the act of running causes a specific
analyzing the structure of the mind (Her- set of physiological responses that your
Wilhelm Wundt genhahn, 2009). For this reason they were William James brain interprets as fear—running makes
1832–1920 called structuralists and their approach 1842–1910 you afraid. According to James, emotions
was called structuralism. were caused by physiological changes; thus, running produced
Structuralism was the study of the most basic elements, primarily sen- fear. You’ll find out if James’s theory of emotions was correct in
sations and perceptions, that make up our conscious mental experiences. Module 16.
Just as you might assemble hundreds of pieces of a jigsaw puz- Unlike Wundt, who saw mental activities as composed of basic
zle into a completed picture, structuralists tried to combine hun- elements, James viewed mental activities as having developed
dreds of sensations into a complete conscious experience. Perhaps through ages of evolution because of their adaptive functions,
Wundt’s greatest contribution was his method of introspection. such as helping humans survive. James was interested in the
Introspection was a method of exploring conscious mental process- goals, purposes, and functions of the mind, an approach called
es by asking subjects to look inward and report their sensations and functionalism.
perceptions. Functionalism, which was the study of the function rather than the
For example, after listening to a beating metronome, the structure of consciousness, was interested in how
subjects would be asked to report whether their sensations were our minds adapt to our changing environment.
pleasant, unpleasant, exciting, or relaxing. However, Functionalism did not last as a unique
introspection was heavily criticized for being an approach, but many of James’s ideas grew
unscientific method because it was solely into current areas of study, such as emotions,
dependent on subjects’ self-reports, which attention, and memory (Hergenhahn, 2009).
could be biased, rather than on objective In addition, James suggested ways to apply
measurements. Although Wundt’s approach psychological principles to teaching, which
was the first, it had little impact on modern psy- had a great impact on educational psychol-
chology. e modern-day cognitive approach ogy. For all these reasons, James is considered
also studies mental processes, but with differ- the father of modern psychology.
ent scientific methods and much broader inter-
ests than those of Wundt. Notice that James disagreed with Wun- Does running from an
It wasn’t long before Wundt’s approach was dt’s structural approach and pushed psy- angry wolf cause fear?
criticized for being too narrow and subjective Can you describe chology toward looking at how the mind
in primarily studying sensations. ese criti- each sensation functions and adapts to our ever-changing world. About the same
cisms resulted in another new approach, called you hear? time that James was criticizing Wundt’s structuralism, another
group also found reasons to disagree with Wundt; this group was
functionalism. the Gestalt psychologists.
12 M O D U L E 1 D I S C O V E R I N G P S Y C H O L O G Y
PowerStudy 4.5™
Gestalt Approach: Behaviorism: Module 10
Sensations Versus Perceptions Observable Behaviors A. Operant Conditioning
Who said, When you see a road hazard sign like the one in Who “Give me a dozen healthy infants,
the photo below, you think the lights forming offered a well-formed, and my own special
“Wundt is the arrow are actually moving in one direction. world to bring them up in and I’ll
wrong”? This motion, however, is only an illusion; the guarantee? guarantee to take any one at ran-
lights are stationary and are only flashing on dom and train him to become any
and off. type of specialist I might select—
The illusion that flashing lights appear to doctor, lawyer, artist . . .” (Watson,
move was first studied in 1912 by three psy- 1924).
chologists: Max Wertheimer, Wolfgang Köhler, ese words come from John B.
and Kurt Koffka. They reported that they had Watson, who published a landmark
created the perception of movement by briefly paper in 1913 titled “Psychology
flashing one light and then, a short time later, a as a Behaviorist Views It.” In it, he
second light. Although the two bulbs were fixed, rejected Wundt’s structuralism and
the light actually appeared to move from one to its study of mental elements and
the other. ey called this the phi phenomenon; conscious processes. He rejected
today it is known as apparent motion. introspection as a psychological
Wertheimer and his colleagues believed that technique because its results could
Max Wertheimer the perception of apparent motion could not be John B. Watson not be scientifically verified by other
1883–1943 1878–1958
explained by the structuralists, who said that psychologists. Instead, John Watson
the movement resulted from simply adding together the sensations from boldly stated that psychology should be considered an objec-
two fixed lights. Instead, Wertheimer argued that perceptual experiences, tive, experimental science, whose goal should be the analysis
such as perceiving moving lights, result- of observable behaviors and the prediction and control of
ed from analyzing a “whole pattern,” or, those behaviors (Harzem, 2004). It is a small step from these
in German, a Gestalt. ideas to Watson’s boast, “Give me a dozen
The Gestalt approach emphasized that healthy infants . . . ,” which illustrates the Can anyone
behavioral approach. guarantee what
perception is more than the sum of its parts I will become?
The behavioral approach emphasized the
and studied how sensations are assembled
into meaningful perceptual experiences. objective, scientific analysis of observable
In our example, Gestalt psychologists behaviors.
would explain that your experience of From the 1920s to the 1960s, behav-
perceiving moving traffic lights is much iorism was the dominant force in
more than and very different from what American psychology. Part of this
is actually happening—fixed lights dominance was due to the work of
flashing in sequence. These kinds of B. F. Skinner and other behaviorists,
Photo Credits: right, © Image Source Black/Alamy; left, © Tony Freeman/PhotoEdit findings could not be explained by the who expanded and developed Watson’s
structuralists and pointed out the limi- Why do blinking lights ideas into the modern-day behavioral
tations of their approach (D. P. Schultz seem to move? approach, which is fully discussed in
& Schultz, 2008). Module 10. However, beginning in the 1970s and continuing
After all these years, many principles of the Gestalt approach are into the present, behaviorism’s dominance was challenged
still used to explain how we perceive objects. We’ll discuss many of the by the cognitive approach, whose popularity now surpasses
Gestalt principles of perception in Module 6. behaviorism (Evans, 1999; Glassman & Hadad, 2004).
Survival of Approaches
Which e survival of each approach—structur- disagreed with Watson’s strict behavioral approach and developed
alism, functionalism, Gestalt, and behav- largely in parallel with these other approaches. These disagree-
approaches iorism—depended on its ability to survive ments in approaches resulted in heated debates among early psy-
chologists, but they helped psychology develop into the scientific
survived? its criticisms. Criticisms of Wundt’s struc- field it is today (Evans, 1999).
tural approach gave rise to the functional Although early American psychologists differed in their
approach of James and the Gestalt approach of Wertheimer, Köhler, approaches, they shared one underlying theme that was a sign of
and Ko a. Criticisms of all three approaches—structural, func- their times. ey discriminated against women and minorities in
tional, and Gestalt—gave rise to Watson’s behavioral approach. both academic and career settings. Such discriminatory practices
Another approach, Sigmund Freud’s psychoanalytic approach (see were widespread in early times, and we’ll examine that issue next.
p. 9), which emphasized the influence of unconscious processes,
C . H I S T O R I C A L A P P R O A C H E S 13
D. Cultural Diversity: Early Discrimination
Because psychologists focus on studying and understanding human that were operating at the time. is means that, for the first 75 of its
behavior, you would expect them to be among the first to recognize more than 100 years of existence, the academic policies and career
the mistreatment of and discrimination against other groups. How- opportunities of American psychology were determined by White
ever, psychologists are human and, being human, they knowingly or males, who both intentionally and unintentionally discriminated
unknowingly adopted and carried out the discriminatory practices against women and people of color. Here are just a few examples.
Women in Psychology
Why couldn’t e reason Mary Calkins (below) could Even a er women began obtaining doctorates, the only posi-
not enter graduate school was that tions open to them were teaching jobs at women’s col-
she enter she was a woman, and many uni- leges or normal schools, which trained high school
graduate school? versities (Johns Hopkins, Har- teachers (Furumoto & Scarborough, 1986). During
vard, Columbia) would not the past 35 years, women have made great progress
admit women. Since Calkins was a faculty member and in the field. In 1970, about 20% of graduate stu-
had established a laboratory in psychology at Wellesley dents receiving PhDs were women, and by 2005,
College in 1891, she petitioned and was allowed to take the number had increased to about 70%. However,
seminars at Harvard. There, she completed all require- even though women currently earn more PhDs in Photo Credits: top, Courtesy, Margaret Clapp Library Archives, Wellesley College, photo by Patridge; bottom left and right, Archives of the History of American
ments for a PhD and was recommended for a doctorate by psychology than men, female psychologists earn Psychology, University of Akron
her professors, but the Harvard administration declined to less than male psychologists, and fewer women are
grant it because she was a woman (Furumoto, 1989). It was Mary Calkins was not editors of psychology journals (APA, 2007b; Cyn-
not until 1908 that a woman, Margaret Washburn, was given a PhD because kar, 2007). Not only did women face discrimination
awarded a PhD in psychology. in psychology, but so did people of color.
she was a woman.
Minorities in Psychology
Why so few In psychology’s early days, only a few north- During the early 1900s, few degrees were awarded to Hispan-
ern White universities accepted Black stu- ics. One exception was George Sanchez (photo below), who con-
minority dents, while all southern White universities ducted pioneering work on the cultural bias of intelligence tests
students? denied admission to Black students. given to minority students. Sanchez criticized the claim that
The first African American woman Mexican Americans were mentally inferior, saying the claim was
to receive a PhD in psychology was Inez based solely on intelligence tests. He showed that intelligence tests
Prosser (on left), who graduated from the contained many questions that were biased against minorities and
University of Cincinnati in 1933. Her career thus resulted in their lower scores (R. V. Guthrie, 1976).
was spent teaching at Black colleges and From the founding of the American Psycho-
helping Black students obtain financial aid logical Association in 1892 to 1990, its cumulative
to attend college (Benjamin, 2008). membership was 128,000. Of those members, only
Between 1920 and 1966, only 8 PhDs 700 were African American, 700 were Latino, and
in psychology were awarded to Black 70 were Native American. The numbers of eth-
students, compared to 3,767 doctor- nic minority members are rising; however, they
Inez Prosser was the ates to Whites (R. V. Guthrie, 1976). are still low (1.9% African American, 2.0% Asian
first Black woman to In 1996, 168 PhDs were awarded to American, 2.2% Latino, and 0.2% Native Ameri-
get a PhD in 1933. African Americans, 183 to Hispanics, George Sanchez found can) (APA, 2007a). Psychology must continue to
23 to Native Americans, 131 to Asians, and 2,939 to Whites intelligence tests were focus on recruiting minorities and ensuring their
(Rabasca, 2000b). culturally biased. academic and career success (Maton et al., 2006).
Righting the Wrongs
Today, people of color are still underrepre- students about careers in psychology (APA, 2009b). e APA has
sented in academic departments and in an official policy supporting equal opportunities “for persons
How much graduate programs in psychology, although regardless of race, gender, age, religion, disability, sexual orienta-
success? their numbers and influence are increasing tion and national origin” (Tomes, 2000).
(APA, 2008a). In the late 1990s, several states banned affirmative action pro-
e American Psychological Association (APA) recognized the grams, which had helped minority students enter college. As a
need to recruit more ethnic minorities and formed a special group result, university enrollments of minority students in these states
to reach this goal. e group established numerous journals to pro- dropped (J. Steinberg, 2003). Psychology departments are actively
mote the causes of women and ethnic minorities (DeAngelis, 1966) searching for ways to recruit minority students (M. R. Rogers &
and sponsored a program to visit high schools and teach minority Molina, 2006).
14 M O D U L E 1 D I S C O V E R I N G P S Y C H O L O G Y
Concept Review
1. The systematic, scientific study of 8. The approach that focuses on cultural
behaviors and mental processes is called and ethnic influences on behavior is called
the approach.
.
2. The four goals of psychology are to
(a) what organisms do,
to (b) the causes of
behavior, to (c) behavior 9. Wundt studied the elements that made up
in new situations, and to (d) behavior, which the conscious mind and called this approach
has both positive and negative aspects. (a) . Subjects were asked to
observe the workings of their minds, a tech-
nique that Wundt called (b) .
3. The approach that focuses on how Modern-day psychologists who study mental
one’s nervous system, hormones, and activities with more objective and scientific
genes interact with the environment is methods are said to use the (c)
called the approach. approach.
Photo Credits: (#1) Courtesy of Chris Samuel, by permission of Chris Samuel; (#3) © Dana Fineman/Vistalux; (#6) Jacket cover from Somebody Somewhere by 10. William James disagreed with Wundt’s
Donna Williams. Used by permission of Times Books, a division of Random House, Inc.; (#10) © Tony Freeman/PhotoEdit; (# 11) © Image Source Black/Alamy structuralism and instead emphasized the
4. The approach that studies how people think, functions, goals, and purposes of the mind and
solve problems, and process information is
called the approach. its adaptation to the environment; he called
this approach (a) . James also
applied the principles of psychology to teach-
ing, so his approach had a great effect on the
5. The approach that analyzes how environ- field of (b) psychology.
mental rewards and punishments shape,
change, or motivate behavior is called the 11. Some psychologists disagreed with
approach.
Wundt’s approach of structuralism and
instead believed that perceptions are
6. The approach that stresses the influence more than the sum of many individual
of unconscious feelings, fears, or desires on (a) . These psychol-
the development of behavior, personality, ogists called their approach the
and psychological problems is called the (b) approach, which
(a) approach. This approach studied how sensations were assembled
also emphasizes the importance of early into meaningful (c) .
(b) experiences.
7. The approach that emphasizes freedom of 12. John Watson disagreed with
choice, self-fulfillment, and attaining one’s Wundt’s approach, which was called
potential is called the (a) (a) , and disagreed with
approach. Many of this approach’s concepts Wundt’s technique of studying the mind,
have been taken up and used in which was called (b) .
(b) . Instead, Watson emphasized the objective,
scientific analysis of observable behaviors,
which was known as the (c)
approach. Later, this approach became a
dominant force in psychology through the
work of behaviorist (d) .
Answers: 1. psychology; 2. (a) describe, (b) explain, (c) predict, (d) control; 3. biological; 4. cognitive; 5. behavioral; 6. (a) psychoanalytic,
(b) childhood; 7. (a) humanistic, (b) counseling or psychotherapy; 8. cross-cultural; 9. (a) structuralism, (b) introspection, (c) cognitive; 10. (a) func-
tionalism, (b) educational; 11. (a) sensations, (b) Gestalt, (c) perceptions; 12. (a) structuralism, (b) introspection, (c) behavioral, (d) B. F. Skinner
C O N C E P T R E V I E W 15
E. Research Focus: Taking Class Notes
Best Strategy for Taking Class Notes?
How good As you listen to lectures in class, you’ll probably be taking notes. But how
do you know if you’re using the best system or strategy? To research some
are your particular behavior, such as note-taking, psychologists first ask a very
class notes? specific research question: Which system or strategy for taking notes
results in the best performance on tests? One researcher answered this
question by using a combination of behavioral and cognitive approaches (A. King, 1992).
As we describe this interesting study, notice how it involves the four goals of psychology,
beginning with the first goal, describing behavior.
1st Goal: Describe Behavior
e researcher divided college students into three different groups. Each group was given a
different method or strategy for taking notes. As described below, students practiced three dif-
ferent strategies for taking notes: review notes, summarize notes, and answer questions about notes.
A. Review Notes B. Summarize Notes C. Answer Questions about Notes
e strategy that Students took notes as usual but, a er the Students took notes as usual but, a er the lecture, used
lecture, used their notes to write a summa- their notes to ask and answer questions about the lecture
most students use is ry of the lecture in their own words. material. Students were given a set of 13 general ques-
to try to write down tions, such as: What is the main idea of . . . ? How would
as much as possible Students were shown how to identify a you use . . . to . . . ? What is a new example of . . . ? What
of what the professor main topic and, in their own words, write is the difference between . . . and . . . ? Students answered
says. en, before a sentence about it. en they identified a each of these questions using their class notes.
exams, students subtopic and wrote a sentence that related
review their notes, it to the main topic. When linked together, A er practicing one of these three note-taking strate-
hoping they took these sentences created a summary of the gies, students watched a videotaped lecture and used
good class notes. lecture, written in the students’ own words. their particular strategy for taking notes.
2nd Goal: Explain Behavior Note-Taking Strategy & Average Exam Score
A week a er each group had watched a videotaped lecture, they were given an
exam. e graph on the right shows that the group who used the strategy of tak- Review notes 34
ing notes plus answering questions scored significantly higher than the other Summarize notes 45
two groups. e researcher explained that students who took notes and then Answer questions 51
answered questions about their notes retained more information than students
who employed the other two strategies (A. King, 1992).
3rd Goal: Predict Behavior 4th Goal: Control Behavior Purpose of the Research Focus
On the basis of these results, Students can increase their chances of is study shows how psychologists
the researcher predicts that getting better grades by taking the time
students who use the strategy to learn a better note-taking strategy. answered a very practical and impor-
that combines note-taking tant question about how best to take
with answering questions are is new strategy involves taking notes lecture notes. We’ll use the Research
likely to retain more infor- and then answering, in their own words, Focus to show how psychologists use
mation and perform better a series of general questions about the different approaches and research tech-
on exams than students who lecture material. Although this new niques to answer a variety of interesting
use traditional note-taking note-taking strategy takes a little time questions about human behavior.
methods, such as writing as to learn, the payoff will be better perfor-
much as they can and then mance on exams. is and other Each time you see this symbol, it will indicate a
reviewing their notes before research show the connection between Research Focus, which occurs in each module.
exams. good note-taking skills and higher test
performance (Peverly et al., 2003). Although a large percentage of psychologists engage in
research, you’ll see next how many others work in a variety
of career settings that may or may not involve research.
16 M O D U L E 1 D I S C O V E R I N G P S Y C H O L O G Y
F. Careers in Psychology
Psychologist Versus Psychiatrist
What’s a Many students think A clinical psychologist has a PhD, PsyD, or EdD, has special-
psychologist? psychologists are pri- ized in a clinical subarea, and has spent an additional year in a
marily counselors and
therapists, even though supervised therapy setting to gain experience in diagnosing and
degrees in psychology are awarded in many
areas. Obtaining an advanced degree in psy- treating a wide range of abnormal behaviors.
chology requires that one finish college Similar to clinical psychologists are counseling psy-
and spend two to three years in postgrad-
uate study to obtain a master’s degree or chologists, who provide similar services but usually work
four to five years in postgraduate study with different problems, such as those involving marriage,
to obtain a PhD. Some careers or work family, or career counseling.
settings require a master’s degree, while
others require a PhD. Many students are Until recently no psychologists in the United States
confused about the difference between a have been able to prescribe drugs. Now, psychologists
psychologist, a clinical or counseling in New Mexico and Louisiana who complete special
psychologist, and a psychiatrist. medical training can prescribe drugs as psychiatrists do.
A psychologist is usually someone who Several other states may pass similar legislation in the
Figure/Text Credit: Pie chart data from “Psychological Science Around the World,” by M. R. Rosenzweig, 1992, American Psychologist, 47, 718–22. near future, giving psychologists the right to prescribe
has completed 4 to 5 years of postgraduate It usually takes about 4 to 5 years after medication (Munsey, 2008a, 2008b).
education and has obtained a PhD, PsyD, or college to become a psychologist.
EdD in psychology. A psychiatrist is a medical doctor (MD) who has spent sev-
eral years in clinical training, which includes diagnosing possible
physical and neurological causes of abnormal behaviors and
treating these behaviors, often with prescription drugs.
Psychologists can work in the following career settings.
Many Career Settings 49% e largest percentage (49%) of psychologists work as clinical or counseling psycholo-
gists in either a private practice or therapy setting, such as a psychological or psychiatric clinic; a
Are psychologists mental health center; a psychiatric, drug, or rehabilitation ward of a hospital; or a private office.
usually therapists? e duties of clinical or counseling psychologists might involve doing individ-
ual or group therapy; helping patients with problems involving drugs,
As you can see in the pie chart below, stress, weight, family, or career; or testing patients for psychologi-
the majority (49%) of psychologists cal problems that developed from some neurological problem.
are therapists, while the rest work in 28%
four other settings. In the United 28% e second largest percentage (28%) of psycholo-
States and Canada, most psy-
chologists have a PhD, PsyD, or gists work in the academic settings of universities and
EdD, which requires four to colleges. Academic psychologists o en engage in some
five years of study a er college. 49% combination of classroom teaching, mentoring or helping
In many other countries, most students, and doing research in their areas of interest.
psychologists have a college
degree, which requires four to 13% e third largest percentage (13%) of psychologists
five years of study after high 13% work in a variety of other kinds of jobs and career settings.
school (Helmes & Pachana,
2005). Since the 1950s, there has 6% e fourth largest percentage (6%) of psychologists
been an increase in psychologists 6% work in industrial settings, such as businesses, corporations,
who provide therapy/health services and consulting firms. ese psychologists, o en called industrial/
and a decline in those who work in organizational psychologists, may work at selecting personnel,
academic/research settings. 4% increasing production, or improving job satisfaction.
The U.S. Department of Labor 4% e smallest percentage (4%) work in secondary schools and other
predicts that employment opportuni- settings. For example, school psychologists conduct academic and career testing and provide
ties for psychologists will grow much counseling for a variety of psychological problems (learning disabilities, attention-deficit/
faster than the average for other hyperactivity disorder).
occupations in the coming years
(U.S. Dept. of Labor, 2006). Here’s a If you are thinking of entering the field of psychology today, you have a wide and exciting
breakdown of where psychologists range of career choices. Your career choices are almost limitless! For example, in addition to the
in the United States currently work many work settings discussed above, psychologists are working in the Department of Defense,
(D. Smith, 2002). Department of Homeland Security, and National Institutes of Health. ey are also working with
attorneys, engineers, physicians, and computer scientists (DeAngelis, 2008). For those who decide
to engage in research, we’ll next discuss popular research areas that psychologists choose.
F. C A R E E R S I N P S Y C H O L O G Y 17
G. Research Areas
Areas of Specialization
As you proceed through your introductory psychology course, you’ll find that the world of psychology has been
divided into at least eight general areas. And, if you go on and enter graduate school in psychology, you’ll be expected
Which to specialize in one of these areas. Students o en find it difficult to choose only one special area of psychology, since
area should they may be interested in two or three. e reason graduate students are asked to choose one area is that there is such
an enormous amount of information that it takes great effort to master even one area. As you read about each
I choose?
research area, think about which one you might prefer.
Clinical/Counseling Developmental Photo Credits: top right, © Andy Sacks/Getty Images; top left, © Zigy Kaluzny/Getty Images; bottom right, © Frans Lanting/Corbis; bottom left, © Oleksiy
Maksymenko/Alamy
Which type of therapy is most effective? Why do some babies cry more than others?
How do people develop phobias? What happens to our sex drive
as we age?
You would be asking these
kinds of questions if you were You would be asking
a clinical or counseling these kinds of ques-
psychologist. tions if you were a
developmental
Clinical and counseling psychologist.
psychology includes the assess-
ment and treatment of people Developmental
with psychological problems, pschology examines
such as grief, anxiety, or stress. moral, social, emotion-
al, and cognitive devel-
Some clinical and coun- opment throughout a
seling psychologists work person’s entire life.
with a variety of populations, Some developmental psychologists focus on changes in infancy
whereas others may special- and childhood, while others trace changes through adolescence,
ize in specific groups like adulthood, and old age. ey work in academic settings and may
children or the elderly. ey may work in hospitals, community consult on day care or programs for the aging.
health centers, private practice, or academic settings.
Social Experimental
How does being in a group affect one’s behavior? Why does an animal press a bar to obtain food?
How can people make a good impression on others? Can learning principles be used to discipline children?
ese kinds of ques- ese kinds of ques-
tions interest social tions interest experi-
psychologists. mental psychologists.
Social psychology Experimental psy-
involves the study of chology includes the
social interactions, areas of sensation, per-
stereotypes, prejudices, ception, learning, human
attitudes, conformity, performance, motivation,
group behaviors, aggres- and emotion.
sion, and attraction.
Experimental
Many social psy- psychologists conduct
chologists work in much of their research under carefully controlled laboratory
academic settings, but conditions, with both animal and human subjects. Most work in
some work in hospitals and federal agencies as consultants and academic settings, but some also work in business, industry,
in business settings as personnel managers. and government.
18 M O D U L E 1 D I S C O V E R I N G P S Y C H O L O G Y
Photo Credits: top left, © Tom Barrick, Chris Clark, SGHMS/Photo Researchers, Inc.; top right, © Odilon Dimier/PhotoAlto/Getty Images; bottom left, © Digital Vision/ Biological Psychometrics
Getty Images; bottom right, © Andersen Ross/Getty Images
How do brain cells change during Alzheimer’s disease? What do college entrance tests show?
How do genes affect your intelligence? What career best fits my abilities?
Physiological psychologists ese questions
or psychobiologists study introduce an area
the biological basis of called psychomet-
learning and memory; rics, which involves
the effects of brain the construction,
damage; the causes administration, and
of sleep and wakeful- interpretation of
ness; the basis of psychological tests.
hunger, thirst, and sex;
Psychometrics
the effects of stress on the focuses on the mea-
body; and the ways in which surement of people’s
drugs influence behavior. abilities, skills, intelligence, personality, and abnormal behaviors.
Biological psychology or psychobiology involves research on the To accomplish their goals, psychologists in this area focus
physical and chemical changes that occur during stress, learning, and on developing a wide range of psychological tests, which must
emotions, as well as how our genetic makeup, brain, and nervous system be continually updated and checked for usefulness and cultural
interact with our environments and influence our behaviors. biases. Some of these tests are used to assess people’s skills and
Psychobiologists work in academic settings, hospitals, and abilities, as well as to predict their performance in certain careers
private research laboratories. and situations, such as college or business.
Cognitive Industrial/Organizational
What’s the best way to learn new information? How can we increase the
productivity of workers?
Do men and women think differently? How can we select employees
who will be successful?
If these questions interest
you, think about being a If you have an interest in psy-
cognitive psychologist. chology and business, you may
wish to consider becoming an
Cognitive psychology industrial/organizational
involves how we process, psychologist.
store, and retrieve infor- Industrial/organizational psy-
mation and how cognitive chology examines the relationships of
processes influence people and their work environments.
our behaviors.
ese psychologists may be
Cognitive research involved in personnel selection,
includes memory, help improve employee relationships, or increase employee job
thinking, language, satisfaction. Industrial/organizational psychologists usually work
creativity, and decision making. Earlier we discussed a relatively in businesses, industry, and academic settings.
new area that combines cognitive and biological approaches and
is called cognitive neuroscience.
Making Decisions
If you decide to become a psychologist, you counseling and testing in a school setting. You’ll also need to spe-
What should will need to make a series of decisions. The cialize in one of the eight areas described above. A er making these
I do? first is whether to obtain a master’s degree or decisions, you are on your way to an interesting and exciting career.
a PhD. e next decision involves which set- Next, we’re going to use research findings from several research
ting to work in: choosing among private practice, clinic or hospital areas, including experimental and cognitive, and give you tips on
setting, academic research and/or teaching, industry/business, or how to improve your study skills.
G . R E S E A R C H A R E A S 19
H. Application: Study Skills
Improving Study Habits
In a survey of college freshmen, only 16% judge how prepared you are for an exam is to test yourself and get
What study reported they had very good study habits feedback from answering specific questions. For instance, can you
problems do and only 24% said they were very good at list the modern approaches and define each one? Because answer-
ing specific questions is one way to judge your learning, we built
most freshmen managing their time (HRSDC, 2007). specific questions and answers into this text. You can test yourself
report? We’ll discuss ways you can improve your by answering questions in the Concept Review in each module and
study habits and time management to help in the Summary Test at the end of each module.
you be a successful college student.
Common complaint. e most common student complaint we Reducing distractions. When we ask students about their study
hear a er exams is, “I read the book and went over my notes three habits, we o en learn they listen to music, watch TV, answer phone
times and still got a C.” This com-
plaint points to the most common How do I know calls, or use the Internet while studying. ese study habits
mistake students make in studying when I’ve studied can lead to lower exam scores (Gurung, 2005). One way
for exams. Because students read the students can improve their study habits is by eliminating
material and go over their notes sev- enough to take distractions.
a test?
Time management. A common problem students have
eral times, they may have a general feeling they is managing their time. As a result, students often fall
know the material. For example, you have just behind in classes and then must cram for exams. Intense
read about the modern approaches, the histori- studying before an exam may help you pass, but your time
cal approaches, and the differences between could be much better spent. Did you know that spreading
a psychologist and psychiatrist. Having read out your studying can help you better remember informa-
this material, you may generally feel that you tion? In fact, dividing your studying into two sessions with
know it. However, researchers have discov- time between them has been shown to result in twice as
ered a startling fact: ere is almost no rela- much learning as one study session of the same length!
tionship between how well students think they know material and is is because your brain remembers information longer if it has
how well they perform on an exam (Eva et al., 2004; Tousignant & time to process what you’ve learned (Aamodt & Wang, 2008). Next,
DesMarchais, 2002). we’ll discuss another useful way to better manage your time.
Poor judges. e reason students tend to be poor judges of what
they know is that they base their judgments more on what they Remember:
generally know than on what they specifically remember (Glen-
berg et al., 1987). For example, you might generally remember the To judge how well prepared you are for an exam, ask yourself specific
modern approaches. However, on an exam you will be asked for questions about the material. You can do that by taking the tests built into
specific information, such as names and definitions. One way to
each module—Concept Review and Summary Test.
Setting Goals
To determine which of these three goals leads to more effective
What’s the Another way to better manage your study studying, researchers told three different groups of students to set
time is to set the right goals, which can vary time goals, general goals, or specific performance goals when they
best kind of from studying for a certain period of time to studied on their own. The researchers found that students who
goal to set? studying until you feel you are well prepared set specific performance goals did significantly better on the final
(Flippo & Caverly, 2000, 2009). Which of the exam than students who set time or general goals (M. Morgan,
following goals do you think would make your study time more 1985). us, if you want to improve your study skills, you should
efficient and improve your test performance? think less about the total time you study and concentrate more on
1 Set a time goal, such as studying 10 hours a reaching a specific performance goal every week. For example, the
week or more, and then keep track of your Should my goal be first week your goal might be to correctly answer 80% of the Sum-
study time during the semester. to study 10 hours mary Test questions. Once you have reached this goal, you could Photo Credit: © Hangarter/Photolibrary
aim to answer 90% of the questions correctly. Following a study
2 Set a general goal, such as a week? plan based on specific performance goals is the key to better time
management (Wolters, 2003).
trying to study hard and stay
on schedule; then, try to reach As you’ll see next, one way to motivate yourself to reach your
this goal during the semester. performance goals is to reward yourself at the right times.
3 Set a specific performance
goal, such as answering at Remember:
least 80% of the Summary
Test questions correctly for One way to make your study time more efficient is to set a specific
each module. performance goal and keep track of your progress.
20 M O D U L E 1 D I S C O V E R I N G P S Y C H O L O G Y
Rewarding Yourself Stopping Procrastination
One problem many students have is getting Some students find the task of reading
What if you and staying motivated. One reliable solu- How do you assignments, studying for exams, or writ-
reach a goal? tion is to give yourself get started? ing papers so difficult that they cannot
a reward when you bring themselves to start. If you have prob-
reach a specific goal, such as answering 80% lems with procrastinating, here are three things you should do to
of the questions correctly. e reward may be 1get started (Ariely & Wertenbroch, 2002; Blunt & Pychyl, 2000):
a special treat (such as a CD, meal, movie, or Stop thinking about the final goal—reading 30 pages or taking
time with friends) or a positive statement
(such as “I’m doing really well” or “I’m going 2two midterm exams—which may seem too overwhelming.
to get a good grade on the test”). Giving your- Break the final assignment down into smaller goals that are less
self a reward (self-reinforcement) is an effec- overwhelming and easier to accomplish. Work on the first small
tive way to improve performance (Allgood et Motivate yourself goal, and when you finish it, go on to the next small goal. Continue
al., 2000). with rewards. until you have completed all the small goals. inking about study
tasks in specific ways makes you feel like the tasks can be completed
sooner and reduces procrastination (S. M. McCrea et al., 2008).
Photo Credits: left, © Gary Conner/Photolibrary; right, © Asia Images Group/Getty Images Remember: 3Setting smaller goals is a way to think of tasks in a specific way.
Figure/Text Credit: Excuses list from “Excuses, Excuses,” by D. A. Bernstein, 1993, APS Observer, March, 1993, Vol 6, No. 2, p. 4. Copyright © 1993 by the Association Write down a realistic schedule for reaching each of your
for Psychological Sciences. Reprinted by permission of the author. Immediately after you reach a specific goal, give yourself a reward,
which will both maintain and improve your motivation.
smaller goals. is schedule should indicate the time and place for
study and what you will accomplish that day.
Taking Notes Use a variety of self-reinforcements to stay on
your daily schedule and accomplish your
Another way to improve your performance is to take great notes. specific goals.
Students generally make two kinds of mistakes in taking notes.
One is to try to write down everything the instructor says, which is Everyone procrastinates a
impossible and leads to confusing notes. e other is to mechani- little, but it becomes a problem
cally copy down terms or concepts that they do not understand but if you continually put off start-
hope to learn by memorization, which is difficult. Researchers have ing important projects that have
four suggestions for taking good notes (Armbruster, 2000, 2009): deadlines, such as exams and
papers. Take the advice of profes-
1 Write down the information in your own words. is approach sionals on stopping procrastina-
tion: get organized, set specific These 3 steps helped me
will ensure that you understand the material and will increase goals, and reward yourself (Ariely overcome procrastination!
your chances of remembering it.
& Wertenbroch, 2002).
2 Use headings or an outline format. is method will help you If you adopt these tested methods for improving your study
skills, you’ll greatly increase your chances of being a successful
better organize and remember the material. student (Flippo & Caverly, 2009).
3 Try to associate new lecture or text material with material that Remember:
you already know. It’s easier to remember new information if you One of the most effective ways to start a large assignment is to break it
can relate it to your existing knowledge. at is the reason we have down into a series of smaller goals and work on each goal separately.
paired terms in the Concept Review section with illustrations, draw-
ings, and photos that you are familiar with from earlier in the text. Unusual Excuses for Missing Exams
I can’t be at the exam because my cat is having kittens
4 As we discussed in the Research Focus (p. 16), you can improve
and I’m her coach.
your note-taking by asking yourself questions, such as: What is the I want to reschedule the final because my grandmother
main idea of . . . ? What is an example of . . . ? How is . . . related to
what we studied earlier? Writing the answers in your own words is a nun.
will give you a better chance of remembering the material (A. I can’t take the exam on Monday because my mom is
King, 1992).
getting married on Sunday and I’ll be too drunk to drive
Even though you may take great notes and set performance back to school.
goals, if you procrastinate and put off getting started, as about 70% I couldn’t be at the exam because I had to attend the
of students report doing, your best-laid plans will come to nothing funeral of my girlfriend’s dog.
(E. Hoover, 2005). We already discussed some of the reasons behind I can’t take the test Friday because my mother is having
procrastination (p. 9), and here we’ll look at ways to overcome it. a vasectomy. (D. A. Bernstein, 1993, p. 4)
Remember: H . A P P L I C A T I O N : S T U D Y S K I L L S 21
Go through your lecture notes, ask questions, and
write down answers in your own words.
Summary Test
A. Definitions & Goals 8. The approach that studies how cultural and ethnic similarities
and differences influence psychological and social functioning is
1. The broad definition of psychology called the approach.
is the systematic, scientific study
of (a) and 9. The approach that studies how evolutionary ideas, such as
adaptation and natural selection, explain human behaviors and
(b) . The term in mental processes is called the approach.
(a) refers to observable responses of
animals and humans, and the term 10. When psychologists use different approaches to study the
same behavior, they use the approach.
in (b) refers to processes that are
not directly observable, such as
thoughts, ideas, and dreams. C. Historical Approaches
2. All psychologists agree that the first three goals of 11. Considered the father of psychology,
psychology are to (a) what organisms do, to
(b) how organisms behave as they do, and to Wilhelm Wundt developed an approach
called (a) . This approach
(c) how they will respond in the future and in studied the elements of the conscious mind
different situations. Some psychologists add a fourth goal, which
is to (d) behavior and thus curb or eliminate by using a self-report technique called Photo Credits: top left, Courtesy of Chris Samuel, by permission of Chris Samuel; bottom right, Courtesy, Margaret Clapp Library Archives, Wellesley College,
(b) . Wundt’s approach photo by Patridge
psychological and social problems. was the beginning of today’s cognitive
B. Modern Approaches approach.
12. Disagreeing with Wundt’s approach,
William James said that it was important to
3. Because behavior is often so com- study functions rather than elements of the mind.
plex, psychologists study it using seven
different approaches. The approach Accordingly, James studied the functions of consciousness as well
as how mental processes continuously flow and adapt to input
that focuses on how a person’s genetic from the environment. This approach is called .
makeup, hormones, and nervous sys-
tem interact with the environment to James’s ideas contributed to the modern area of psychology and
influenced educational psychology.
influence a wide range of behaviors is
called the approach. 13. Also disagreeing with Wundt’s approach was a group of psy-
chologists, led by Wertheimer, Köhler, and Koffka, who stated that
4. The approach that studies how perceptions cannot be explained by breaking them down into
organisms learn new behaviors or change or modify existing ones
in response to influences from the environment is called the individual elements or sensations. Instead, they believed that per-
ceptions are more than the sum of individual sensations, an idea
(a) approach. There are two versions of this called the approach.
approach. One that primarily studies observable behaviors and
excludes mental events is called (b) and is best 14. Another psychologist who disagreed with Wundt’s approach
expressed by the ideas of B. F. Skinner; the other, which includes was John B. Watson. He stated that psychology should use
observable behaviors plus cognitive processes, is called the scientific principles to study only observable behaviors and not
(c) approach and is expressed by the ideas of mental events, an approach called . Watson’s
Albert Bandura and his colleagues. approach gave rise to the modern behavioral approach.
5. An approach that examines how our unconscious fears, desires, D. Cultural Diversity: Early Discrimination
and motivations influence behaviors, thoughts, and personality
and cause psychological problems is called the 15. During the first 75 of its more than 100 years of existence, the
approach. Sigmund Freud developed this approach, as well as the field of psychology discriminated against (a) and
technique of dream interpretation, to bring unconscious ideas to (b) , as indicated by the very
the surface. limited number of these individuals who
6. The approach that investigates how people attend to, store, and were granted PhDs or offered positions
process information and how this information affects learning, in major universities. During the past 25
remembering, and believing is called the or so years, the American Psychological
approach. Association, minority organizations, and
7. An approach that emphasizes people’s capacity for personal most universities and colleges have been
growth, freedom in choosing their future, and potential for self- actively recruiting minorities and helping
fulfillment is called the approach. them enter the field of psychology.
22 M O D U L E 1 D I S C O V E R I N G P S Y C H O L O G Y
E. Research Focus: Taking Class Notes psychology. Those interested in the interaction among genes, the
nervous system, and the environment choose (e)
16. Three different strategies for note- psychology. Those interested in how people process, store, and
taking were studied: note-taking plus retrieve information choose (f) psychology.
review, which means writing down Those interested in the measurement and testing of skills,
almost everything the instructor says; abilities, personality, and mental problems specialize in
note-taking plus questions, which (g) , and those interested in the relationships
means asking and answering ques- of people and their work specialize in (h)
tions about the lecture material; psychology.
and note-taking plus summary,
which means writing a summary of H. Application: Study Skills
the lecture in your own words. The note-taking strategy that
resulted in the highest exam grades involved (a) ,
and the note-taking strategy that resulted in the lowest exam 19. Another common mistake
that students make is that they
grades involved (b) . think they know the material
F. Careers in Psychology after reading the text and
reviewing their notes. A better
way to judge how prepared you
17. There are five major settings in which psychologists work and are for an exam is to ask yourself
establish careers. The largest percentage of psychologists work in specific (a)
private practice or (a) rather than to trust your judg-
settings, where they diagnose and help ment about what you think you
clients with psychological problems. know. A good way to make your
The second largest group work in study time more efficient is to set specific (b)
(b) settings, doing a and keep track of your progress. Immediately after you reach a
Photo Credits: right, © Hangarter/Photolibrary; bottom left, © Tom Barrick, Chris Clark, SGHMS/Photo Researchers, Inc. combination of teaching and research. specific performance goal, give yourself a (c) ,
The third largest group work in a which will both maintain and improve your motivation. To
(c) of settings. improve your lecture notes, try to associate new lecture material
The fourth largest group work in with what you already know, and use your notes to ask and answer
(d) settings, where they (d) in your own words. One of the most effec-
are involved in selecting personnel, increasing job satisfaction, tive ways to overcome a strong tendency to delay starting a task,
and improving worker–management relations. The smallest group known as (e) , is to stop thinking about the final
work in other settings, such as (e) , where they goal. Instead, break down a large assignment into a series of small-
do academic testing and counseling. er goals and work on each goal separately. Finally, it’s best to set a
realistic (f) in order to accomplish each of the
G. Research Areas smaller goals.
18. There are eight common sub-
areas in which psychologists
specialize. Psychologists
interested in the assess-
ment and treatment of
people with psychological Answers: 1. (a) behaviors, (b) mental processes; 2. (a) describe,
problems, such as anxiety (b) explain, (c) predict, (d) control; 3. biological; 4. (a) behavioral,
or stress, specialize in (b) strict behaviorism, (c) social learning; 5. psychoanalytic; 6. cognitive;
(a) psychology. 7. humanistic; 8. cross-cultural; 9. evolutionary; 10. eclectic; 11. (a) struc-
Those who are interested in prejudice, turalism, (b) introspection; 12. functionalism; 13. Gestalt; 14. behavior-
attitudes, and group behaviors specialize in ism; 15. (a) women, (b) minorities; 16. (a) answering questions,
(b) psychology. Those inter- (b) reviewing notes; 17. (a) therapy or clinical, (b) academic, (c) variety,
ested in social, emotional, and cognitive changes across the life (d) industrial, (e) schools; 18. (a) clinical and counseling, (b) social,
span specialize in (c) psychology. Those inter- (c) developmental, (d) experimental, (e) biological or physiological,
ested in studying sensation, perceptions, and learning, often (f) cognitive, (g) psychometrics, (h) industrial/organizational;
under laboratory conditions, specialize in (d) 19. (a) questions, (b) performance goals, (c) reward, (d) questions,
(e) procrastination, (f) schedule
S U M M A R Y T E S T 23
Critical Thinking
How Do Autistic People Think?
QUESTIONS As a young child, Temple of animals (see photo). For example, 5What social skill Photo Credit: Courtesy of Temple Grandin, Ph.D.
Grandin had a few pe- she placed herself “inside a cow’s head” does Temple have
1What three child- culiarities. She had great to see the world through its eyes. By (unlike many with
hood symptoms difficulty learning to speak doing so she realized how frightening autism) that allows her
of autism do Donna and understanding lan- it is for cattle to approach the dip vat, to put herself “inside a
(introduced on p. 3) guage, but had an incredible a deep swimming pool filled with cow’s head”?
and Temple share? eye for color and great artis- pesticide that cattle enter to rid them
tic talent. Temple didn’t of ticks and other parasites. Cattle 6 How would
2 Which of the four know how to relate with would panic while going down a steep a humanistic
goals of psycho- other children and preferred and slippery slope and then become psychologist under-
logy is illustrated by to be alone, often rocking even more frightened as they unex- stand Temple’s
Donna refusing to herself back and forth for pectedly dropped into water. To re- accomplishments?
allow anyone to hours. She was so sensitive to duce the fear cattle had of the dip vat,
touch her? touch that she refused to allow Temple used her visual way of think- ANSWERS
anyone to touch her. Temple was ing to design equipment with a less TO CRITICAL
3 Which area of unusually sensitive to sounds. steep and slippery walkway, as well as THINKING
specialization in She compared hearing the school a more comfortable way for cattle to QUESTIONS
psychology would be bell to a “dentist’s drill” (J. P. enter the water.
best able to under- Shapiro, 1996) sounding in her
stand how Temple ear. She described going through Using her unique way of thinking in
thinks in pictures? each day feeling anxious as if she pictures, Temple has become the most
were constantly “being mugged accomplished and well-known autistic
4Of the seven mod- on the New York subway” (J. P. adult in the world. She has taken the
ern approaches to Shapiro, 1996). lead in designing and advocating for
psychology, which the use of more humane equipment
should you use to Temple was diagnosed with au- with animals. Her unique understand-
study someone with tism at the age of 3, and doctors ing of animals led her to publish an in-
autism? were certain she wouldn’t ever be sightful book explaining how animals
successful. What they didn’t feel. Temple earned a doctorate degree
know is how much Temple would in animal science and is currently a
prove them wrong. Her child- university professor, a prominent au-
hood art projects provided a thor and speaker, and a consultant for
glimpse into Temple’s unique way the care and handling of livestock.
of thinking. While most of us (Adapted from Fenly, 2006; Grandin,
think in words, Temple, like 1992, 2002, 2009; J. P. Shapiro, 1996)
many others with autism, thinks
in pictures. She compares her
memory to a full-length movie in
her head that she can replay over
and over again. She can even
view the movies from different
points of view, which help her no-
tice small details that otherwise
would have been overlooked.
Temple has made remarkable
accomplishments by applying her
visual way of thinking to her love
24 M O D U L E 1 D I S C O V E R I N G P S Y C H O L O G Y
Links to Learning
Key Terms/Key People Learning Activities
academic settings, 17 Ko a, Kurt, 13 PowerStudy for Introduction PowerStudy 4.5™
apparent motion, 13 Köhler, Wolfgang, 13 to Psychology 4.5
approach, 5 palmar sweating, 6
autism, 3 phi phenomenon, 13 Use PowerStudy to complete quizzes and learning activities for Discovering
autistic savants, 3, 7 Principles of Psychology, 12 Psychology. e DVD also includes interactive versions of the Summary Test
Bandura, Albert, 8 private practice, 17 on pages 22–23 and the critical thinking questions for the article on page 24,
behavioral approach, 8, 13 procrastination, 9, 21 key terms, an outline and an abstract of the module, and an extended list of
biological approach, 6 Prosser, Inez, 14 correlated websites.
biological psychology, 19 psychiatrist, 17
Calkins, Mary, 14 psychoanalytic CengageNOW!
career settings, 17 www.cengage.com/login
clinical and counseling approach, 9 Want to maximize your online study time? Take this easy-
psychobiology, 19 to-use study system’s diagnostic pre-test and it will create a personalized study
psychology, 18 psychologist, 17 plan for you. e plan will help you identify the topics you need to understand
clinical psychologist, 17 psychology, 4 better and direct you to relevant companion online resources that are specific
cognitive approach, 7 psychometrics, 19 to this book, speeding up your review of the module.
cognitive neuroscience, 7 rewarding yourself, 21
cognitive psychology, 19 Sanchez, George, 14 Introduction to Psychology Book Companion Website
counseling savants, 3 www.cengage.com/psychology/plotnik
secondary schools, 17 Visit this book’s companion website for more resources to help you
psychologist, 17 setting goals, 20 study, including learning objectives, additional quizzes, flash cards, updated
cross-cultural approach, 11 Skinner, B. F., 8, 13 links to useful websites, and a pronunciation glossary.
developmental social cognitive
Study Guide and WebTutor
psychology, 18 approach, 8 Work through the corresponding module in your Study
eclectic approach, 11 social psychology, 18 Guide for tips on how to study effectively and for help learning the material
evolutionary approach, 11 stopping covered in the book. WebTutor (an online Study Tool accessed through your
experimental eResources account) provides an interactive version of the Study Guide.
proscrastination, 21
psychology, 18 structuralism, 12
functionalism, 12 taking notes, 16, 21
Gestalt approach, 13 test anxiety, 3
goals of psychology, 4 therapy settings, 17
humanistic approach, 10 time management, 20
industrial/organizational Watson, John, 13
Wertheimer, Max, 13
psychology, 19 Wundt, William, 12
industrial settings, 17
introspection, 12
James, William, 12
Suggested Answers to Critical Thinking By using several or all seven of the approaches, we can more
thoroughly understand someone with autism.
1. Three symptoms of autism Donna and Temple share are poor social 5. As we learned on page 6, empathy is a social skill allowing us to
relationships, sensitivity to touch and sound, and difficulty learning put ourselves in other people’s shoes and experience how they
to speak and understand language. feel. People with autism generally have difficulty expressing empa-
thy; however, Temple conveys much empathy toward cattle.
2. The four goals of psychology are describe, explain, predict, and 6. Unlike the doctors who were certain Temple would not be success-
control. Donna knows that even the lightest touch can make her ful, humanistic psychologists believe that all people have free will,
feel uncomfortable, and so she controls her discomfort by making creativity, the ability to achieve personal growth, and an enormous
it a rule to not allow anyone to touch her. potential for self-fulfillment. Humanistic psychologists would say
that by working hard and believing in her abilities, Temple was able
3. Cognitive psychology studies how we process, store, and retrieve to reach her potential.
information. One of its primary goals is to better understand how
people think. L I N K S T O L E A R N I N G 25
4. None of the approaches is necessarily better than the others.
Rather, each approach adds a different kind of information.
Psychology
2 & Science
MODULE
40
Photo Credit: © Firefly Productions/Corbis
A. Answering Questions 28 I. Application: Research Concerns
B. Surveys
C. Case Study 29 Summary Test 42
D. Cultural Diversity: Use of Placebos
E. Correlation 30 Critical Thinking 44
F. Decisions about Doing Research
G. Scientific Method: Experiment 31 Does Binge Drinking Cause Later Health Problems?
Concept Review
H. Research Focus: ADHD Controversies 32 Links to Learning 45
26 34
36
38 PowerStudy 4.5™
39 Complete Module
Introduction
Blake’s Problem Perhaps the major questions surrounding the use of Ritalin
cwgnosiLthh2nhwoe0reeaeidgWtnivt0gsiAsnwlhm”eec8oabrgrotbohe)uamieaauctsa(teanineonaasttghnihtdniidctndetnb’tlhassayhBge“sug5Ktpevrouiilpwib,ndetbla’lifrneloBodsofakrkdrfoetrrlkoroitaoaieoexlnh?funir!dkntcr’ngesBsngemoekgg.ean”ldmwe-tawtontsseoOtkardoa,scdBeelnisddtl’t.(isotw.WihoseaaysoEd”hnem,encei”di.voatt“tthacSmowoonaWhhsogaie.yaltdaaeaTpnnfcanh,ycifntesaatTotetyossBnynybohehres.ntshliltaloeciraheodontkaainedsoekrserireglixgdsno,neslliemmwyoy2necdvodtgpw)orse0iegu.obiitipassnrh0Bfbtithodpassoenh7uiel“rutyllmra3ar)etestahaf.ma.okerduyrheybstvBsem(,eeepliaete,llTlmacalhitiahrthfsnnaodrsoekaya.seeytguaemveeA’nmlfinosnlldoioadotiwlone“srtudeumcnengsri-darsat,lgxBa’oogttetshahhlsahaacus,feflodiabphrhaeolmrnamunctitroiecotaenrlosehhuarimdaeagdtsndb’edes-wns-,n,,ledolemsdedthsaatBsuwtldIiaatmekhvneaAat,,d(Dlgn4wireHoa)auwDbntsgolaaodettictcraaooegglnanleectottg5morshAe.oen2eeddlDc0ntBomei0itHstrel.a3eaonsw)Dkds.awhwtheiInesa’hWeenMAt(fshdht1ovhfftieb)cDehoauefeoeptWher’dtiuerhcdsHlerrohrlditlsoeeugeacddioaDdricbvo’valtoernmheeeluiiraiefetossoteiesl1etcwmloansrimffegdr.rsrpse,etoeoisrstIa,bhbaraRceiihfn(wirfietenrtnt3noipemosihct)BgiBnnwsauwtietotelyalhgtlsohtgaansniicleohthnakkoshptcdhoqt,tlev,elruoseyhaw’ua’eeemAosselesierndoesmmpessDpcpasrgdiy,dictayereeBnyHmsiwtrehsscowgbliusetetioDoapnnh.ceahe,agwrktscrhAeelratosslile(itiachetuybmhrlnRe’vhronseedwonoieiosnetdnoeutpeclfe,horgaho,rrclr(slilttddaswe2uuosoaae,l)p&irsrrsbdmhbsactrsguytcleheghneoeeqoRmruotneoidrmkushdeeflrscapudexuedeasssealtpeernpspulosw,opwetdtylagiismpti.aactiieoonahttoiirekissrnnnnhhdeers-,,.,
being hyperactive and inattentive, a problem that is officially called
attention-deficit/hyperactivity disorder, or ADHD (American Centipedes and Cough Medicine
One interesting aspect of trying to control
Psychiatric Association, 2000). Can beliefs unwanted symptoms with a drug treatment
Attention-deficit/hyperactivity disorder, or ADHD, is not diagnosed by
cure like real is that sometimes the drug is not really a
any medical tests but on the basis of the occurrence of certain behavioral drug because it has no proven medical
problems. A child must have six or more symptoms of inattention, such as medicine? effects. For example, in many parts of Asia,
making careless mistakes in schoolwork, not following instructions, and
being easily distracted, and six or more symptoms of hyperactivity, such as people believe powdered tablets made from centipedes are medi-
fidgeting, leaving classroom seat, and talking excessively. These symptoms cine for treating a variety of physical problems. Similarly, in the
should have been present from an early age, persisted for at least six United States, people spend billions of dollars a year on over-the-
counter cough medicines,
months, and contributed to maladaptive development.
One controversy surrounding ADHD involves diagnosis. Since including cough syrups
ADHD is based not on medical tests but rather on the occurrence of and cough drops, even
certain behavioral problems, how can parents and teachers distin- though there is no reli-
guish children with ADHD from those who are naturally outgoing able scientific evidence
and rambunctious (West et al., 2005)? Because of this difficulty, the t hat coug h med icat ions work
American Academy of Pediatrics issued guidelines for diagnosing (J. W. Payne, 2006). e use of centipedes
ADHD (AAP, 2000; M. Stein & Perrin, 2003). These guidelines and cough medicine, both questionable
stressed that, before the diagnosis of ADHD is made, a number medical treatments, raises the interesting Can centipedes cure all
of the symptoms described above should be present for at least six question of how much one’s mind or kinds of problems?
months. e guidelines focused on children aged 6 to 12 because one’s beliefs contribute to the development or treatment of physical
there isn’t sufficient evidence for making the diagnosis of ADHD at symptoms. We’ll discuss methods that researchers use to decide
earlier ages. e goal of these guidelines is to prevent merely ram- whether the effectiveness of a treatment is due to a drug’s medical
bunctious youngsters from being overmedicated while ensuring that effect or the person’s beliefs.
children with ADHD get the help they need (Leslie et al., 2004).
Another controversy is how to treat children with ADHD. To What’s Coming
help control Blake’s ADHD, he was given a popular drug that is a Our main focus in this module is to explore the methods that
relatively powerful stimulant, called Adderall. With the continued researchers use to answer questions, such as how to treat ADHD
aid of medication, Blake has become a successful student at the and why placebos work. Specifically, we’ll discuss the advantages
University of California at Berkeley and written his own memoir. and disadvantages of three major research methods—surveys, case
Researchers do not completely understand why stimulant drugs, studies, and experiments. We’ll explain which research procedures
such as Adderall or Ritalin, decrease activity in children. But drugs can identify cause-and-effect relationships and which cannot. We
to treat ADHD are undeniably popular as spending on these medi- begin with an overview of the three major research methods that
cations has reached $3 billion a year (M. Potter, 2006; Scrip, 2006). psychologists use to answer questions.
I N T R O D U C T I O N 27
A. Answering Questions
How do As you look at the photo of Blake neurological, cultural, and environmental factors (Barkley,
on the right, you see a mature 2006). Finally, the most popular treatment of ADHD is
researchers young adu lt. But, w it hout giving children a stimulant drug.
study ADHD? medication, Blake has great In the middle of these controversies are parents like
difficulty focusing: “A way you Blake’s mother, who, after dealing with a hyperactive
can think about it is if you’re taking a TV remote and and impulsive child from an early age, have little doubt
somebody else is just changing it uncontrollably and Image not ADHD exists and stimulant medication decreases
your mind is floating from the History Channel to avaliable hyperactivity and impulsivity. At the same time,
HBO to the Discovery Channel—it’s like you can’t critics warn that ADHD may be misdiagnosed or
really stay concentrated” (B. E. S. Taylor, 2008). overdiagnosed and that, while stimulant medi-
Twenty-five years ago, ADHD was a relatively cation may reduce activity, it fails to improve
small problem in the United States, while today mental functions such as ignoring distractions
it is the most commonly diagnosed behavioral and recalling information needed to reach a goal
problem in children. The diagnosis of ADHD is (Coghill, 2007).
not straightforward, since it is based on behavioral As researchers work to resolve the controversies
symptoms rather than medical tests. e proposed Researchers use three different surrounding ADHD, they are using three research
causes of ADHD are many, including genetic, research methods to study ADHD. methods—survey, case study, and experiment.
Survey Case Study Experiment
Suppose you wish to know how Suppose you wish to know in greater detail about how a Suppose you thought that sugar or
many children have ADHD, single child, such as Blake, developed ADHD, performs artificial dyes caused hyperactivity in
whether it occurs more in boys in school, makes friends, plays team sports, and deals your child and you wondered if this
or girls, which treatment is the with everyday problems. Or suppose you wish to know were true. For example, based on case
most popular, and how many about how a family copes with a child who has ADHD. studies and parents’ reports, one
children continue to have For example, one mother said, “Ritalin doesn’t take away researcher thought that certain artifi-
problems when they become the problems at all. It just helps him focus on what he’s cial dyes, chemicals, and sweeteners
adults. Researchers obtain this doing. You can talk to him; he can get his school work increased the activity and impulsive
information with surveys. done. It still takes him a long time to get things done. behavior of children diagnosed with
He’s still behind, emotionally and socially” (San Diego ADHD (Feingold, 1975). When
A survey is a way to obtain Tribune, November 27, 1989). When another mother was researchers want to identify a cause-
information by asking many indi- told that sugar doesn’t increase activity, she replied, “I say, and-effect relationship, such as
viduals—either person to person, they’re nuts! Where were they last Christmas when my whether sugar increases activity, they
by telephone, or by mail—to sons ate candy canes and green frosting for days and never use an experiment.
answer a fixed set of questions slept!” (Los Angeles Times, February 9, 1994). Researchers
about particular subjects. gather in-depth data about a particular individual with a An experiment is a method for identi-
case study. fying cause-and-effect relationships by
The disadvantage of a following a set of rules and guidelines that
survey is that such informa- A case study is an in-depth analysis of the thoughts, feel- minimize the possibility of error, bias, and
tion can contain errors or be ings, beliefs, experiences, behaviors, or problems of a single chance occurrences.
biased because people may not
remember accurately or answer individual. A disadvantage of an experiment
truthfully. e advantage of a One disadvantage of a case study is that its detailed is that information obtained in one
survey is that it is an efficient experimental situation or labora-
way to obtain much informa- information about a particular person, such as Blake, tory setting may not apply to other
tion from a large number of may not apply to other children with ADHD. situations. An experiment’s primary
people. advantage is that it has the greatest
One advantage of a case study is that its detailed potential for identifying cause-and-
But if researchers wanted to information allows greater understanding of a particular effect relationships with less error
know more about a particular person’s life. and bias than either surveys or case
person, they would use a case studies.
study. But if researchers wanted to establish whether sugar
really increases activity in children with ADHD, they
would use an experiment.
Which method Very o en, researchers use all three research methods—survey, case study, and experiment—because each provides
is best? a different kind of information. Surveys provide information about fixed questions from a large number of people.
Case studies give in-depth information about a single person. Experiments point to cause-and-effect relationships.
We’ll discuss the advantages and disadvantages of each of the three methods, beginning with surveys.
28 M O D U L E 2 P S Y C H O L O G Y & S C I E N C E
B. Surveys
Kind of Information
Almost every day the media report some new survey. Although surveys tell us what others believe or how they
What do behave, survey questions can be written to bias the answers; moreover, people may not always answer truthfully
surveys tell us? (N. Schwartz, 1999). For example, how many people do you think always wash their hands a er going to the
bathroom? We’ll sample some surveys and then discuss their problems.
Do you wash your hands? Do you multitask while driving? How many children are diagnosed with ADHD?
Although 92% of the people A survey of Recent telephone surveys of parents report
surveyed by telephone said they 1,503 drivers that 5% of U.S. children between 6 and 17
always washed their hands a er found that years old are diagnosed with ADHD. Boys
using a public bathroom, direct 72% say they are reported to be diagnosed with ADHD
observation of 6,076 people in do other twice as o en as girls. ADHD is reported
things while to be more common among adolescents
four major cities driving (use than younger children, and more com-
found that only 77% cell phone, mon among White and African American
really do and that drink, eat). children than Hispanic children (CDC, 2008c).
more women e percentages of people in each age ese examples show that surveys provide a great deal
(88%) washed group who multitask are 60% for of useful information. However, surveys have potential
their hands 16–17-year-olds, 78% for 18–30-year- problems with accuracy (as in the hand-washing survey)
than men olds, 80% for 31–44-year-olds, and and, as you’ll see next, with how questions are worded and
(66%) (ASM, 65% for 45–61-year-olds (NMI, 2008). who asks the questions.
2007).
Photo Credits: left, © Jutta Klee/Getty Images; center, © Blend Images/SuperStock; right, © Image Source/Getty Images Disadvantages Advantages
How questions are worded While guarding against error and bias,
You may be surprised to learn that surveys may get very different results depending on surveys can be a useful research tool to
how questions are worded. Here are two examples: quickly and efficiently collect information
on behaviors, beliefs, experiences, and atti-
QUESTION: “Would you say that QUESTION: “Would you say that tudes from a large sample of people and
industry contributes more or less to traffic contributes more or less to can compare answers from various ethnic,
air pollution than traffic?” air pollution than industry?” age, socioeconomic, and cultural groups.
Traffic contributes more: 24% Traffic contributes more: 45% For example, surveys suggest that ADHD
Industry contributes more: 57% Industry contributes more: 32% interferes with performance in school set-
tings, decreases the chances of graduating
ese two examples indicate that the way questions are phrased and the way the possible from high school, and may lead to conduct
answers are ordered can greatly influence people’s responses and, in this case, produce disorder problems in adolescence as well as
opposite results (reported in U.S. News & World Report, Dec. 4, 1995, p. 55). continued problems in adulthood (Root &
Resnick, 2003).
Who asks the questions
You may also be surprised to learn that the sex or race of the questioner can also affect Because surveys indicate that children
how people answer the questions. with ADHD have major problems in
school settings, psychologists are develop-
QUESTION: “ e problems faced by Blacks were brought on by Blacks ing methods for improving performance.
themselves.” These methods include: teaching ADHD
children how to organize their work, giving
When the interviewer was White, 62% of Whites who were interviewed agreed. them constant feedback on reaching their
When the interviewer was Black, 46% of Whites who were interviewed agreed. goals, and starting programs that train
teachers and families to work together to
ese two examples indicate that when asked about sensitive or emotional issues, help ADHD children control their disrup-
people take into account the race of the interviewer and tend to give socially acceptable tive behaviors (Hechtman et al., 2004).
rather than honest answers (U.S. News & World Report, Dec. 4, 1995, p. 55).
us, another advantage of surveys is their
We can conclude that surveys can be biased because people may not answer questions ability to identify problems and evaluate
truthfully, may give socially acceptable answers, or may feel pressured to answer in cer- treatment programs.
tain ways. Also, surveys can be biased by how questions are worded and by interviewing
a group of people who do not represent the general population (Gravetter & Forzano, However, if researchers wish to focus on
2009; S. J. Jackson, 2009). Despite these potential problems, surveys have advantages. a particular individual rather than a group,
they use a case study.
B . S U R V E Y S 29
C. Case Study
Kind of Information (left image). In it, he discusses the challenges he
Sometimes researchers answer faced from early childhood through the present. He
What’s a questions by studying a single talks about how he must take his ADHD medica-
tion, keep a daily routine, and make sure to get 9
case study? individua l in great detail, hours of sleep at night to keep his ADHD symptoms
which is called a case study. from getting out of control. As a result of his moti-
A case study is an in-depth analysis of the thoughts, vation and self-discipline, Blake enjoys a balanced
Image not college life spent studying, working out, playing
feelings, beliefs, or behaviors of a single person. avaliable music, socializing, volunteering, and, of course,
getting enough sleep (Anwar, 2008; B. E. S. Taylor,
We’ve been discussing the case of Blake Taylor 2007). Sometimes case studies help answer ques-
throughout the module. From the age of 3, Blake tions, but case studies can also result in wrong or
has had problems paying attention and complet- biased answers.
ing tasks. Throughout his childhood, he felt no
one understood the challenges he endured. To help
others understand what it’s like to live with ADHD,
he wrote his autobiography called ADHD & Me
Personal Case Study: Testimonial
Observations from case studies may be mis- recently, there are testimonials from parents that children with
Why did interpreted if the observer has preconceived attention-deficit disorder who ate foods with an artificial sweetener,
parents make notions of what to look for. For Average Ratings of Child Behaviors aspartame (Nutrasweet), showed noticeable
a mistake? example, beginning in the mid- and Cognitive Functions increases in symptoms.
1970s, parents were told that
food with artificial additives, dyes, and preservatives To test the accuracy of these recent
could cause hyperactivity in children (Feingold, testimonials, researchers asked teachers
Placebo 13.5 and parents to evaluate the behaviors and
1975). Shortly a er, parents reported that, yes indeed, Aspartame 13 cognitive functions of children who were
artificial additives caused a sudden increase in rest- given a capsule containing either ten times
lessness and irritability in their hyperactive children their normal daily intake of aspartame or a
(Feingold, 1975). The parents’ reports and beliefs that additives placebo. Neither parent, child, nor teacher knew if the capsule con-
cause hyperactivity are examples of another kind of case study, tained aspartame or the placebo. As the graph on the le shows,
called a testimonial. there was little or no difference between the effect of aspartame
A testimonial is a statement in support of a particular viewpoint based (Nutrasweet) and that of the placebo on the behaviors or cognitive
on detailed observations of a person’s own personal experience. functions of children with attention-deficit disorder (B. A. Shay-
However, contrary to the parents’ testimonials, researchers have witz et al., 1994). Although testimonials from parents, friends, or
generally found that amounts of artificial additives within a nor- peers can be very convincing, we’ll point out two problems that
mal range did not affect hyperactivity (Kinsbourne, 1994). More make testimonials especially susceptible to error.
Error and Bias One of the major problems with testimonials is that they are based on our personal observations, which
have great potential for error and bias. For example, if parents reported that sweeteners increased their son’s
What’s the problem activity, we would have to rule out personal beliefs and self-fulfilling prophecies.
with testimonials?
Personal beliefs. If parents hear that Self-fulfilling prophecy. If parents believe that artificial sweeteners cause problems,
artificial sweeteners may cause physi- they may behave in ways—being more strict or less sympathetic—that cause the problems
cal or psychological problems, they may to occur. is phenomenon is called a self-fulfilling prophecy.
interpret their child’s problems as caused A self-fulfilling prophecy involves having a strong belief or making a statement (prophecy) about
by artificial sweeteners. Because of biased a future behavior and then acting, usually unknowingly, to fulfill or carry out the behavior.
perceptions, parents may overlook If we strongly believe that something is going to happen, we may unknow-
other potential causes, such as frus- ingly behave in such a way as to make it happen (R. Rosenthal, 2003). Self-ful-
tration, anger, or changes in the filling prophecies reinforce testimonials and thus keep our biased beliefs alive.
child’s environment, and make the e main disadvantage of testimonials is their high potential for error and
error of focusing only on artificial bias. But they have the advantage of providing detailed information that may
sweeteners. If we believe strongly point to potential answers or lead to future studies. We’ll discuss how case
in something, it may bias our studies are used in developmental research in Module 18 and clinical research
perception and cause us to credit Parents mistakenly in Module 21.
believed that
artificial sweeteners
an unrelated treatment or event caused ADHD. Next, we’ll discuss how testimonials are a popular source of information,
as the reason for some change. especially when we are talking about placebos.
30 M O D U L E 2 P S Y C H O L O G Y & S C I E N C E
D. Cultural Diversity: Use of Placebos
Examples of Mind over Body
Psychologists are interested in how the mind gastric ref lux, high blood pressure, headaches) (Begley, 2008b;
Have you influences the body, such as happens when some- Christensen, 2001). Because placebos can be effective in treating
taken a one takes a pill that happens to be a placebo. different problems, almost 50% of U.S. doctors prescribe placebos
placebo? A placebo is some intervention, such as taking a to their patients (Steenhuysen, 2008a).
pill, receiving an injection, or undergoing an You may be wondering how it is that placebos can
operation, that resembles medical therapy but that, in fact, has no be so effective. Placebos may work because beliefs and
medical effects. thoughts are powerful enough to produce the same
A placebo effect is a change in the patient’s illness that is relief provided by real drugs (Ariely, 2008; Kluger,
attributable to an imagined treatment rather than to a medical 2009). For instance, researchers in one study injected
treatment. subjects with a pain-inducing solution and then falsely
For example, the results of a study involving children told subjects they had been injected with pain-reliev-
who were depressed showed that an antidepressant medi- ing medication (placebo). Pictures of subjects’ brains
cation decreased depression in 69% of children. However, were then taken (PET, p. 71), and results showed that
59% of the children reported equally good results from for those people who said they felt less pain, their
taking a placebo (a sugar pill) (Saxbe, 2004). In fact, many brain released natural painkillers a er the placebo
similar studies have reported a placebo to be just as effec- The power of placebos was injected (Haslinger, 2005). Our beliefs can actu-
tive as antidepressant medication (R. Rubin, 2008). is in the mind. ally change what is happening in our brain!
Researchers estimate that between 35% and 75% of patients ben- As you’ll see, testimonials from around the world claim that
efit from placebos for various problems (pain, depression, asthma, different kinds of placebos can cure a wide variety of symptoms.
Photo Credits: top, © Andy Ryan/Getty Images; bottom left, © DLILLC/Corbis; bottom center, © Photodisc/Getty Images Rhino Horn Centipedes Tiger Bones Cough Medication
Millions of people in China, Tai- In parts of Asia, a popular ere has been a massive When we have a cold
wan, ailand, and South Korea “medicine” to treat many kinds with a relentless cough,
claim rhino horn will increase of physical problems is a tablet decline of tigers in Asia many of us purchase
their sexual desire and stamina and made from the Korean centipede. because tiger bones are used cough syrup. In the
will cure everything from head- It is believed to cure arthritis, to treat ulcers, typhoid, United States, billions
aches and nosebleeds to fevers and kidney stones, malaria, skin malaria, joint pain, and of dollars are
typhoid. A single rhino horn diseases, and severe scars. Folk burns; to increase longevity; spent every
weighing 4 to 5 pounds will bring to improve sexual desire; year on
as much as $50,000 on the black logic seems to guide the use of and to cure devil possession cough
centipedes as “medicine.” For (Friend, 1997; T. Sylvester, medica-
market. Because of the high instance, centipedes have many 2009). In addition, wealthy tions
demand for rhino horns, legs and are used to treat leg Taiwanese pay $320 for a (cough
the number of problems (Pemberton, 2005; bowl of tiger penis soup that syrups
rhinos in Asia SACU, 2001). In fact, centipede is thought to increase flag- and loz-
has sharply poison may cause pain, nausea, ging libidos (Nagarahole, enges), yet
declined (Berger and fatal cases of organ failure 1994). Tiger bones and tiger there is no
& Cunningham, (Norris, 2008; Yuen et al., 2006). penises func- scientific evidence that
1994). Despite the tion as power- these over-the-counter
ful placebos medications work
healing claims of rhino horn, its in traditional (Ignelzi, 2006a; J. W.
basic ingredient is compacted hair Asian Payne, 2006).
(keratin), which has no proven medicine.
medicinal powers (Sierra, 1989).
Conclusion: Testimonials and Placebos
e main reason placebos are used worldwide, even to the point of destroying certain wild animals, is that the placebos’
Why are beneficial “medical” effects are supported by countless testimonials. For example, compared to the results of surveys,
placebos so testimonials are much more convincing because they are based on real-life experiences of friends, peers, and parents,
who are honest and believable. However, it is common for people, honest and trustworthy, to unknowingly make a
popular?
mistake and conclude a rhino horn, centipede, tiger bone, or cough medication is producing a beneficial “medical”
effect when the beneficial effect is actually being caused by the individual’s mental thoughts influencing the brain or body’s functioning
(Ariely, 2008).
As you’ll see next, people o en make mistakes about the effect of placebos because there is o en no way to figure out what causes what.
D . C U L T U R A L D I V E R S I T Y : U S E O F P L A C E B O S 31
E. Correlation
Definition What’s a The photo on the left shows a A correlation is an association or relationship in
boy running wild in a super- the occurrence of two or more events.
Research suggests that correlation? market. Researchers would like
ADHD has a genetic basis. to know if this boy’s hyperactiv- For example, if one twin has hyperactivity,
ity has a genetic basis. One way to identify genetic a correlation will tell us the likelihood that the
factors is to study identical twins because they share other twin also has hyperactivity. e likelihood
almost 100% of their genes. Suppose you were study- or strength of a relationship between two events
ing the occurrence of ADHD in identical male twins is called a correlation coefficient.
and found that about 75% of the time, if one identical
twin had ADHD so did the second twin (Faraone et A correlation coefficient is a number that indicates
al., 2005). is strong relationship between behaviors the strength of a relationship between two or more
in identical twins suggests a genetic basis for ADHD.
Such a relationship is called a correlation. events: the closer the number is to –1.00 or +1.00, the
greater is the strength of the relationship.
We’ll explain correlation coefficients in more
detail because they can be confusing.
Correlation Coefficients If each of 20 identical pairs showed equal levels of hyperactivity, the correlation coefficient would be Photo Credit: top, © Jose Azel/Aurora Quanta Productions
positive and perfect and would be indicated by a +1.00 correlation coefficient.
What are
these numbers? A perfect positive correlation coefficient of +1.00 means that an increase in one event is always
matched by an equal increase in a second event. For example, if one identical twin has hyperactivity,
ere are two major then the other twin always has hyperactivity. A correlation of +1.00 is virtually never found in applied
points to understand psychological research (Hemphill, 2003).
about correlations:
If some identical pairs but not all 20 pairs were similar in hyperactivity, the result would be a positive
First, a correlation correlation coefficient, which can range from +0.01 to +0.99.
means there is an
association between A positive correlation coefficient indicates that as one event tends to increase, the second event
two or more events. tends to, but does not always, increase.
For example, there is
an association, or cor- As the coefficient increases from +0.01 to +0.99, it indicates a strengthening of the relationship
relation, between the between the occurrence of two events.
sex of a child and the
occurrence of ADHD; If one twin of 20 pairs showed hyperactivity while the other twin sometimes did and sometimes did
four to five times more not show hyperactivity, the result would be no association, or zero correlation (0.00).
boys are diagnosed
with ADHD than girls. A zero correlation indicates that there is no relationship between the occurrence of one event and
the occurrence of a second event.
A second point
to understand about If, in some identical pairs, one twin showed an increase while the other showed an equivalent
correlations is that the decrease in activity, the result would be a negative correlation coefficient, which can range from
strength of the rela- −0.01 to −0.99.
tionship or association
is measured by a num- A negative correlation coefficient indicates that as one event tends to increase, the second
ber called a correlation event tends to, but does not always, decrease.
coefficient. Because the
correlation coefficient As the coefficient increases in absolute magnitude from −0.01 to −0.99, it indicates a strengthening
ranges from +1.00 to in the relationship of one event increasing and the other decreasing.
–1.00, its meaning can
be confusing. In the If one twin of 20 identical pairs showed hyperactivity and the second twin always showed decreased
boxes on the right, activity, the correlation coefficient would be negative and perfect and would be indicated by a −1.00
we’ll describe what correlation coefficient.
correlation coefficients
mean, beginning at A perfect negative correlation coefficient of −1.00 means that an increase in one event is always
the top of the scale matched by an equal decrease in a second event. For example, if one identical twin has hyperactivity,
with a +1.00. then the other twin always has decreased activity. A correlation of −1.00 is virtually never found in
applied psychological research (Hemphill, 2003).
32 M O D U L E 2 P S Y C H O L O G Y & S C I E N C E
Can you The media often headline interesting between two events, such as thinness and length of life,
findings: Thin people live longer than then it’s a correlation. In fact, all three findings reported
recognize a heavier ones; overweight people earn here are correlations. The reason you should check
correlation? less money than their peers; wearing whether some finding is a correlation is that correla-
school uniforms decreases violence. tions have one very important limitation: ey do not
Before you assume that one event causes the other, such as identify what causes what. For example, let’s look
thinness causing one to live longer, you must check to see what closely at findings about breast feeding and intelligence
researchers did. If researchers measured only the relationship test scores.
Correlation Versus Causation
The biggest mistake people make in discussing correlations is
assuming that they show cause and effect. For instance, many par- Breast Feeding and Adult Intelligence Test Scores
ents have been told that breast feeding their infant leads to greater 7–9 Months 106.0%
intelligence. e graph on the right shows that duration of breast
feeding was correlated with higher intelligence test scores during
adulthood. Since an increase in the duration of breast feeding was 4–6 Months 102.3%
associated with higher intelligence test scores, this is a positive 2–3 Months 101.7%
correlation (Mortensen et al., 2002).
Although the correlation between breast
feeding duration and intelligence test scores <1 Month 99.4%
is impressive, you must keep in mind that
even though breast feeding may have physical contact or special interactions between baby and mother
caused the higher test scores, correla- during breast feeding? Or, do infants who benefit most from their
tions themselves cannot demonstrate mother’s breast milk have specific genes that process the breast
cause and effect between variables. milk (Caspi et al., 2007; Kramer et al., 2008)? e correlation find-
ings leave many questions unanswered.
Although correlations cannot indicate cause-and-effect rela-
tionships, they do serve two very useful purposes: Correlations
help predict behavior and also point to where to look for possible
causes, as has happened in the case of lung cancer.
Photo Credits: top left, © Stockbyte/SuperStock; top right, © Digital Vision/Getty Images; bottom right, © Brand X/SuperStockLet’s think carefully what is actu-
In Thousandsally causing the higher intelligence test
scores. Is it something in the breast
Does breast feeding milk (a hormone or protein) that isn’t
increase intelligence? found in formula or cow’s milk? Is it the
Correlation as Clues Lung Cancer Deaths
160
Although cigarette smoking was positively correlated with lung cancer deaths (right graph), 120
it was unknown whether smoking was the cause of cancer. Acting on the clue that some
ingredient of cigarette smoke might trigger the development of lung cancer, researchers 80
rubbed tar, an ingredient of cigarette smoke, on the skin of animals. A er repeated applica- 40
tions over a period of time, the animals developed cancerous growths. is research proved
that tar could cause cancer. Later, researchers discovered that one particular ingredient of 1965 70 75 80 85 90 95
cigarette smoke (benzo[a]pyrene) turns off a gene that normally suppresses tumors. When
that particular gene is turned off by cigarette smoke, lung cancer develops (Liu et al., 2005). Source: American Cancer Society
In this case, correlations told researchers where to look for causes of lung cancer. In other
cases, correlations help predict behavior.
Correlation and Predictions Do IQ scores predict
academic success?
One way to predict how well students will do in academic settings is by looking at their IQ scores. For example,
there is a positive correlation, from +0.24 to +0.38, between IQ scores and performance in academic settings
(Chamorro-Premuzic & Furnham, 2008; D. M. Higgins et al., 2007). us, we would predict that individuals
who score high on IQ tests have the skills to do well in college. However, IQ scores are only relatively good
predictors for any single individual because doing well in college involves not only academic skills but also
other motivational, emotional, and personality factors that we’ll discuss in Module 13.
So far, we have discussed the advantages and disadvantages of two major research methods—surveys and
case studies—that psychologists use to answer questions. We have also explained a statistical procedure—
correlation—that shows the strength of relationships and points to possible causes of behaviors. Next,
we’ll describe the other kinds of research decisions that psychologists make as they try to understand and
explain behavior.
E . C O R R E L A T I O N 33
F. Decisions about Doing Research
Choosing Research Techniques
You are constantly asking questions about human behavior, such as “Why did she say that?” or “Why did he behave
What’s the that way?” Similarly, psychologists are continually asking questions, such as “What percentage of the population
best technique is gay?” or “Of what use are SAT scores?” or “How do we diagnose ADHD?” or “Can human stem cell transplants
for answering cure paralysis?” A er asking one of these questions, psychologists must decide which research technique or
procedure best answers it. We’ll describe four different techniques for finding answers.
a question?
Questionnaires and Interviews Laboratory Experiments
What percentage of the population is gay? This question is How do we diagnose ADHD? As of this writing, the diagnosis of
often answered by doing a survey using interviews or ques- ADHD is based primarily on behavioral symptoms, which are less
tionnaires. reliable than medical tests. For this reason, researchers are cur-
rently searching for more reliable tests to diagnose ADHD. To
An interview is a technique for obtaining information by asking ques- identify such tests, researchers are using laboratory experiments.
tions, ranging from open-ended to highly structured, about a subject’s A laboratory experiment is a technique to gather
behaviors and attitudes, usually in a one-on-one situation.
information about the brain, genes, or
A questionnaire is a technique for obtaining information by asking
subjects to read a list of written questions and check off specific behavior with the least error and bias
answers.
by using a controlled environment that
You might think this question about what percentage of the
population is gay would be relatively easy to answer. But three allows careful observation and
different surveys have reported three different answers: 2.3%,
10%, and 22% (Billy et al., 1993; Janus & Janus, 1993; Kinsey et measurement.
al., 1948). These different answers resulted from surveys using
differently worded questions, different groups of people, and For example, in the photo on the
different kinds of interview techniques. As we discussed earlier, right, a boy is taking a laboratory test
when it comes to surveys on personal issues—such as Did you that is believed to be an accurate way of Can a laboratory or
vote? Do you wear seat belts? Do you go to church? or What is diagnosing ADHD. In this test, children psychological test be used
your sexual preference?—people may give a desirable rather than wear special goggles to monitor their eye
a honest answer. to diagnose ADHD?
movements and are asked to follow spots of light moving across the
screen. Children with ADHD are expected to be able to follow the
light for only 3 to 5 seconds, whereas children without ADHD may
be able to follow the light for as long as 5 minutes (Vince, 2005).
Standardized Tests Animal Models Photo Credits: bottom left, © Jay Calderon, The Desert Sun; bottom right, © Masterfile/Royalty Free
Of what use are SAT scores? The standardized test that you Can mice help identify causes of schizophrenia? About 2.2 million
may be most familiar with is the SAT, which is given to many adults in the United States are living with schizophrenia (see p.
high school seniors to help predict how they will perform in col- 538), a severe mental illness. Scientists have been trying to find the
lege. Each year only 0.017% of students who take the SAT score a causes of schizophrenia for many years, and recently they have
perfect 2400, a feat accomplished by made some exciting advances with the use of animal models.
16-year-old high-school junior Austin An animal model involves examining or manipulating some behavioral,
Weiss (photo on le ) (Associated Press, genetic, or physiological factor that closely approximates some human
2005b; Lewin, 2006). problem, disease, or condition.
A standardized test is a technique to For example, researchers genetically
obtain information by administering altered mice to have extra receptors for
a psychological test that has been brain chemicals involved in schizophre-
standardized, which means that nia. As a direct result of these receptors,
Image not available due to the test has been given to hun- the mice had attention and memory Mice are used to study
copyright restrictions dreds of people and shown deficits similar to those of people with schizophrenia, a severe
to reliably measure thought schizophrenia. This finding could help
researchers develop new drugs to prevent mental illness.
patterns, personality traits,
emotions, or behaviors. such brain damage from occurring in people susceptible to schizo-
One disadvantage of phrenia (C. Brownlee, 2006a). One advantage of the animal model
standardized tests, such as the SAT, is that they may be biased is it answers questions about physiological factors that cannot be
toward a certain group of people. One advantage of standardized investigated in humans.
tests is that they allow comparisons to be made across schools, Deciding which of these four research techniques to use depends
states, and groups of people. Another well-known standardized on the kind of question being asked. As you’ll see next, the kind of
test is the IQ test, which we’ll discuss in Module 13. question also influences which research setting to use.
34 M O D U L E 2 P S Y C H O L O G Y & S C I E N C E
PowerStudy 4.5™
Choosing Research Settings Module 4
Which In trying to understand the kinds of problems faced by children with ADHD, psycholo- B. Studying the Living Brain
gists study these children in different research settings, which may include observing them in the home, in the
problems do classroom, on the playground, or at their individual work. In addition, researchers may try to find the causes of
children with ADHD by using different research settings, which may include studying children in the laboratory, hospital, or
ADHD have? clinic. All these research settings can be grouped under either laboratory or naturalistic environments. We’ll explain
each setting and compare their advantages and disadvantages, beginning with more naturalistic environments.
Naturalistic Setting Laboratory Setting
Parents and teachers want to know if ADHD children have different Is there something different about the brains of children
problems at home (photo below) than in school. Researchers answer this with ADHD? Questions about the brain are usually
question by studying ADHD children in different answered under very controlled conditions, such as in a
naturalistic settings (home versus school) (M. T. laboratory setting.
Stein, 2004). A laboratory setting involves studying individuals under sys-
A naturalistic setting is a relatively normal envi- tematic and controlled conditions, with many of the real-world
ronment in which researchers gather information by influences eliminated.
observing individuals’ behaviors without attempt- For example, researchers used special techniques (MRI
ing to change or control the situation. brain scans, p. 70) that actually took pictures of the living
For example, observations of children brains of children with and without ADHD. Researchers
with ADHD in school settings indicate that focused on specific areas of the brain involved in paying
they have difficulty remaining in their seats, attention and controlling impulses, which are difficult for
don’t pay attention to the teacher, can’t sit ADHD children. Findings showed that ADHD children
still, rudely interrupt the teacher or students, have smaller total brain size and smaller sizes of specific
Does this ADHD child and get angry when they don’t get their way brain areas involved in paying attention and controlling
have different problems (Junod et al., 2006). Parents report that, at impulses (prefrontal lobes, corpus callosum, cerebellum)
in school than at home? home, ADHD children do not respond when (D. E. Hill et al., 2003). Other research showed that these
called, throw tantrums when frustrated, and have periods of great activ- same brain areas of children
ity (Hancock, 1996). Based on these naturalistic observations, researchers with ADHD develop much Prefrontal lobe
and pediatricians developed a list of primary symptoms of ADHD (AAP, slower than in children
2000; M. Stein & Perrin, 2003). Similarly, psychologists study how normal without ADHD, which
people behave in different naturalistic settings, including schools, work- explains their smaller
places, college dormitories, bars, and sports arenas. One problem with brain size compared
naturalistic observations is that the psychologists’ own beliefs or values to same-age peers
may bias their observations and cause them to misinterpret behaviors. (Shaw et al., 2007).
One advantage of naturalistic observations is the opportunity to study Researchers use
behaviors in real-life situations and environments, which cannot or laboratory settings Corpus
would not be duplicated in the laboratory. to study and identify callosum
Case studies. As we discussed earlier, a single individual may be stud- a wide range of psycho- Cerebellum
ied in his or her natural environment, and this is called a case study. e logical and biological fac- Brain parts
case study approach is o en used in clinical psychology to understand tors involved in motivation, involved in ADHD
the development of a personality or psychological problem or in devel- emotion, learning, memory, drug
opmental psychology to examine a person’s behavior across his or her use, sleep, and mental disorders.
life span. One disadvantage of laboratory settings is that they
One disadvantage of a case study is that the information obtained is may be so controlled or artificial that their results are not
unique to an individual and may not apply to, or help us understand, the always transferable to, or meaningful for, real-life situa-
behaviors of others. One advantage of a case study is that psychologists tions. However, one advantage of the laboratory setting is
can obtain detailed descriptions and insights into aspects of an individu- psychologists can carefully control and manipulate one or
Photo Credit: © Ole Graf/zefa/Corbis al’s complex life and behaviors that cannot be obtained in other ways. more treatments while reducing error or bias from other
As you can see, naturalistic settings are very useful for observing how situational or environmental factors.
individuals behave in relatively normal environments. However, since Researchers may combine the advantages of natural-
naturalistic settings are uncontrolled and many things happen, research- istic and laboratory settings to identify cause-and-effect
ers find it difficult to identify what causes what. For this reason, research- relationships. at’s what happened when psychologists
ers may have to answer some questions in a more controlled setting, such answered the difficult question: Does Ritalin help children
as a laboratory or clinic. with ADHD?
F. D E C I S I O N S A B O U T D O I N G R E S E A R C H 35
G. Scientific Method: Experiment
Advantages of the Scientific Method cause-and-effect relationships. One way to reduce error and bias and
There have been many different treatments, identify cause-and-effect relationships is to do an experiment.
How do including diets, vitamins, drugs, and behavior
researchers therapy, that claimed to help children with An experiment is a method of identifying cause-and-effect relation-
ships by following a set of rules and guidelines that minimize the possibility
reduce error ADHD. To discover which of these claims
and bias? were valid, researchers followed a general of error, bias, and chance occurrences.
approach called the scientific method. An experiment, which is an example of using the scientific
The scientific method is an approach of gathering information and
method, is the most powerful method for finding what causes what.
answering questions so that errors and biases are minimized. If we wanted to find out if medication improves the behavior of
children with ADHD, we would want to do an experiment. We will
Remember that information from surveys, case studies, and tes- divide an experiment into seven rules that are intended to reduce
timonials has considerable potential for error and bias. Remember error and bias and identify the cause of an effect.
too that information from correlations can suggest, but not pinpoint,
Conducting an Experiment: Seven Rules
Some researchers and parents claimed that diets without sugar, artificial colors, and additives reduced ADHD
Why seven symptoms, but most of these claims proved false because the rules to reduce error had not been followed
rules? (Kinsbourne, 1994). Here are seven rules that reduce error and bias and that researchers follow when conducting
an experiment.
Rule 1: Ask Rule 2: Identify Rule 3: Choose
A er researchers identify the inde-
Every experiment begins with After researchers make their hypothesis, they identify a pendent and dependent variables,
one or more specific questions treatment that will be administered to the subjects. is they next choose the subjects for
that are changed into specific treatment is called the independent variable. the experiment. Researchers want
hypotheses. The independent variable is a treatment or something that to choose participants who are rep-
resentative of the entire group or
A hypothesis is an educated the researcher controls or manipulates. population, and they do this
guess about some phenomenon through a process called random
and is stated in precise, concrete The independent variable may be a single treatment, selection.
language to rule out confusion or such as a single drug dose, or various levels of the same
error in the meaning of its terms. treatment, such as different doses of the same drug. Random selection means that each
In our experiment, the independent participant in a sample population has
Researchers develop differ- variable is administering three different an equal chance of being selected for
ent hypotheses based on their doses of Ritalin and a placebo. the experiment.
own observations or previous A er researchers choose the treat-
research findings. Follow- ment, they next identify the behavior(s) Random Selection
ing this first rule, researchers of the subjects, called the dependent Examples of random selection
change the general question— variable, that will be used Independent include the way lottery numbers
Does Ritalin help children to measure the effects Variable: are drawn and selecting people
with ADHD?—into a very con- of the treatment. using a random number table.
crete hypothesis (see below). Drug treatment
e reason researchers randomly
Hypothesis: The dependent variable is one or select participants is to avoid any
Ritalin will increase potential error or bias that may
positive classroom more of the subjects’ behaviors that come from their knowingly or
behaviors of children unknowingly wanting to choose the
diagnosed with ADHD. are used to measure the potential “best” subjects for their experiment.
effects of the treatment or indepen-
dent variable.
The dependent variable, so
called because it is dependent
on the treatment, can include a
wide range of behaviors, such as
observable responses, self-reports
of cognitive processes, or record-
ings of physiological responses
from the body or brain. In the
present experiment, the depen-
Dependent Variable: dent variable is the teacher’s
Child’s positive rating of the child’s positive class-
room behaviors.
classroom behaviors
36 M O D U L E 2 P S Y C H O L O G Y & S C I E N C E
Rule 4: Assign Rule 6: Measure
A er randomly choosing the subjects, researchers then randomly By manipulating the treatment so that the experimental group
assign participants to different groups, either an experimental receives a different treatment than the control group, researchers are
group or a control group. able to measure how the independent variable (treatment) affects
The experimental group is composed of those those behaviors that have been selected as the dependent variables.
who receive the treatment. For example, the hypothesis in this study is: Ritalin will increase
The control group is composed of participants the positive classroom behaviors of children with ADHD. Research-
who undergo all the same procedures as the ers observe whether treatment (Ritalin or placebo) changes positive
Experimental experimental participants except that the control behaviors of ADHD children in the classroom. Positive behaviors
Group participants do not receive the treatment. include following a variety of classroom rules, such as remaining in
seat, not disturbing others,
In this study, some of Positive Behaviors in the Classroom
the children are assigned to the experimental not swearing or teasing, and
group and receive Ritalin; the other children following instructions. As the
are assigned to the control group and receive graph at the right indicates, Ritalin 87%
a similar-looking pill that is a placebo. Control ADHD children given pla- Placebo 69%
The reason participants are randomly Group cebos follow classroom rules
69% of the time, compared
assigned to either the experimental or con- with 87% for the children given Ritalin (Pelham et al., 2005). us,
trol group is to take into account or control for other factors or
traits, such as intelligence, social class, age, sex, and genetic dif- compared to placebos, Ritalin increases positive behaviors in the
ferences. Randomly assigning participants reduces the chances classroom. However, to be absolutely sure, researchers must analyze
that these factors will bias the results. the results more carefully by using statistical procedures.
Rule 5: Manipulate Rule 7: Analyze
A er assigning participants to experimental and control groups, Although there appears to be a large increase in positive behaviors,
researchers manipulate the independent variable by administer- from 69% for the placebo control group to 87% for the Ritalin exper-
ing the treatment (or one level of the treatment) to the experi- imental group, researchers must analyze the size of these differences
mental group. Researchers give the same conditions to the with statistical procedures.
control group but give them a different level of the treatment, no Statistical procedures are used to
treatment, or a placebo. determine whether differences observed
In this study, researchers give the experimental group a pill in dependent variables (behaviors) are due
containing Ritalin, while the control group receives a placebo. to independent variables (treatment) or to
Drugs and placebos are given in a double-blind procedure. error or chance occurrence.
A double-blind procedure Using statistical procedures,
means neither participants which are described in Appendix A,
nor researchers know which researchers compared the effect of
group is receiving which the placebo with that of Ritalin on
treatment. positive behaviors. ey concluded
A double-blind pro- that, compared with the placebo, Statistical analysis shows if the
cedure is essential in Ritalin significantly increased pos-
result occurred by chance.
drug research to con- itive behaviors. In this case, signifi-
trol for self-fulfilling cantly means there was a 95% likelihood that it was Ritalin and not
prophecies (see p. 30), some error or chance occurrence that increased positive behaviors
placebo effects (see p. 31), (Pelham et al., 2005).
and possible influences or Double-blind procedure is an These significant findings support the hypothesis that Ritalin
biases of the experimenters. important research tool. increases positive classroom behaviors of children with ADHD.
Conclusion
What does By following these seven rules for conduct- surveys, testimonials, correlations, or case studies. Even so,
ing an experiment, researchers reduced the researchers usually repeat experiments many times before being
an experiment chances that error or bias would distort the confident that the answers they found were correct. at’s why a
tell you? major finding, which was that Ritalin newly reported finding, no matter how significant, is usually
regarded as questionable until other researchers have been able to
increased the positive behaviors of children repeat the experiment and replicate the finding.
in the classroom. is example shows that when an experiment is
run according to these seven rules, it is a much more powerful A er the Concept Review, we’ll discuss why, a er more than 20
method for identifying cause-and-effect relationships than are years of research, there are still controversies surrounding ADHD.
G . S C I E N T I F I C M E T H O D : E X P E R I M E N T 37
Concept Review
1. If psychologists obtain information through (a) setting. A varia- Prefrontal lobe
an in-depth analysis of the thoughts, beliefs, or
behaviors of a single person, this method is called tion of this approach is to study a single
a (a) . If a method is used that individual in great depth in his or her
Image not minimizes error and identifies cause-and-effect own environment, which is called a
avaliable (b) . If psychologists
study individuals under carefully Corpus
relationships, it is called an (b) . callosum
If individuals are asked a fixed set of questions,
it is called a (c) . If individuals controlled conditions, they are using Cerebellum
a (c) setting.
make statements in support of a particular viewpoint on the basis
of personal experience, it is called a (d) . 6. One example of searching for cause-and-effect relationships by
following the rules and guidelines of the scientific method is to
2. Some intervention that is designed to look answer questions by conducting an , which has
like a medical treatment but that has no actual
medical effect is called a (a) . seven rules.
A change in a patient’s illness that is due to a 7. If you are conducting an experiment, you should follow 7 rules.
supposed treatment and not to any medical Rule 1 is to ask specific questions in very concrete terms: these
therapy is called a (b) .
statements are called (a) .
3. Psychologists describe the association, relation- Rule 2 is to identify the treatment, which is called
+1.00 ship, or linkage among two or more events as a
(a) . They describe the strength the (b) , and to choose the behav-
iors or responses that will be observed to judge the
of such a relationship by a number called the effectiveness of the treatment. These behaviors or
+ 0.50 (b) , which may vary from −1.00 to responses are called the (c) .
+1.00. If an increase in one event is associated with an Rule 3 is to choose subjects through a
0.00 increase in a second event, this relationship is called a
(c) correlation. If an increase in one process called (d) ,
which gives everyone in a sample popu-
event is associated with a decrease in a second event, lation an equal chance of being selected.
–0.50 this relationship is called a (d)
correlation. Finding that two or more events are
linked together does not prove that one event Rule 4 is to assign subjects to different
groups by random selection. The group
–1.00 (e) the other. that will receive the treatment is called
4. Psychologists use at least five common research techniques. the (e) , and the group
that undergoes everything but the treatment is called the
They can ask subjects oral or written questions by using (f) .
(a) and (b) . They might ask
subjects to answer questions on established tests, which are called Rule 5 is to manipulate the (g)
(c) tests. They might by administering it to the experimental group but
observe and measure behaviors, not the control group.
brains, or genes with the least
error and bias by using a con- Rule 6 is to measure the
trolled environment, called a effects of the independent variable on
(d) . They behaviors that have been selected as the
could study some question or (h) .
problem in animals by developing Rule 7 is to analyze the difference between
an (e) that closely the experimental and control groups by
approximates the human condition. using (i) .
5. If psychologists study individuals in their real-life environ- 8. Researchers usually repeat experiments many times to make
ments, without trying to control the situation, they are using a sure that their are correct.
Answers: 1. (a) case study, (b) experiment, (c) survey, (d) testimonial; 2. (a) placebo, (b) placebo effect; 3. (a) correlation, (b) correlation
coefficient, (c) positive, (d) negative, (e) causes; 4. (a) questionnaires, (b) interviews, (c) standardized, (d) laboratory experiment, (e) animal model;
5. (a) naturalistic, (b) case study, (c) laboratory; 6. experiment; 7. (a) hypotheses, (b) independent variable, (c) dependent variable, (d) random
selection, (e) experimental group, (f) control group, (g) independent variable, (h) dependent variables, (i) statistical procedures; 8. answers or results
38 M O D U L E 2 P S Y C H O L O G Y & S C I E N C E
H. Research Focus: ADHD Controversies
Why do You might ask why, a er so many years of research, there are still controversies over how to diagnose and treat ADHD.
controversies Although researchers have reached the first goal of psychology, which is to describe ADHD, they have not reached the
still remain? second goal, which is to explain the causes of ADHD, which will lead to better treatment. Explaining the causes of
ADHD means combining biological, psychological, behavioral, and cultural factors, which is a slow process. We’ll
review the current controversies involving ADHD to show how far researchers have come and how far they have to go.
Controversy: Diagnosis
e first controversy involves the accuracy and reliability of child is overwhelmed by the demands of school and acts
how ADHD is diagnosed. In the United States, as many as 7 outgoing, rambunctious, or difficult to discipline (Sinha,
million school-age children are diagnosed with ADHD, 2001). Sometimes children with problems in learning,
with three times as many boys having ADHD as girls vision, or hearing are misdiagnosed with ADHD (Hillier,
(B. Bower, 2006b). 2004; Lyle, 2003).
e controversy arises from the fact that the current Because of diagnostic difficulties, pediatricians
diagnosis of ADHD is based solely on reported and and family doctors were recently given the following
observed behavioral symptoms rather than on medical guidelines for diagnosing ADHD: Children should be
or laboratory tests. Because the behavioral symptoms 6–12 years old, show six or more symptoms of inat-
vary in severity (more or less), setting (home versus tention and hyperactivity, have symptoms for at least
school), and culture (fewer Asian American children six months, and exhibit symptoms in both home and
than African American), there is the potential for mis- school (J. E. Allen, 2000). e purpose of the guidelines
There are three
big controversies
diagnosis (Root & Resnick, 2003). For example, parents surrounding ADHD. is to prevent the merely rambunctious child from being
or teachers may label a child as having ADHD if the diagnosed with ADHD and given unnecessary drugs.
Controversy: Treatment
e second controversy involves how best to treat ADHD. As we dis- Combined Drug and Behavioral Treatment
cussed earlier (p. 30), researchers found that using diets that avoid A combination of Ritalin (methylphenidate) and behavioral treat-
artificial flavors and colors, preservatives, artificial sweeteners, and ment is recommended when children have severe ADHD, such as
sugars did little to reduce hyperactive behaviors (Kinsbourne, 1994). when ADHD symptoms cause a major disruption in home and/or
More recently, researchers have compared nondrug and drug treat- school (Barkley, 2006). The use of Ritalin has risen 600% since
ments for ADHD and made the following recommendations. 1993, and total ADHD medication sales more than quadrupled
between 2000 and 2004 (Alonso-Zaldivar, 2006; Haislip, 2003).
Nondrug, Behavioral Treatment Currently, there are more than 2.5 million Americans aged 19
ere is a nondrug, behavioral treatment pro- or younger who are using ADHD medications (Boyles, 2008).
ADHD medications help decrease children’s hyperactivity
gram that involves changing or modifying and increase their concentration; however, they may cause side
undesirable behaviors by using learning prin- effects, including sleeping and eating problems, irritability,
ciples (p. 232). Such a behavioral treatment and slowed growth rate (B. Bower, 2006c). ADHD medications
Photo Credits: top, © Ole Graf/zefa/Corbis; bottom, © Peter Titmuss/Alamy program, which requires considerable efforts don’t improve some of the skill deficits of these children, such
by the parents and teachers, has been effective as difficult interactions with peers and parents (Fabiano, 2008).
in reducing ADHD symptoms (Barkley, 2006; Because of the risk for serious side effects and the increase in
DuPaul, 2008). Ritalin use, the Food and Drug Administration recommended
Ritalin and other similar drugs include a warning (New York
Experts in the treatment of ADHD recom- Times, Feb. 12, 2006). e use of drug and/or behavioral treat-
mend a behavioral treatment program be used ment for ADHD depends on an accurate diagnosis, the sever-
for preschool-age children with ADHD, for Use of Ritalin: 600% ity of symptoms, and concerns of teachers and parents.
milder forms of ADHD, for children who also increase since 1993
have deficits in social skills, and when the fam-
ily prefers the nondrug, behavioral treatment.
Controversy: Long-Term Effects medication and/or behavioral programs that focus on setting goals,
establishing rules, and rewarding performance should be encour-
e third controversy involves the long-term effects of ADHD. It aged to help those with ADHD deal with adolescence and adult-
used to be thought that children outgrew ADHD, but researchers hood (Barkley, 2006; Barkley et al., 2008).
have found that even when ADHD children are treated with Ritalin,
50% continue to have problems as adults. In fact, 1.5 million adults e controversies surrounding ADHD point out the difficulties in
in the United States take ADHD medication (Alonso-Zaldivar, understanding, explaining, and treating complex human problems,
2006). Adults with ADHD are more likely to have school, work, and such as ADHD. Using Ritalin to treat children also raises questions
relationship problems (Barkley et al., 2008; Medical News Today, about the rights of subjects, both humans and animals, in research.
2005). Because ADHD is a continuing problem, the use of
H . R E S E A R C H F O C U S : A D H D C O N T R O V E R S I E S 39
I. Application: Research Concerns
Concerns about Being a Subject
What’s it When you hear about a new research finding—such as a drug to control
weight or treat depression, or the discovery of a gene related to happiness, or
like to be ways to improve memory—you rarely think about the treatment of subjects,
a subject? humans and animals, used in these experiments.
For example, if you were asked to volunteer to be a participant, you
would certainly be concerned about whether someone has checked to ensure that the experiment
is safe, that there are safeguards to protect you from potential psychological or physical harm, and
that you won’t be unfairly deceived or made to feel foolish. ese are all real concerns, and we’ll
discuss each one in turn.
Additionally, a separate and controversial question concerns the use of animals in research.
We’ll answer this question in some detail, since there are many misconceptions about the use and
misuse of animals in research.
We’ll begin by considering the concerns of human subjects.
Code of Ethics participants (human or animal) by carefully checking the proposed
experiments for any harmful procedures (Breckler, 2006).
If you are a college student, there is a good possibility that you will Experiments are not approved unless any
be asked to participate in a psychology experiment. If you are con- Are my potentially damaging effects can be eliminated or
sidering becoming a subject, you may wonder what rights counteracted. Counteracting potentially harmful
kinds of safeguards are used to protect subjects’ rights protected? effects is usually done by thoroughly describing
and privacy.
the experiment, a process called debriefing.
The American Psychological Association Debriefing includes explaining the purpose and method of the
has published a code of ethics and conduct for
psychologists to follow when doing research, experiment, asking the participants their feelings about being par-
counseling, teaching, and related activities
(American Psychological Association, 2002). ticipants in the experiment, and helping the participants deal with
This code of ethics spells out the respon-
sibilities of psychologists and the rights of possible doubts or guilt that arise from their behaviors in the
participants.
experiment.
Besides having to follow a code of ethics, psychologists must
submit the details of their research programs, especially those During the debriefing sessions, researchers will answer
with the potential for causing psychological or physical harm, to any questions or discuss any problems that participants may have.
university and/or federal research committees (institutional review e purpose of debriefing is to make sure that participants have
boards). The job of these research committees is to protect the been treated fairly and have no lingering psychological or physical
concerns or worries that come from participating in an experiment
(Aronson et al., 2004). Photo Credits: center, © Craig McClain; bottom, © Jack Hollingsworth/Getty Images
Role of Deception
When recruiting participants for their experiments, psychologists Association’s (2002) code of ethics. For example, researchers must
usually give the experiments titles, such as “Study of eyewitness justify the deceptive techniques by the scientific, educational, or
testimony” or “Effects of alcohol on memory.” e reason for using applied value of the study and can use deception only if no other
such general titles is that researchers do not want to create specific reasonable way to test the hypothesis is available (APA, 2002).
expectations that may bias how potential partici-
pants will behave. It is well known that an experi- Another way to avoid bias from par-
Will they ticipants’ expectations is to keep both the
try to trick or researcher and participants in the dark about
ment’s results may be biased by a number of deceive me? the experiment’s true purpose by using a
factors: by participants’ expectations of how they double-blind procedure. As discussed earlier
should behave, by their unknowingly behaving (p. 37), a double-blind procedure means that
according to self-fulfilling prophecies, or by their efforts to neither participants nor researchers are aware
make themselves look good or to please the experimenter. of the experiment’s treatment or purpose.
One way that researchers control for participants’ expecta-
tions is to use bogus procedures or instructions that prevent Thus, researchers must be careful not to
participants from learning the experiment’s true purpose. reveal too many details about their experi-
However, before researchers can use bogus or deceptive ments lest they bias how potential subjects
methodology, they must satisfy the American Psychological may behave.
40 M O D U L E 2 P S Y C H O L O G Y & S C I E N C E
Photo Credits: top and bottom, Courtesy of the Foundation for Biomedical Research Ethics of Animal Research The small print in the poster reads, “Without animal answer is always yes because I know that
research, we couldn’t have put an end to polio, there is no other way for medicine to prog-
How many animals are used ress but through animal experimentation
in research? smallpox, rubella and diphtheria. Now, some would and that basic research ultimately leads to
like to put an end to animal research. Obviously, unforeseen benefits” (Morrison, 1993).
It is estimated that over 25 million animals they don’t have cancer, heart disease or AIDS.”
are used each year in biomedical research, The small print in the poster reads, “Recently, a According to Frederick King, the former
which includes the fields of psychology, chair of the American Psychological Asso-
biology, medicine, and pharmaceuticals surgical technique perfected on animals was used to ciation’s Committee on Animal Research
(Humane Society, 2008). Although these remove a malignant tumor from a little girl’s brain. We and Experimentation, animal research
numbers seem large, they are small in com- has resulted in major medical advances,
parison to the 5 billion chickens eaten lost some lab animals. But look what we saved.” new treatments for human diseases, and a
annually by people in the United States. better understanding of human disorders
However, it is the use of animals in research (F. A. King et al., 1988).
that has generated the most concern and
debate (Rowan, 1997). In the field of psychology, animal
research has led to a better understand-
In the field of psychology, about 7 to ing of how stress affects one’s psycho-
8% of research involves the use of animals. logical and physical health, mechanisms
About 90% of the nonhuman animals underlying learning, the development
used by researchers are rats, mice, and and treatment of depression, anxiety, and
birds, while the remaining 10% are other schizophrenia, and critical information
animals such as cats, dogs, and monkeys about sensory processes of taste, vision,
(C.A.R.E., 2008). We’ll examine the justi- hearing, and pain perception, to mention
fication for using animals in research and but a few (C.A.R.E., 2008).
how their rights are protected.
Who checks on the use of
Are research animals animals in research?
mistreated?
Numerous government and university
You may have seen a disturbing photo or regulations ensure the proper care and
heard about a laboratory animal being humane treatment of laboratory animals.
mistreated (C.A.R.E., 2008). The fact is For example, the U.S. Department of Agri-
that, of the millions of animals used in culture conducts inspections of all animal
research, only a few cases of animal mis- research facilities to ensure proper housing
treatment have been confirmed. That is and to oversee experimental procedures
because scientists know that proper care that might cause pain or distress. Also,
and treatment of their laboratory animals universities have committees with author-
are vital to the success of their research. ity to decide whether sufficient justification
To abolish the use of all laboratory ani- exists for using animals in specific research
mals because of one or two isolated cases projects (Kalat, 2004).
of mistreatment would be like abolishing
all medical practice because of isolated How do we strike a balance?
cases of malpractice. Instead, researchers One of the basic issues in animal research
support the Animal Research Act, which is how to strike a balance between animal
balances the rights of animals to be treated rights and research needs (Albright et al.,
with care with the needs for advancing the 2005). Based on past, present, and poten-
medical, physiological, and psychological tial future benefits of animal research,
health of humans (Albright et al., 2005). many experts in the scientific, medical,
and mental health communities believe
Is the use of animals justified? the responsible use of animals in research
Adrian Morrison, director of the National is justified. is is especially true in light
Institute of Mental Health’s Program for of recent rules that regulate the safe and
Animal Research Issues, offers this view: humane treatment of animals kept in labo-
“Because I do experimental surgery, I go ratories or used in research (C.A.R.E.,
through a soul-searching every couple of 2008; OACU, 2008).
months, asking myself whether I really
want to continue working on cats. The
I . A P P L I C A T I O N : R E S E A R C H C O N C E R N S 41
Summary Test
A. Answering Questions E. Correlation
1. Psychologists use at least three methods 5. If two or more events are associated or linked .
to answer questions or obtain information. together, they are said to be (a)
An in-depth analysis of a single person’s The strength of this association is indicated by a +1.00
thoughts and behaviors is called a number called the (b) , which has + 0.50
(a) . One advantage of Image not a range from −1.00 to +1.00.
this method is that researchers obtain avaliable 0.00
–0.50
detailed information about a person, but 6. If there were a perfect association between two –1.00
events—for example, when one increased, the other
one disadvantage is that such information did also—this would be called a (a) .
may not apply to others. Asking a large
number of individuals a fixed set of questions is called a If an increase in one event is usually, but not always,
accompanied by an increase in a second event, this is
(b) . Gathering information in a controlled called a (b) . If an increase in one
laboratory setting is called an (c) .
event were always accompanied by a decrease in a sec-
ond event, this would be called a (c) .
B. Surveys If an increase in one event is usually, but not always,
2. Measuring the attitudes, beliefs, and accompanied by a decrease in a second event, this is
behaviors of a large sample of individuals called a (d) .
by asking a set of questions is called a
7. Although a correlation indicates that two or more events are
. One advantage of this occurring in some pattern, a correlation does not identify which
method is that psychologists can quickly and event may (a) the other(s). Although correlations
efficiently collect information about a large do not identify cause-and-effect relationships, they do provide
number of people. One disadvantage is that (b) as to where to look for causes and they help
people may answer in a way that they think to (c) behavior.
is more socially acceptable.
C. Case Study F. Decisions about Doing Research
3. A statement that supports a particular view- 8. Psychologists may answer some question by
using one or more of five com-
point and is based on a person’s own experience monly used research techniques.
is called a (a) , which has two
potential sources of error and bias. First, Asking questions about people’s
attitudes and behaviors, usually in
strongly held personal beliefs may bias an a one-on-one situation, is using an
individual’s (b) of events.
Second, believing strongly that something (a) . Asking sub- Photo Credits: center left, © Blend Images/SuperStock; bottom left, © DLILLC/Corbis
jects to read a list of questions and indicate
will happen and then unknowingly acting a specific answer is using a (b) . Asking
in such a way as to make that something occur can cause an error
called (c) . This source of error is one of the subjects to complete established tests that measure personality,
intelligence, or other behaviors is using (c) . If
major reasons that people believe that their (d) psychologists study subjects’ behaviors under carefully controlled
are true.
conditions that allow manipulation of the treatment, they are con-
ducting a (d) . Psychologists can study a problem
D. Cultural Diversity: Use of Placebos using animals by developing an (e) , which
closely approximates the human disease or condition.
4. Some intervention that resembles a medical therapy but
that, in fact, has no medical effects is called a 9. Psychologists conduct research in two common settings. If
(a) . If a person reports psychologists obtain information by observing an individual’s
an improvement in some medical condition behaviors in his or her environment, without attempts to control or
that is due to a supposed treatment rather manipulate the situation, they would be using a .
than some medical therapy, that is called a The advantage of this method is that it gives information that
(b) . One reason people would be difficult to obtain or duplicate in a laboratory. The dis-
around the world believe in placebos is that advantage of this method is that the psychologists’ own beliefs or
people give (c) to their values may bias their observations and cause them to misinterpret
effectiveness. the behaviors under observation.
42 M O D U L E 2 P S Y C H O L O G Y & S C I E N C E
10. If psychologists study a single individual in considerable Rule 7 is to analyze differences between behaviors of subjects
depth in his or her own environment, they are using a in the experimental group and those in the control group by
using various (j) , which determine whether
. The advantage of this method is that it results differences were due to the treatment or to chance occurrences.
in detailed descriptions and insights into many aspects of an By following these seven rules, researchers reduce the chances
individual’s life. The disadvantage is that the information that (k) caused their results.
obtained may be unique and not applicable to others.
Prefrontal lobe 11. If psychologists want to study individu- H. Research Focus: ADHD Controversies
als under controlled and systematic condi-
tions, with many of the real-life factors
removed, they do the study in a 13. One controversy over ADHD is that, as
of this writing, the diagnosis of ADHD is
. The advantage of this based on (a) observations,
Corpus setting is that it permits greater control which are not always clear-cut, rather than
callosum and manipulation of many conditions on more reliable (b) tests.
Cerebellum while ruling out possible contaminating Another controversy involves how best to
factors. The disadvantage of this setting is that it may be too treat ADHD. For more severe ADHD,
artificial or controlled, so that the results may not necessarily
apply to real-life situations. researchers recommend a combination of
(c) and (d) treatment. How-
ever, even though Ritalin can decrease hyperactivity in children
G. Scientific Method: Experiment and increase their ability to pay (e) , Ritalin
does not necessarily improve reading or social skills and does not
12. The scientific method offers a set of rules necessarily reduce problems occurring during adolescence and
or guidelines on how to conduct research adulthood.
with a minimum of error or bias. We have
divided these guidelines into seven rules. I. Application: Research Concerns
Rule 1 is to make a statement in precise, 14. One method of counteracting potential
concrete terms. Such a statement is called a harmful effects on experimental subjects
(a) , which researchers often develop based on is by thoroughly them.
previous observations or studies. This includes explaining the purpose and
Rule 2 is to identify the treatment or something the experimenter method of the experiment, asking subjects
manipulates, which is called the (b) . In addition,
the experimenter selects behaviors that are to be used to measure about their feelings, and helping subjects
deal with possible doubts or problems
the potential effects of the treatment. These selected behaviors are arising from the experiment.
called the (c) , and they may include a wide
range of behaviors, such as cognitive processes, observable 15. The justification for using in research is
that it has resulted in major medical advances, treatments for
behaviors, or measurable physiological responses. diseases, and understanding of human disorders.
Rule 3 is to choose subjects so that each one in a sample has an
equal chance of being selected. One procedure for doing so is
Photo Credits: (#13) © Peter Titmuss/Alamy; (#14) © Craig McClain called (d) . Answers: 1. (a) case study, (b) survey, (c) experiment; 2. survey;
3. (a) testimonial, (b) perceptions, (c) self-fulfilling prophecy,
Rule 4 is to assign subjects randomly to one of two groups. (d) testimonials; 4. (a) placebo, (b) placebo effect, (c) testimonials;
The group that will receive the treatment is called the 5. (a) correlated, (b) correlation coefficient; 6. (a) perfect positive
(e) , and the group that will undergo everything correlation, (b) positive correlation, (c) perfect negative correlation,
but the treatment is called the (f) . (d) negative correlation; 7. (a) cause, (b) clues, (c) predict; 8. (a) interview,
(b) questionnaire, (c) standardized tests, (d) laboratory study or experi-
Rule 5 is to manipulate the (g) by administering ment, (e) animal model; 9. naturalistic setting; 10. case study;
it (or one level of it) to the experimental group but not to the con- 11. laboratory setting; 12. (a) hypothesis, (b) independent variable,
trol group. The procedure for preventing researchers or subjects (c) dependent variables, (d) random selection, (e) experimental group,
from knowing who is getting the treatment is called the (f) control group, (g) independent variable, (h) double-blind procedure,
(h) . (i) dependent variables, (j) statistical procedures, (k) error or bias;
13. (a) behavioral, (b) medical or laboratory, (c) Ritalin, (d) behavioral,
Rule 6 is to measure the effects of the independent variable on (e) attention; 14. debriefing; 15. animals
behaviors that have been selected as the (i) .
S U M M A R Y T E S T 43
Critical Thinking
Does Binge Drinking Cause
Later Health Problems?
QUESTIONS It is well known that adolescent Also, late onsetters were more likely 3 Why were Photo Credit: © Image Source/Getty Images
drinking causes plenty of im- to get sick than nonbinge drinkers, “escalators”
1What are the three mediate health problems such as but surprisingly escalators were not found not to have
major methods for sleeplessness, fatigue, headaches, found to have poorer health than poorer health than
answering questions and lower cognitive functioning. teens who did not binge drink. “nonbinge drinkers”?
in psychology, and But does adolescent binge drink-
which method was ing (having at least 5 alcoholic The researchers adjusted the 4 What should
used in this study? drinks on one occasion) have any study’s statistical analyses to ac- alcohol prevention
long-term effects on health? Ac- count for factors that might explain programs emphasize
2 Do the results of cording to a recent study, the an- the findings, such as income level, to help reduce teen-
this study show swer is yes. Binge drinking during gender, ethnicity, and level of drink- age binge drinking?
a cause-and-effect adolescence was found to have a ing at age 24. Even so, they still
relationship between variety of long-term, negative found teenage binge drinking to be 5 What are the
teenage binge drink- health consequences, and the associated with later health prob- advantage and
ing and poorer health risks remained even for people lems. These results support the role disadvantage of this
for young adults? Why who stopped drinking during of alcohol in long-term health risk. study?
or why not? their teenage years.
Although these findings are im- 6 What bias or
Researchers at the University of pressive, the researchers cannot con- error may explain
Washington followed 808 people clude that adolescent binge drinking why an adult blames
(about equal numbers of males and causes later health problems. In- his recent headaches
females) from ages 10 to 24, inter- stead, they state that those who and sleeping prob-
viewing them numerous times ask- binge drink may choose certain life- lems on the binge
ing about their drinking and other styles and engage in certain behav- drinking he did during
drug use, exercise habits, and health. iors that more directly contribute to adolescence?
They identified four types of teen- poorer health. When these factors
age drinkers: nonbinge drinkers (in- are better understood, interventions ANSWERS
cluding nondrinkers), who never or can be more effective in reducing TO CRITICAL
rarely engaged in binge drinking; the occurrence of teenage binge THINKING
chronic heavy drinkers, who drank drinking. (Adapted from Oesterle et QUESTIONS
throughout adolescence; escalators, al., 2004; Querna, 2004)
who started drinking in mid-adoles-
cence and quickly increased their al-
cohol use; and late onsetters, who
began drinking late in their teenage
years.
Findings showed that nonbinge
drinkers were in the best health at
age 24, based on weight, physical ac-
tivity, blood pressure, and number
of times they got sick. Chronic heavy
drinkers were in the worst physical
health. For example, compared to
nonbinge drinkers, they were almost
4 times as likely to be overweight
and to have high blood pressure.
44 M O D U L E 2 P S Y C H O L O G Y & S C I E N C E
Links to Learning
Key Terms/Key People Learning Activities
ADHD diagnosis, 39 experimental group, 37 PowerStudy for Introduction PowerStudy 4.5™
ADHD long-term hypothesis, 36 to Psychology 4.5
independent variable, 36
effects, 39 interview, 34 Try out PowerStudy’s SuperModule for Psychology and Science! In addition to
ADHD treatment, 39 laboratory experiment, 34 the quizzes, learning activities, interactive Summary Test, key terms, module
animal model, 34 laboratory setting, 35 outline and abstract, and extended list of correlated websites provided for all
Animal Research Act, 41 naturalistic setting, 35 modules, the DVD’s SuperModule for Psychology and Science features:
animal research, ethics, 41 negative correlation t 4FMG QBDFE
GVMMZ OBSSBUFE MFBSOJOH XJUI B NVMUJUVEF PG BOJNBUJPOT
attention-deficit/ t 7JEFPT BCPVU "%)%
coefficient, 32 t *OUFSBDUJWF TVSWFZT BOE BQQMJDBUJPO BDUJWJUJFT SFMBUFE UP "%)%
hyperactivity disorder perfect negative t *OUFSBDUJWF WFSTJPOT PG SFTPVSDFT JODMVEJOH UIF 4VNNBSZ 5FTU PO QBHFT
(ADHD), 27 42–43 and the critical thinking questions for the article on page 44.
case study, 28, 30 correlation coefficient, 32
case study, advantages, 35 perfect positive correlation CengageNOW!
case study, www.cengage.com/login
disadvantages, 35 coefficient, 32 Want to maximize your online study time? Take this easy-
centipedes, 31 placebo, 31 to-use study system’s diagnostic pre-test and it will create a personalized study
code of ethics, 40 placebo effect, 31 plan for you. e plan will help you identify the topics you need to understand
control group, 37 positive correlation better and direct you to relevant companion online resources that are specific
correlation, 32 to this book, speeding up your review of the module.
correlation and coefficient, 32
predictions, 33 questionnaire, 34 Introduction to Psychology Book Companion Website
correlation as clues, 33 random selection, 36 www.cengage.com/psychology/plotnik
correlation coefficient, 32 rhino horn, 31 Visit this book’s companion website for more resources to help you
correlation versus scientific method, 36 study, including learning objectives, additional quizzes, flash cards, updated
causation, 33 self-fulfilling prophecy, 30 links to useful websites, and a pronunciation glossary.
cough medication, 31 standardized test, 34
debriefing, 40 statistical procedures, 37 Study Guide and WebTutor
deception in survey, 28 Work through the corresponding module in your Study
experiments, 40 survey, advantages, 29 Guide for tips on how to study effectively and for help learning the material
dependent variable, 36 survey, disadvantages, 29 covered in the book. WebTutor (an online Study Tool accessed through your
double-blind procedure, 37 testimonial, 30 eResources account) provides an interactive version of the Study Guide.
experiment, 28, 36 tiger bones, 31
zero correlation, 32
Suggested Answers to Critical Thinking 4. Alcohol prevention programs should emphasize the immediate and
long-term negative health consequences resulting from adolescent
1. The three major methods for answering questions are survey, case binge drinking.
study, and experiment. In this study, researchers asked people
questions about their drinking and physical health, so this study 5. The advantage of this survey study is that it suggests an unex-
used the survey method. pected cause or explanation for why some young adults have
poorer health (adolescent binge drinking). One disadvantage of
2. Surveys cannot show cause-and-effect relationships but only cor- this survey study is that it cannot identify cause-and-effect
relations between events: teenagers who engaged in binge drinking relationships.
more often had poorer physical health as young adults than those
who engaged in binge drinking less often. To show a cause-and- 6. If he believes that binge drinking during adolescence causes later
effect relationship, this study would have to be designed as an health problems, he may behave in ways (worrying more, eating
experiment in which an experimental group got one treatment poorly) that cause the problems to occur. This error or bias is called
(alcohol) while a control group got no or different treatment (no a self-fulfilling prophecy.
alcohol/placebo).
L I N K S T O L E A R N I N G 45
3. This is difficult to know for certain. It may be helpful to examine
additional aspects of physical health (cholesterol level, family
history) and health behaviors (diet, routine medical care).
Brain’s
3 Building
Blocks
MODULE
48
Photo Credit: © Anatomical Travelogue/50
Photo Researchers, Inc.51
A. Overview: Human Brain 52 I. Application: Experimental Treatments 60
B. Neurons: Structure & Function 54 Summary Test 62
C. Neurons Versus Nerves 56 Critical Thinking 64
D. Sending Information 57
E. Transmitters 58 Mirrors in Your Brain? 65
F. Reflex Responses 59 Links to Learning
Concept Review
G. Research Focus: What Is a Phantom Limb? PowerStudy 4.5™
H. Cultural Diversity: Plants & Drugs Complete Module
46
Introduction
Losing One’s Mind Charles Schneider had an impressive He describes Alzheimer’s disease as a “cloud over
career—a police officer, firefighter, the brain. e simplest things take extreme effort”
Why does
Charles have and private investigator. He was also (C. Schneider, 2006b) (adapted from Fischman,
Post-it® Notes quite the craftsman, remodeling 2006; C. Schneider, 2006a).
everywhere? houses and building sturdy fences. For Charles, the worst is yet to come. His
He had a loving wife, two children, memory will fail, he will be bedridden, and
and five grandchildren. In his early fifties, Charles had he will not know who he is or be able to
everything he could ever want in life. recognize his family. When he dies—for
But that was before he started to forget things. Alzheimer’s has, at present, no cure—
What could explain why he could no longer Charles will have lost his memory, his
remember his lock combination at the firehouse wonderful personality, and all signs
or why he had to open every compartment in the of humanity.
firetruck to find the tools he needed? Why did the
names of his coworkers and other people he knew He had everything in life he could want
Diagnosis and Causesois9wbfwfawwtwhiawmUwenrashprean0moiiioeaatingertoeti%msdaofmnhlesshnaBIIreieolrnlndgalntendrt’dle(edeomsneedeao(oemNsi1mczifwAdstns,pgn0oaceItedaotcohHduigh%ghtmhailalurSaytfdoea,deluzenomymaatpoostt2ldarhe.toyenosanUeciru0aegheufnAerrkytsaewcg0ein,Cienies,tteohlso5eg,5pmhnhth.gsdrsepinihl,dhsreatOuteumosermfoteo2a.ieatwtue,fcvamocifwr0dnforh?Csseatihoadiii’t0hlnhcseetdwrbelauseWiuSeb8ahuldnnaveiaennsAian)etsl2r.tvbser.otdtAayg,gphhriT?s5e,prfe.nftiAeteaosyhmalenAocehsaBzriomnredrsnraslliencegphsiuozrzct,,nuraomoeehyidebehhltieeAlfnsyta,uireoeeatleosstomeeai,tewliilierepsilprfpnciolsdmremzityrneoehotflg.nnhhnaiioyceranegoveWloeg,hi’’aeoeflrensant,pursaein’isercil’dosn(2nhmsheltzsesduah6yoAide0oe,ecmrndld5eetrtataetnLo0peglih.eeihrhratscegrTms8leIfpen’hoCcyteoeeednso-;Smseobkhauiyrihata-tjciiesiieplhAenoatvnoadaeicpmifilernnltdrz-tolibnsagrshmpaedbce,el,hoelserateoctgeaosihfihmsmruloriisnyibocneastngmpdheib)swslf111ntgneuareusi528pidgsa’misnsm,rstate,sfi,sDaois,stoyr,gwtnbmeiuAewsmenhleirreclah.ylszheetimphusiaTothtcmiabyetighdfcreahnor.oeeeihetiefesmgmodirlalmsn5eiioppesmlnsepo0irrgrtibn’vlw’soos,aitsaiilveebbtslabywongoPw,rdtlluroeeal,iaaasvadhtotmmhhnnneeityeiieonddnddneessss-ntsthin1(vaobitnns2giApe6nnoLtigir0prhoahblddceaaezet0tysRclRuraruieiihe8safUevmnstaeirrdie)u.eaoiscSlsos.aidnssicsnue.ambemlAseueevlwa,lctydy,laieli2rcAlrsicplracise0trioosd’inlhhnissa0cnz(,swesbed8Wtdkhmcamnurioh;eielnsptoserSulooeriieefmsmbknftbltdasiyfaydeetrnfiieosceiarioaela,enhnnrhrirlgvfie,’y2eendogfbcdb((sfenlcvwtoSMar0.ialaleiysahtoevoiaocenru0chntms&efitappAgtIag6socdiinAoamnhnipcneui)aorernlgLcthsc.sdelazgssgismhCzapgesoyce,Wbahoeeieh(olAoehag2vrnAbAfceamcecpslnaaac0iiluiivArsiyhilltazominran0iofizlemrehnthlmme(ilul7arhedlic,dzpesmcevvreste)ste2hop,rrlieg.ienee’h(rcisomo0o’e2idtaMeDsm’stocedsgosicn00tnts,dmea.sogeeeriamo9e0Re&bffierlniurNfonsr;n8ste’nuuIessf’egofanSi)screWrs.,atgtt.asmbn’kuboews(iiacisRnaoycAvetdwdmlaestauthcnd,renehnetiirlwlaldrnaceddrzlnletiagtPeinetsyeeekeiheehvtm,tpp,nEanavnluaneiete2itlAdfletoeTtotoiprtiry&0yamgtmpllriwsoertlaoyasf0ilzs,atalapruny,cLeipec8ohiairneltrkdainrtegna)ei,gleevnmdh’nr.lieotnsisntiettetgcFsmcecsghephssrhAeaen)laraoa,sebiaonrauetetessnlsterprerrrslt,retsyrhsdccieaehp’tesuasoocsadmbahhaa,ix.ansalrcnnoetcieut2eeoa7pesspildmsflaeor0asmg0dibetttdaeubiseetc0prroic–neratidisvecpscio8aaotoan7mmdaaeeaeeeul)yiorgn1steli.nnnddddlerssss----)f,,,until he developed Alzheimer’s.
Cheng, 2008). e number of patientsPhoto Credit: © Jeffrey MacMillan/U.S. News & World Report9 What’s Coming
is projected to rise dramatically in Millions 6
the coming decades (right graph) as 3 3.7 e reason Alzheimer’s disease will eventually
people are expected to live longer. It is destroy Charles’s memory, personality, and
estimated that nearly half of those over 0 humanity is that it gradually destroys the
age 85 have Alzheimer’s (Alzheimer’s 1990 2010 2030 2050 building blocks that form the brain’s informa-
(projection)
Association, 2007). tional network. We’ll explain the two groups
Charles is an example of how someone in his fi ies can develop of brain cells—glial cells and neurons—that make up this network.
Alzheimer’s disease, which is o en incorrectly associated only with We’ll discuss how the cells in one group—neurons—have a remark-
elderly people. As expected with this devastating disease, his condi- able ability to receive and send information. You’ll discover how
tion is worsening over time. Charles is never without a pen and pad brain cells communicate with chemicals that have the ability to
to write down things to not forget, and he has Post-it Notes with start or stop the f low of information. Finally, we’ll explain an
written reminders in his pockets and placed throughout his house. experimental treatment of implanting neurons to treat brain dis-
These notes are a tremendous help in getting Charles through eases. We’ll use the story of Charles and Alzheimer’s disease to
his day. He now has trouble completing even very simple tasks. illustrate the brain’s building blocks.
I N T R O D U C T I O N 47
A. Overview: Human Brain
As Alzheimer’s disease slowly destroys Charles’s brain, he is also We’ll use Charles’s brain and his current problems with
slowly losing his mind. In Charles’s case, Alzheimer’s disease has Alzheimer’s disease to answer four related questions: Why
progressed to the point that he can no longer get through his day isn’t the brain a nose? What’s in the brain? Can a brain
without Post-it Note reminders placed throughout his house. grow new neurons? Can you take a picture of the mind?
Development of the Brain Structure of the Brain
e fact that your brain does not develop On the right is a top view
Why isn’t the into a nose is because of instructions What’s in of a human brain. It is
brain a nose? contained in your genes.
your brain? shaped like a small wrin-
Genes are chains of chemicals arranged kled melon, weighs about
like rungs on a twisting ladder (right figure). There are about 20,000– 1,350 grams (less than 3 pounds), has a pinkish-
25,000 genes that contain chemical instructions white color, and has the consistency of firm
equal to about 300,000 pages of typed instructions JELL-O®. Your brain is fueled by sugar (glucose)
(IHGSC, 2004). The chemical instructions in the and has about 1 trillion cells that can be divided
genes program the development of millions of indi- into two groups—glial cells and neurons. Top view of
vidual parts into a complex body and brain. Glial Cells. e most numerous human brain
An amazing feature of the 20,000–25,000 brain cells, about 900 billion, are called glial
genes is they are contained in a fertilized egg, (GLEE-all) cells.
which is a single cell about the size of a grain of Glial cells (astrocytes) have at least three functions:
sand. We’ll explain more about the genes and
their chemical instructions in the next module providing scaffolding to guide the growth of developing
(see p. 68).
neurons and support mature neurons; wrapping around
In the brain’s early stages of development,
it looks nothing like the final product. For neurons to form insulation to prevent interference from
example, the figure below looks more like
some strange animal than what it really is, a Glial cell other electrical signals; and releasing chemicals that
six-week-old human embryo with a developing influence a neuron’s growth and function (Verkhratsky &
brain.
Chemical Butt, 2007).
instructions
Glial cells grow throughout one’s lifetime. If something causes the
32 Six-Week-Old Brain. is drawing uncontrolled growth of glial cells, the result is brain cancer. Until Photo Credits: top, © Jeffrey MacMillan/U.S. News & World Report; top right, Wadsworth Publishing
1 represents a greatly enlarged six-week-old recently, glial cells were believed to have only supportive functions
human embryo. e 3 labeled areas (in (as described above), but research now shows some glial cells may
3 colors) will eventually develop into the transmit electrical signals, which is the major function of neurons,
3 major divisions of the mature human which we’ll discuss next (Leitzell, 2008; Saey, 2008b).
brain that is shown below.
Neurons. e second group of brain cells, which
number about 100 billion, are called neurons
(NER-ons); one is shown on the right.
Mature Brain. e 3 labeled areas A neuron is a brain cell with two specialized exten-
3 major divisions of represent the 3 major divisions of the
6-week-old brain mature brain that we’ll discuss in the sions. One extension is for receiving electrical signals, and a
next module. e mature second, longer extension is for transmitting electrical signals.
Back human brain (side view) Depending upon their size, neurons receive and
1 weighs almost 3 pounds transmit electrical signals at speeds of up to 200 miles
and contains about 1 per hour over distances from a fraction of an inch to over
3 feet, such as from your toe to your spinal cord.
trillion cells (Ropper & Neurons form a vast, miniaturized informational
Samuels, 2009).
2 network that allows us to receive sensory informa-
3 In the case of Charles, tion, control muscle movement, regulate digestion,
Front who developed Alzheimer’s secrete hormones, and engage in complex mental
disease, researchers think processes such as thinking, imagining, dreaming, Neuron
3 major divisions some of his genetic instruc- and remembering.
of adult brain tions were faulty. The faulty Charles’s brain was constructed from two kinds of building
instructions resulted in an blocks—glial cells and neurons. However, it is the neurons that
abnormal buildup in the brain of gluelike substances that grad- Alzheimer’s disease gradually destroys; the result is that Charles’s
ually destroy brain cells (Cheng, 2008; Sergo, 2008). Next, we’ll brain is losing its ability to transmit information, causing memory
explain the two different kinds of brain cells and which ones are and cognitive difficulties. Why neurons do not usually repair or
destroyed by Alzheimer’s disease. replace themselves is our next topic.
48 M O D U L E 3 B R A I N ’ S B U I L D I N G B L O C K S
Growth of New Neurons Brain Versus Mind
If you had a bird’s brain, you could grow As Alzheimer’s disease destroys Charles’s
Can a brain new neurons every spring. A male canary Can you take brain, he is also losing his mind, which
a picture of brings us to the mind-body question.
grow new learns to sing a breeding song in the spring, the mind?
The mind-body question asks how com-
neurons? but when breeding season is over, the ability
to sing the song disappears. However, come plex mental activities, such as feeling, think-
The two red dots show two next spring, an adult canary’s ing, and learning, can be explained by the physical, chemical, and
areas of the mature canary’s
brain that increase by 50% with brain begins growing about 20,000 electrical activities of the brain.
the growth of new neurons. new neurons a day, and, during
this short period, the bird relearns rough the centuries, philosophers and scientists have given
the breeding song. ese new neu- different answers to the mind-body question, some believing the
rons result in a 50% or more increase mind and brain are separate things and others saying the mind
in neurons in two areas of the canary’s and brain are one and the same (Hergenhahn, 2009).
brain (le figure) that control singing
(G. Miller, 2003). Without a doubt, an For example, Nobel Prize winner and geneticist Francis Crick
adult canary’s brain can regularly grow (2002) believes the mind is the brain: “You, your joys and your
new neurons (Kim et al., 2008). sorrows, your memories and your ambition, your sense of per-
sonal identity and free will, are in fact no more than the behavior
Primate Brains. Does the fact that adult canaries as well as adult of a vast assembly of nerve cells and their associated molecules.”
mice, rats, and other animals can grow new neurons also hold true Although some agree with Crick’s answer—that the mind and
for adult human brains (Barinaga, 2003)? Researchers believe that, brain are the same—others reply that mental activities cannot be
with few exceptions, the brains of adult primates, such as humans reduced to the physical activities of the brain (Mahoney, 2005).
Photo Credit: right, Courtesy of Center on Aging and Department of Molecular and Medical Pharmacology, University of California, Los Angeles and chimpanzees, develop almost all their neurons at birth and
adult brains do not grow new neurons (Kornack & Rakic, 2001). Another answer comes from Nobel Prize winner and neuro-
The few exceptions to the finding that physiologist Roger Sperry (1993), who said that the brain is like a
Growth of new neurons new neurons do not grow in adult brains coin with two sides. One side consists of physical reactions, such
is found in this area of were found in two areas of the brain— as making chemicals that neurons use for communicating. e
hippocampus (p. 80) and olfactory bulb other side consists of all of our mental functions, such as think-
the mature human ing, imagining, and deciding. According to Sperry, the brain’s
brain (hippocampus). chemicals (physical side) inf luence consciousness and mental
activities, which, in turn, influence the production of more or dif-
(p. 107). Researchers concluded that adult ferent brain chemicals. ere is considerable support for Sperry’s
monkey and human brains are capable idea of continuous interaction between the physical and mental
of growing a relatively limited num- sides (Dolan, 2007).
ber of new neurons throughout
adulthood and that some of these
new neurons play an important Alzheimer’s. In Charles’s case, as Alz- Normal Brain
role in our continuing ability to heimer’s disease destroys his brain, he
also loses more and more of his mental
learn and remember new things activities, such as knowing, thinking,
(S. Halpern, 2008; Saey, 2008c).
and deciding. Researchers can study a
Repairing the Brain. Besides having a limited capacity to grow person’s mental activities by taking
new neurons throughout adulthood, mature human brains also brain scans of the neural activities going
have a limited capacity to replace, rewire, or repair damaged neu- on inside the living brain (brain scans
rons, such as a er a stroke, gunshot wound, or blow to the head are discussed on pp. 70–71). For exam-
(SFN, 2007; J. Silver & Miller, 2004). One reason neurons have ple, the top right brain scan shows a
only a limited capacity to be repaired or rewired a er damage is great amount of neural activity occur-
that there is a genetic program that turns off regrowth when neu- ring inside a normal brain (red/yellow
rons become fully grown (Aamodt & Wong, 2008; McKerracher & indicate most neural activity, blue/green Alzheimer’s Brain
Ellezam, 2002). is limited capacity of the adult brain to rewire
itself by forming new connections helps explain why people may indicate least activity). In comparison,
recover some, but rarely all, of the functions initially lost after the bottom right brain scan shows rela-
brain damage. Recent advances in stem cell research suggest the tively little neural activity and thus rela-
human brain may be able to grow more neurons. If this were pos- tively little mental activity occurring
sible, the brain could repair damage caused by an accident or dis- inside an Alzheimer’s brain. ese kinds
ease, such as Alzheimer’s (Wieloch & Nikolich, 2006). of brain scans show that neural activi-
ties and mental activities are closely
e reason Alzheimer’s disease is so destructive and eventually linked, and researchers are studying
leads to death is that this disease destroys neurons many times how these links occur (E. L. Diamond et
faster than the brain’s limited capacity for regrowth, repair, or al., 2007; Mosconi et al., 2005).
rewiring. As Alzheimer’s destroys Charles’s brain, what is happen- Knowing now how important neurons are to your mental and
ing to his mind? physical functions, we next examine them in more detail.
A . O V E R V I E W : H U M A N B R A I N 49
B. Neurons: Structure & Function
Parts of the Neuron Before Charles developed Alzheimer’s disease, he was able to engage in an incredible variety of cognitive
and physical behaviors. He was able to think, remember, walk, smile, and speak—all because of the activity
Why could of millions of microscopic brain cells called neurons. We’ll examine the neuron, which comes in many
Charles think, wondrous shapes and sizes and has only three basic structures—cell body, dendrites, and axon.
move, and talk?
Signals travel away from the
cell body, down the axon.
1 The cell body 2 Dendrites (DEN- 3 The axon 4 The myelin 5 End bulbs or 6 The synapse Photo Credit: © Alfred Pasika/SPL/Photo Researchers, Inc.
(or soma) is a drites) are branchlike (AXE-on) is a single (MY-lin) sheath terminal bulbs (SIN-apse) is an
relatively large, extensions that arise threadlike structure looks like separate look like tiny bub- infinitely small space
egg-shaped struc- from the cell body; they that extends from, tubelike segments bles that are locat- (20–30 billionths of
ture that provides receive signals from and carries signals composed of fatty ed at the extreme a meter) that exists
fuel, manufactures other neurons, muscles, away from, the cell material that wraps ends of the axon’s between an end bulb
chemicals, and or sense organs and body to neighboring around and insulates branches. Each end and its adjacent body
maintains the pass these signals to neurons, organs, or an axon. The myelin bulb is like a minia- organ (heart), muscles
entire neuron in the cell body. muscles. sheath prevents ture container that (head), or cell body.
working order. interference from stores chemicals
At the time of Here the axon electrical signals called neurotrans- When stimulated
In the center birth, a neuron has is indicated by generated in adjacent mitters, which are by electrical signals
of the cell body few dendrites. A er an orange line axons. used to communi- from the axon,
is a small oval birth, dendrites inside the tube cate with neighbor- the end bulbs eject
shape represent- undergo dramatic composed of e axons of ing cells. neurotransmitters
ing the nucleus, growth that accounts separate gray most large neu- into the synapse.
which contains for much of the segments. Axons rons, including End bulbs
genetic instruc- increase in brain vary in length motor neurons, reach right up e neurotrans-
tions (in the size. As dendrites from less than a have myelin to, but do not mitters cross the
form of DNA) grow, they make hair’s breadth to sheaths. You may physically touch, synapse and act
for both the connections and as long as 3 feet have heard the the surface of like switches to
manufacture of form communication (from your spinal brain described as a neighboring turn adjacent
chemicals and networks between cord to your toes). consisting of gray organ (heart), cells on or off.
the regulation neurons and other An axon conducts and white matter. muscle (head), or We’ll explain this
of the neuron. cells or organs. electrical signals Gray is the color of another cell body. switching process
to a neighboring cell bodies, while a little later.
organ (heart), white is the color
a muscle, or of myelin sheaths.
another neuron.
Alzheimer’s Disease and Neurons In Alzheimer’s disease there is an excessive buildup of gluelike substances, which
gradually destroy neurons (Larson, 2008). In Charles’s case, these gluelike substances
Alzheimer’s Size of normal will destroy many of his neurons, causing his brain to actually shrink, as shown by the
brain is brain with all very deep creases in the Alzheimer’s brain (le photo). Researchers have been testing
smaller of its neurons experimental vaccines that may help stop and prevent the buildup of these killer sub-
because it intact. stances, and they continue to search for other interventions (Reinberg, 2008).
has lost many
neurons. We have discussed the structure and function of neurons, but it is important not
to confuse neurons (in your brain and spinal cord) with nerves (in your body).
50 M O D U L E 3 B R A I N ’ S B U I L D I N G B L O C K S
C. Neurons Versus Nerves
Reattaching Limbs John Thompson was 18 when a Transplanting a Face In 2005, French doctors performed
farm machine ripped off both of the world’s first-ever face transplant,
What’s unusual Can parts of your
about John’s arms? his arms just below his shoulders. face be transplanted a very risky and complex procedure.
Since he was home alone, he had to onto someone else’s? Doctors removed facial tissue from a
walk to the farmhouse, open the front door with his mouth, and dead woman’s face and transplanted
with a pencil clenched in his teeth, dial the phone for help. When it onto Isabelle, a 38-year-old woman whose face had been severely
paramedics arrived, he reminded them to disfigured by a dog. She received a new nose, lips, and chin during the
get his two arms, which were still stuck in surgery (Gorman, 2005b). A few months a er the surgery, Isabelle
the farm equipment. John was taken to said, “I can open my mouth and eat. I feel my
the hospital, where doctors reattached lips, my nose and my mouth” (Doland, 2006).
both arms (indicated by red arrows in Her ability to experience facial sensations
le photo). and control facial muscles continues to
Three months later, John could improve now years later. ere is still the
raise his arms up but could not move risk her body will reject the donor’s facial
them below his elbows. A er several tissue (it has already done so twice), but so
years of physical therapy and 20 oper- far the surgery has been a great success
Both his arms were torn ations, John can raise his reattached (R. Weiss, 2007).
off and then reattached. arms over his head, make fists, and The fact that severed nerves in arms,
grip with his hands. John must constantly work at maintain- hands, or face can be reattached but neurons
ing mobility and strength in his arms ( ompson & Grosinger, in a severed spinal cord are difficult to reat- Isabelle with makeup
2001). In another case, a donor hand was attached to the arm of a tach illustrates a major difference between one year after face
person whose own hand was severed (B. Bower, 2008d). the peripheral and central nervous systems. transplant.
Photo Credits: top right, © CHU Amiens/Getty Images; top left, © Taro Yamasaki; bottom right, © AP Images/Jennifer Graylock Peripheral Nervous System Central Nervous System
Severed limbs can be reat- People may have numbness or paralysis a er damage to their
Why can tached and regain movement Why do brain or spinal cord because of what neurons cannot easily do.
Montel’s
limbs be and sensation because their feet hurt? The central nervous system is made up of neurons located in the
reattached? nerves are part of the periph- brain and spinal cord (shown in blue in left figure).
eral nervous system. e adult human brain has a limited capac-
The peripheral nervous system is made up of nerves, ity to grow new neurons and to make new connections. Once dam-
which are located throughout the body aged, neurons usually die and are not replaced.
except in the brain and spinal cord. Because neurons have a limited capacity for repair and regrowth,
Nerves are stringlike bundles of people who have an injured or damaged brain or spinal cord expe-
axons and dendrites that come from rience some loss of sensation and motor movement, depending
the spinal cord and are held togeth- upon the severity of the damage. For example, Montel Wil-
er by connective tissue (shown in liams (right photo), a former television talk-show host, has suf- Montel was
diagnosed with
orange in right figure). Nerves carry fered from pain in his feet and legs for many years as a result multiple sclerosis.
of multiple sclerosis, a disease that attacks the myelin sheaths that
information from the senses, skin, wrap around and insulate cells in the central nervous system.
muscles, and the body’s organs to
and from the spinal cord. Nerves in As a result of this damage, messages between the brain and other parts of the
body are disrupted, o en causing problems in motor coordination, strength, and
the peripheral nervous system Peripheral nerves sensation (Pirko & Noseworthy, 2007).
have the ability to regrow or reat- can be reattached.
tach if severed or damaged. Currently, one of the most exciting areas of research involves techniques that
stimulate the regrowth or repair of damaged neurons. For example, axons, which
e fact that nerves can regrow means that sev- carry information up and down the spinal cord, normally wither and die a er inju-
ered limbs can be reattached and limb transplants ry. Two methods to promote the regrowth of axons are providing tubes that guide
are possible. However, limb transplants are risky their growth and injecting growth-producing chemicals (M. E. Schwab, 2002). e
because a person must take drugs long-term to sup- newest approach for treating brain damage is to replace damaged neurons by trans-
press his or her own immune system, whose normal planting fetal tissue or stem cells (taken from embyros) into the damaged area.
job is to destroy “foreign” things, such as a donor’s
transplanted limb. When his or her own immune is method has great potential for treating brain and spinal cord diseases, such
system is suppressed, a person is at risk for getting as Alzheimer’s and multiple sclerosis (Karussis & Kassis, 2007; A. M. Wong et al.,
serious infectious diseases (Lake et al., 2007). 2005). We’ll discuss stem cell transplants in the Application section.
e remarkable ability of nerves to regrow and Now that you know the structure of the neuron, we’ll explain one of its amazing
be reattached distinguishes them from neurons. functions: sending information at speeds approaching 200 miles per hour.
C . N E U R O N S V E R S U S N E R V E S 51
D. Sending Information
Sequence: Action Potential 2 Axon Membrane: Chemical Gates 3 Ions: Charged Particles
e fluid inside and outside the axon
1 Feeling a Sharp Object Just as a battery has a protective covering, so contains ions.
too does the axon. ink of an axon as a long
When you step on a sharp object, Ions are chemical particles that have electrical
you seem to feel the pain almost tube that is not only filled with charges. Ions follow two rules: Opposite charges
immediately because neurons fluid but also surrounded with
send signals at speeds approach- fluid. e axon’s tube is formed attract (figure below), and like charges repel.
ing 200 mph. To feel the pain
involves the following series of by a thin membrane, similar to a S(oNdAiu+m) Opposite Protein
electrochemical events: battery’s outside cover- ions charges ions
A. Some stimulus, such as a tack, ing, which keeps the attract
fluid separate and
causes a change in physical also has special gates. e fluid contains several different ions,
energy. e tack produces such as sodium, potassium, chloride, and
mechanical pressure on the The axon membrane has protein. e axon’s function is o en explained
bottom of your foot. chemical gates (shown in red) by discussing sodium and potassium ions.
B. Your skin has sensors that pick that can open to allow electri- However, it is simpler and easier to focus on
up the mechanical pressure just sodium ions, which have positive charges
and transform it into electrical cally charged particles to enter and are abbreviated Na+, and large protein
signals. (We’ll discuss various or can close to keep out elec- ions, which have negative charges and are
kinds of sensors in Module 5.) trically charged particles. labeled protein−. Because they have opposite
C. e sensors’ electrical signals charges, Na+ ions will be attracted to protein−
are sent by the neuron’s axon to Just as a ions (figure above).
various areas in the spinal cord battery’s power
and brain. comes from Axon Because the axon’s membrane separates the
D. Finally, your brain interprets positive sodium ions from the negative protein
these electrical signals as “pain.” its electrically ions, we have the makings of a living battery, as
We’re going to focus on step C charged chemi- shown in section 4 on the next page.
and explain how axons send cals, so does the axon’s
electrical signals by using the power to send informa-
analogy of a battery. We’ll begin tion. In fact, the axon’s
by enlarging the inside of an axon. Gates
electrically charged particles
are the key to making it a living battery.
Sequence: Nerve Impulse 7 All-or-None Law 8 Nerve Impulse
6 Sending Information Why does a nerve Notice in this drawing, which continues on the next
impulse travel down page, that the nerve impulse is made up of a sequence
One mistake students make is to think that the the axon’s entire length? of six action potentials, with the first action potential
axon has ONE action potential, similar to the occurring at the beginning of the axon.
bang of a gunshot. However, unlike a gunshot, e answer is the all-or-
the axon has numerous individual action poten- none law. 1. Action
tials that move down the axon, segment by seg- potential
ment; this movement is called the nerve impulse. The all-or-none law
says that, if an action
The nerve impulse refers to the series of separate potential starts at the
action potentials that take place segment by segment beginning of an axon, the
action potential will contin-
as they move down the length of an axon. ue at the same speed, seg-
us, instead of a single bang, a nerve impulse ment by segment, to the
very end of the axon.
goes down the length of the axon very much
like a lit fuse. Once lit, a fuse doesn’t go off in a You’ll see how the
single bang but rather burns continuously until all-or-none law works in
it reaches the end. is movement of a nerve the next figure.
impulse all the way down to the end of an axon
is actually a natural law.
52 M O D U L E 3 B R A I N ’ S B U I L D I N G B L O C K S
4 Resting State: Charged Battery 5 Action Potential: Sending Information
e axon membrane separates positively charged sodium If a stimulus, such as stepping on a tack, is large enough to excite a neuron,
ions on the outside from negatively charged protein ions on two things will happen to its axon. First, the stimulus will eventually
the inside. is separation produces a miniature chemical open the axon’s chemical gates by stopping the sodium pump. Second,
battery that is not yet discharging and, thus, is said to be when the stoppage of the sodium pump causes the gates to open, thou-
in its resting state. sands of positive sodium ions will rush inside because of their attraction
The resting state means to the negative protein ions. e rush of sodium ions inside the axon is
Sodium that the axon has a charge, called the action potential.
(NA+) The action potential is a tiny electric current that is generated when the
ions or potential; it resembles a
battery. The charge, or positive sodium ions rush inside the axon. The enormous increase of sodium ions
potential, results from the inside the axon causes the inside of the axon to reverse its charge. The inside
axon membrane separating becomes positive, while the outside becomes negative.
5a Just as a current flows when you
positive ions on the outside
connect the poles of a battery, current
from negative ions on the Action Potential
inside (left figure). also flows when sodium ions rush
e axon membrane through the opened gates of the
has a charge across it
during the resting state 5baxon membrane.
because of several factors, the primary one being the sodi- During an action potential, the
um pump. (To simplify our explanation of the resting state, inside of the axon changes to positive
we won’t discuss other pump or transport systems.) and the outside changes to negative.
The sodium pump is a transport process that picks up any Inside = positive Immediately a er the action potential,
sodium ions that enter the axon’s chemical gates and returns the sodium pump starts up and returns
them back outside. Thus, the sodium pump is responsible for ––––––– the axon to the resting state.
Outside = negative At this point, imagine that an action
keeping the axon charged by returning and keeping sodium ions
outside the axon membrane. potential has started at the beginning
In the resting state, the axon is similar to a fully of an axon. How action potentials whiz at race-car speeds down the
charged battery. Let’s see what happens when the resting entire length of an axon is what we’ll examine next in the section below,
state is disrupted and the battery discharges. Sequence: Nerve Impulse.
8a According to the all-or-none 8b Notice that the 9 End Bulbs and Neurotransmitters
myelin sheath has regu- Once the nerve impulse reaches the end of the axon, the very last action
law, once a nerve impulse begins, lar breaks where the axon potential, 6, affects the end bulbs, which are located at the very end of
it goes to the end of the axon. is is bare and uninsulated. the axon. is last action potential triggers the end bulbs to release their
means that when action potential It is at these bare points neurotransmitters. Once released, neurotransmitters cross the synapse
1 occurs, it will be followed in that the axon’s gates open and, depending upon the kind, they will either excite or inhibit the
order by potentials 2, 3, 4, 5, and the action potential function of neighboring organs (heart), muscles (head), or cell bodies.
and 6. A er the occurrence of takes place. As you can now see,
each action potential, the axon neurotransmitters are
membrane at that point quickly critical for communicat-
returns to its resting state. Breaks in myelin ing with neighboring
organs, muscles, and
other neurons. We’ll
examine transmitters
in more detail and show
2. Action 3. Action 4. Action 5. Action 6. Action you how they excite
potential potential potential potential potential or inhibit.
D . S E N D I N G I N F O R M A T I O N 53
E. Transmitters
Excitatory and Inhibitory Neurotransmitters
ere’s no doubt that you have felt your Writing a paper on a computer requires
What makes heart pounding when you are afraid, What makes your brain to use millions of neurons that
your heart stressed, or angry. One reason for your your brain communicate with one another by using
pound? pounding heart has to do with work? chemicals called neurotransmitters.
transmitters. Neurotransmitters What happens
A transmitter is a chemical messenger that are about a dozen different chemicals that are in my brain
carries information between nerves and body organs, Why does my made by neurons and then used for communication when I use my
heart rate computer?
such as muscles and heart. increase when between neurons during the performance of
Everything you do, including
I get angry? mental or physical activities.
thinking, deciding, talking,
and getting angry, involves Since billions of neurons that are
transmitters. For example, packed tightly together use differ-
imagine seeing someone ent neurotransmitters for eating,
back into your brand new sleeping, talking, thinking, and
car and then just drive away. dreaming, why don’t neurotrans-
You would certainly become mitters get all mixed up? e
angry and your heart would pound. answer is that neurotransmitters
Let’s see why getting angry can increase your heart rate from a are similar to chemical keys that fit
normal 60 to 70 beats per minute to over 180. into only specific chemical locks.
1 In the figure on the le , 1 e figure on the le again
you see the end of an axon
with 3 branches. At the shows the end of an axon with
end of the bottom branch 3 branches. We have again
is a greatly enlarged end enlarged one end bulb to
bulb. Inside the bulb are show that it contains neuro-
4 colored circles that transmitters (4 colored circles).
represent transmitters. 2 e action potential
2 When the action Transmitters causes the end bulbs to Neurotransmitters
potential hits the end bulb, it eject their neurotransmit-
causes a miniature explosion, ters (yellow circles), which, Receptors
and the transmitters are ejected in turn, cross the synapse
outside. Once ejected, transmitters and, in this case, land on the
cross a tiny space, or synapse, and, in surface of nearby dendrites.
this case, reach the nearby heart muscle. e surface of one dendrite is
ink of transmitters as chemical keys enlarged (right figure) to show
that fit into chemical locks on the surface its receptors (white notches),
of the heart muscle. End bulbs usually which are special areas that Receptors on dendrites
Transmitters can function like chemical locks. are like chemical locks.
hold either excitatory or inhibitory trans- increase or decrease
mitters, which have opposite effects. heart rate. 3 Although there are many different neurotransmitters, each
3 Strong emotions cause the release of excitatory transmitters, one has a unique chemical key that fits and opens only certain
which open chemical locks in the heart muscle and cause it to chemical locks, or receptors. us, billions of neurons use this
beat faster (le figure). When you get very angry, system of chemical keys that open or close matching locks to
excitatory transmitters may cause your heart rate communicate and to participate in so many different activities.
to double or even triple its rate. When you start to Also, remember that some neurotransmitters are excitatory—
calm down, there is a release of inhibitory trans- they open receptor locks and
mitters, which block chemical locks in the heart turn on neurons—while others
Excitatory muscle and decrease its rate (right are inhibitory—they close locks
figure). ink of transmitters acting like chemical and turn off neurons.
messengers that either excite or inhibit nearby Since neurons use neurotransmitters to communicate, any
body organs (heart), neurons, or muscle fibers. drug that acts like or interferes with neurotransmitters has the
One special class of transmitters that are made potential to change how the brain functions and how we feel,
in the brain are called neurotransmitters. Inhibitory think, and behave. For example, here’s what alcohol does.
54 M O D U L E 3 B R A I N ’ S B U I L D I N G B L O C K S
Alcohol New Transmitters
Drinking alcoholic beverages usually raises ere are a number of well-known neuro-
What does the level of alcohol in the blood, which is What are transmitters, such as norepinephrine,
alcohol do? measured in terms of blood alcohol content the latest GABA, dopamine, and serotonin. And
(BAC). For example, at low to medium discoveries? researchers continue to discover new ones
doses (0.01–0.06 BAC), alcohol causes friendliness, loss of inhibi- to add to the list of neurotransmitters.
tions, decreased self-control, and impaired social judgment; a er Endorphins. In the 1970s, researchers discovered the brain
3 or 4 drinks, the average person’s BAC makes its own painkiller, very similar to morphine. ey called
will range from 0.08 to 0.1, this neurotransmitter endorphin, which is secreted to decrease
Why do I feel which meets the legal defini- pain during great bodily stress, such as an accident (Drolet et al.,
different after tion of drunkenness in most 2001). We’ll discuss the effects of endorphins on page 113.
states. (Alcohol is discussed Anandamide. In the early 1990s, researchers
drinking?
more fully in Module 8.) discovered a somewhat surprising neuro-
Alcohol (ethyl alcohol) is a psychoactive transmitter, called anandamide, which
drug that is classified as a depressant, is similar in chemical makeup to THC,
which means that it depresses the activity the active ingredient in marijuana
of the central nervous system. (discussed on p. 186) (Fackelmann,
Photo Credits: top right, Courtesy of Miles Herkenham, PhD, Section of Functional Neuroanatomy, NIMH; bottom right, Courtesy of Johns Hopkins University, Alcohol has been around for 1993). e figure on the right shows
Office of Public Affairs 3,000 years, but researchers have only a horizontal section of a rat brain
recently determined its many effects treated with a radioactive version of
on the brain. We’ll discuss one of its anandamide. e yellow areas, which
major effects on the brain. were most affected by anandamide, are
GABA neurons. Alcohol involved in memory, motor coordina-
affects the nervous system in tion, and emotions (Herkenham, 1996).
a number of ways, blocking Anandamide may help people regulate Yellow areas show
some neural receptors and emotions, which would help them better where marijuana-like
stimulating others. For example, cope with anxiety and stress (Moreira &
anandamide acts.
some neurons are excited by a Lutz, 2008).
neurotransmitter called GABA Nitric oxide. In the mid-1990s, researchers discovered that a
(GAH-bah), which the brain gas, nitric oxide, functions like a neurotransmitter and may regu-
normally manufactures. is means that GABA neurons (figure late emotions. For example, mice genetically
above) have chemical locks that can be opened by chemical keys altered to lack nitric oxide were
in the form of the neurotransmitter GABA (Purves et al., 2008). six times more likely to pick
GABA keys. Now here’s the interesting part. Alcohol molecules a fight compared to normal
so closely resemble those of the GABA neurotransmitter that mice (R. J. Nelson et al.,
alcohol can function like GABA keys and open GABA receptors 1995). Researchers believe
(figure right). Opening GABA receptors excites GABA neurons. nitric oxide may regulate
Although it seems backward, when GABA neurons are excited, aggressive and impulsive
they decrease neural activity and produce inhibitory effects, such behaviors not only in mice
as a loss of inhibitions and self-control, as well as reduced anxiety. but also in humans (Chiave- Changing neurotransmitter levels in
In fact, one reason alcohol has gatto et al., 2006). rats causes increased aggression.
become so popular is that Alcohol mimics Orexin (hypocretin). In the late 1990s, researchers discovered
many people drink alcohol to neurotransmitter. orexin (hypocretin), a neurotransmitter involved in the brain’s
feel less anxious and more pleasure and reward system. In animal studies, researchers could
relaxed. It is interesting initiate or reduce cravings for drugs and food by activating or
that there appears to be a blocking orexin (G. C. Harris et al., 2005). Orexin is also involved
biological link between in regulating sleep and wakefulness. For instance, low levels of
alcohol and anxiety. this neurotransmitter have been linked to a serious sleep disorder
Researchers found that a called narcolepsy (discussed on p. 163) (Sakurai, 2007).
deficiency in a specific brain The important point to remember about neurotransmitters
protein is associated with GABA receptor is their system of chemical keys and locks permits very effective
high anxiety and excessive communication among billions of neurons, which allow us to
alcohol use (Wand, 2005). move, sense, think, feel, and perform hundreds of other functions.
We learned that alcohol affects the brain by imitating a natu- Now that you are familiar with neurons and neurotransmitters,
rally occurring neurotransmitter, GABA. Let’s now look at the we’ll explain a response that many of you have experienced—what
effects other drugs have on the brain’s neurotransmitters. happened when you touched a hot object.
E . T R A N S M I T T E R S 55
F. Reflex Responses
Definition and Sequence
Can you move If you accidentally touched a hot light In some cases, such as when a doctor taps your knee, the knee-
without bulb, your hand would instantly jerk away, jerk reflex is controlled by the spinal cord. In other cases, such as
without any conscious thought or effort on when someone shines a bright light into your eye, the pupillary
thinking? your part. is is an example of a reflex. reflex causes the pupil to constrict. We are all born with a number
of programmed reflexes, and all reflexes share the same two or three
A reflex is an unlearned, involuntary reac- steps, depending upon how they are wired in the nervous system.
tion to some stimulus. The neural connections or network underlying a One reason reflexes occur so quickly is that they are geneti-
cally programmed and involve relatively few neural connections,
reflex is prewired by genetic instructions.
which saves time. Here’s the sequence for how a reflex occurs:
1 Sensors. e skin of your fingers has specialized sen-
sors, or receptors, that are sensitive to heat. When you
touch a hot light bulb, these skin sensors trigger neurons that
start the withdrawal reflex.
2 Afferent neuron. From the receptors in your skin, long den-
drites carry “pain information” in the form of electrical signals to
the spinal cord. ese dendrites are part of sensory, or afferent,
Efferent, neurons (red arrows).
or motor,
neuron Afferent (AFF-er-ent), or sensory, neurons carry information from the
3. Interneuron senses to the spinal cord.
makes connections Sensory neurons may have dendrites 2 to 3 feet long, to reach
between neurons,
which carry from the tips of your fingers to the spinal cord. When the pain infor-
message to mation enters the spinal cord, it is transmitted to a second neuron.
the brain.
3 Interneuron. Once the afferent neuron reaches the spinal cord, it trans-
Afferent, mits the pain information to a second neuron, called an interneuron.
or sensory, An interneuron is a relatively short neuron whose primary task is making con-
neuron nections between other neurons.
In this example, an interneuron transmits the pain information to a
third neuron, called the efferent, or motor, neuron.
4 Efferent neuron. Inside the spinal cord, an interneuron transfers infor-
mation to a third neuron, called an efferent, or motor, neuron (blue
arrows).
Efferent (EFF-er-ent), or motor, neurons carry information away from the spinal
4. Efferent, or motor, cord to produce responses in various muscles and organs throughout the body.
neuron carries neural From the spinal cord, an efferent (motor) neuron sends electrical signals
messages from spinal
cord to hand. on its 2- to 3-foot-long axon to the muscles in the hand. ese electrical
signals contain “movement information” and cause the hand to withdraw
quickly and without any thought on your part.
In addition, an interneuron will send the pain information to other neu-
rons that speed this information to different parts of the brain. ese different
parts interpret the electrical signals coming from your hand as being hot and
2. Afferent, or sensory, neuron painful. At this point your brain may direct motor neurons to move your facial
carries neural messages from and vocal muscles so that you look pained and yell “Ouch!” or something much
hand to spinal cord.
Functions of a Reflex more intense.
e primary reason you automatically withdraw your hand when primitive reflex that is no longer useful in our modern times is
touching a hot object, turn your head in the direction of a loud noise, called piloerection, which causes the hair to stand up on your arms
or vomit a er eating tainted food has to do with survival. Reflexes, when you are cold. Piloerection helped keep heat in by fluffing hair
which have evolved through millions of years, protect body parts for better insulation, but clothes now do a better job.
from injury and harm and automatically regulate physiological
responses, such as heart rate, respiration, and blood pressure. One A er the Concept Review, we’ll discuss a very strange neural
phenomenon that you may have heard of—phantom limb.
56 M O D U L E 3 B R A I N ’ S B U I L D I N G B L O C K S
Concept Review
1. The structure that nourishes and maintains 5. The end bulbs of one neuron are sepa-
the entire neuron is the (a) . rated from the dendrites of a neighboring
Branchlike extensions that receive signals neuron by an extremely small space
from senses and the environment are called called the (a) . Into this
(b) . A single threadlike space, end bulbs release chemicals, called
extension that speeds signals away from the (b) , which open/excite
cell body toward a neighboring cell is the or block/inhibit neighboring receptors.
(c) . A tubelike structure
that insulates the axon from interference by 6. From end bulbs, chemical keys or (a)
are secreted into the synapse. These chemical keys
neighboring signals is the (d) . open matching locks called (b) ,
Tiny swellings at the very end of the axon are
called (e) , which store neuro- which are located on the surface of neighboring
dendrites, muscles, or organs. Neurotransmitters
transmitters. that open a receptor’s lock are called (c) ;
2. Chemicals that have electrical charges are neurotransmitters that block a receptor’s lock are called
called (a) . They obey the rule (d) .
that opposite charges attract and like charges
repel. Although the fluid of the axon contains a 7. Neurons in the brain and spinal cord make up
the (a) . If neurons are damaged,
number of ions, we have focused on only two, they have little ability to (b) and
a positively charged (b) ion,
whose symbol is Na+, and a negatively charged usually die. The mature human brain has a limit-
ed ability to regrow (c) through-
(c) ion. out adulthood. Information from the body’s
3. If an axon membrane has a potential senses, skin, organs, and muscles is carried to and
similar to a charged battery, the axon is in the from the spinal cord by nerves that make up the
(a) . During this state, the ions (d) . If this nervous system is
outside the membrane are positively charged damaged, (e) in this system
(b) ions; the ions inside have a remarkable ability to regrow and make
the membrane are negatively charged new connections. If your finger were accidentally
(c) ions. cut off, it could be (f) and there
is a good chance that your finger would regain
4. If an axon membrane is in a state most of its sensory and motor functions.
similar to a discharging battery, the axon
is generating an (a) . 8. If you touch a sharp object, your hand auto-
During this potential, the chemical matically withdraws because of a prewired
gates open and positively charged reflex response. Neurons that carry “pain
(b) rush inside, information” to the spinal cord are called
changing the inside of the membrane (a) neurons. Inside
to a (c) charge, while the spinal cord, there are short neu-
the outside of the membrane has a rons, called (b) , that
(d) charge. As the action potential moves down make connections between other neu-
the axon, it is called an (e) . Once it is generated, rons that carry information to the
the impulse travels from the beginning to the end of the axon; this brain. Neurons that carry information away from the spinal cord
phenomenon is referred to as the (f) . to muscles or organs are called (c) neurons.
Answers: 1. (a) cell body or soma, (b) dendrites, (c) axon, (d) myelin sheath, (e) end bulbs; 2. (a) ions, (b) sodium, (c) protein; 3. (a) resting state,
(b) sodium, (c) protein; 4. (a) action potential, (b) sodium ions, (c) positive, (d) negative, (e) impulse, or nerve impulse, (f) all-or-none law;
5. (a) synapse, (b) neurotransmitters; 6. (a) neurotransmitters, (b) receptors, (c) excitatory, (d) inhibitory; 7. (a) central nervous system, (b) regrow,
repair, or reconnect, (c) neurons, (d) peripheral nervous system, (e) nerves, (f) reattached; 8. (a) sensory, or afferent, (b) interneurons, (c) motor, or
efferent
C O N C E P T R E V I E W 57
G. Research Focus: What Is a Phantom Limb?
Case Study
Why does A puzzling question for researchers smashing my toes with a hammer.” He goes on to say,
Christian feel to answer is: How can someone “On the pain scale of one to 10, I’d say it was a six or
feel a phantom limb? a seven. But then again, my ‘10’ is getting both of
pain in his This question applies to Sgt. my legs blown off” (Bagge, 2006).
missing toes? Christian Bagge, who was hit by Despite frequent episodes of excruciating pain,
two roadside bombs in Iraq. The Christian wants to do everything he did before the
next thing he remembers is waking up in a hospital with one injury. With the use of his artificial legs (le photo),
leg amputated above the knee and the other below the knee. he is doing just that. For instance, one year a er his
He didn’t realize the worst of his condition until a short while injury, Christian ran side by side with former President
later when he suddenly felt a crushing pain in his toes (which George W. Bush (Gehlert, 2006). Don-
were no longer there!) (Bierma & Woolston, 2006). Christian Christian feels “real” ald’s case introduces you to the strange
describes the intense pain by saying it “feels like someone is pain coming from his phenomenon of phantom limb.
amputated legs.
Definition and Data
What is Very few symptoms have so surprised doc- ing from their removed limbs (A. Hill et al., 1996). In other cases,
tors as when patients reported feeling strange amputees felt their removed limbs were not only still present but
phantom sensations or movements in arms or legs that stuck in certain positions, such as permanently twisted in a spiral,
Photo Credit: top, © Getty Images
limb? had been amputated, a phenomenon called painfully pinned to their backs, or sticking straight out from their Figure/Text Credit: Based on an illustration in Scientific American Mind, April/May, 2006, p. 18 by Jason Lee. By permission of Jason Lee.
phantom limb. bodies, so they felt they had to be careful
Phantom limb refers to feeling sensations or Patients’ Reports after Removal of Limbs not to hit their phantom limbs when going
movements coming from a limb that has been through doorways (Katz & Melzack, 2003;
amputated. The sensations and movements are Report Sensations 80−100% Nicolelis, 2007).
extremely vivid, as if the limb were still present. Scientists have been struggling for
As the graph on the right shows, the Report Pain 70−80% many years to better understand what
vast majority of individuals feel sensations causes the feelings of sensations and
(“pins and needles”) or intense pain com- movements coming from phantom limbs.
Answers and Treatment Treatment. One interesting treatment method has been to create an
illusion that the phantom limb exists. is has been done by having
Answers. Early researchers thought the phantom limb sensations people with amputations of the arm and phantom limb pain place
came from cut nerves remaining in the stump or from the spinal their arm inside a mirror box. Looking into the
cord. Researchers now believe the origin of phantom limb sensa- box, they see the reverse image of
tions must be the brain itself (Purves et al., 2008). But, researchers their remaining arm on the mirror,
are puzzled about how the brain generates these sensations. rather than a missing limb (right
photo). By helping patients rec-
The newest and most supported answer about the origin of reate a complete body image,
phantom limb sensations comes from researcher Ronald Melzack, the use of mirrors has had
who has been studying this problem for over 40 years (Melzack, some success in reducing
1989, 1997). He states that each of us has a genetically programmed phantom pain in lower and
system of sensations that results in our knowing where our body upper limb amputations
parts are and in our developing an image of our body. Based on (Brodie et al., 2007; Chan et
sensations from body parts, Melzack believes the brain pieces al., 2007; Maclachlan et al.,
together a complete body image. us, having a body image, the 2003). Researchers are also investigat- This mirror box can help to
brain can generate sensations as coming from any body part, even reduce phantom limb pain.
if that part is a phantom limb. With time, the brain can correct its
representation of the body to acknowledge the loss of a limb, which ing the effectiveness of virtual reality
could explain why phantom sensation is most severe at first and in reducing phantom limb pain (C. D. Murray et al., 2006, 2007).
then decreases in intensity over time (Purves et al., 2008). e phantom limb phenomenon points out that the brain some-
times functions in mysterious ways. Less mysterious is how certain
Because traditional medical treatment has had limited success drugs affect the functioning of the brain and the body.
in treating phantom limb pain, researchers are looking for more
creative and effective treatments (Nicolelis, 2007).
58 M O D U L E 3 B R A I N ’ S B U I L D I N G B L O C K S
H. Cultural Diversity: Plants & Drugs
Where did e very first drugs that affected neurotransmitters came from various plants, which
the first drugs people used long before researchers knew what those plants contained. We’ll discuss
three such drugs—cocaine, curare, and mescaline—which come from plants found in
come from? different parts of the world. We’ll explain what these plants contain and their actions on
the nervous systems.
Cocaine: Blocking Reuptake Reuptake is a process through which some neurotransmitters,
For almost 3,500 years, South American Indians have such as dopamine, are removed from the synapse by being trans-
chewed leaves of the coca plant. Following this
ancient custom, adult Indians habitually carry ported back into the end bulbs.
bags of toasted coca leaves, which contain cocaine.
If reuptake does not occur, the released neuro-
roughout the day, they chew small amounts of transmitter would continually affect the neuron by
coca leaves to relieve fatigue and feelings of hun- remaining longer in the synapse. What cocaine does is
ger. Here’s how cocaine affects neurotransmitters. block reuptake so that dopamine remains longer in the
Cocaine blocks synapse (Huang et al., 2007). Because cocaine blocks
e drawing on the right shows a neuron’s end reuptake.
bulb containing the neurotransmitter dopamine
(DOPE-ah-mean). Once released, dopamine (orange reuptake, neurons are stimulated longer, resulting in
circles) reaches the dendrite’s receptors, opens the physiological arousal and feelings of euphoria that
Photo Credits: top, Adalberto Rios Szal Sol/PhotoDisc; center, © Borys Malkin/Anthro-Photo; bottom, © G.I. Bernard/Animals, Animals/Earth Sciences their chemical locks, and activates the neuron. are associated with cocaine usage. Researchers now
However, after a short period of time, the neu- understand why South American Indians chewed coca
rotransmitter is normally removed by being trans- leaves. e cocaine released from chewing coca leaves
ported back into the end bulb through a process blocked the reuptake of dopamine, which in turn caused
called reuptake. Cocaine works by physiological arousal that relieved fatigue and feelings
blocking reuptake. of hunger.
Curare: Blocking Receptors Curare is an example of a drug that stops neural transmis-
sion by blocking the muscles’ receptors. Today, the purified
When hunting animals, the Indians of Peru and active ingredient in curare (tubocurarine chloride)
Ecuador coat the ends of blowdarts with the juice of is used to induce muscle paralysis in humans,
a tropical vine that contains the paralyzing drug such as when doctors insert a breathing tube
curare. down a patient’s throat. Curare doesn’t easily
enter the brain because the body’s blood must go
Curare (cure-RAH-ree) is a drug that enters the blood- through a filtering system before it can enter the
stream, reaches the muscles, and blocks receptors on brain. is filtering system, called the blood-brain
barrier, prevents some, but not all, potentially
muscles. As a result, the neurotransmitter that normally Why did Indians coat harmful substances in the body’s blood supply
blowdarts with curare? from reaching the brain.
activates muscles, which is called acetylcholine, is blocked,
and muscles are paralyzed (M. R. Lee, 2005).
Once hit by a curare-tipped blowdart, an animal’s limb
muscles become paralyzed, followed by paralysis of chest
muscles used to breathe.
Mescaline: Mimicking a Neurotransmitter eat from 4 to 12 peyote buttons, which results in visual sen-
A golf-ball-sized, gray-green plant (right photo) called peyote
cactus grows in Mexico and the southwestern United States. sations, euphoria, and sometimes nausea and vomiting.
Peyote contains mescaline (J. H. Halpern et al., 2005). Conclusion. ese three plants—cocaine, curare,
Mescaline (MESS-ka-lin) is a drug that causes physiological and mescaline —contain potent drugs that illus-
arousal as well as visual hallucinations. Mescaline’s chemical trate three different ways of affecting the nervous
keys are similar to those of the neurotransmitter norepinephrine system. Researchers have discovered numerous
(nor-epee-NEFF-rin). plants, including the opium poppy, marijuana, and
Because mescaline’s chemical keys open the same chemi- Mescaline comes “magic” mushrooms, that contain drugs that in turn
cal locks (receptors) as norepinephrine, mescaline produces from peyote cactus. affect neurotransmitters (discussed in Module 8).
its effects by mimicking the actions of norepinephrine. Neurotransmitters are the keys that turn the
In 1965, an estimated 250,000 members of the Native American brain’s functions on or off. For example, Alzheimer’s disease inter-
Church in the United States and Canada won a Supreme Court case feres with neurons and neurotransmitters and turns off the brain’s
that permits them to be the only group legally authorized to use pey- functions. Such is the case with another terrible disease, called
ote in their religious services. To enhance meditation, members may Parkinson’s, which we’ll discuss next.
H . C U L T U R A L D I V E R S I T Y : P L A N T S & D R U G S 59