Historical Foundations of Cognitive Psychology - Colorado

Historical Foundations of Cognitive Psychology
Cognitive Psychology
• A Definition
• Tim Curran
• [email protected] – The scientific study of mental processes such as
• Lecture slides are available at: perceiving, remembering, using language,
reasoning, and solving problems.
http://psych.colorado.edu/~tcurran/oreilly.html
• The formal discipline of “Cognitive
* BUT YOU SHOULD STILL TAKE NOTES! Psychology” started in the mid-1900’s.

• Read Chapter 1 in Text • It’s roots can be traced back much further.

Greek Philosophers Later Philosophy
)(4th-5th Century BC
(1600s - 1800’s)
– Influential figures: Plato & Aristotle
– Began to consider questions about perception, memory, • Nativism (since Plato)

and thought. – Knowledge is innate
• heredity, nature
• Plato = Rationalist
• Empiricism
– Emphasized logical analysis.
– Influential figures: Hobbes & Locke
• Aristotle = Empiricist – Knowledge is gained through experience

– Emphasized observations of the external world. • learning, nurture
– Associationism
– Specific assumptions, allowing for tractable questions:
• Knowledge originates from interconnected information.
• The world can be understood and predicted.
• Humans are part of that world. – BANNANA-YELLOW-FRUIT-PEEL-LONG
• Explanations should be of this world.
• Key principle of modern “neural network” models.

• Compromise Positions

– Influential figures: Descartes & Kant
– Both Nurture and Nature are important.

Influence of Philosophy on German Physicists
Cognitive Psychology
(1800s)
• Contribution to Cognitive Psychology • Influential figures:

– Identified many fundamental questions and • Helmholtz: Color vision
assumptions about the nature of the mind. • Fechner: Psychophysics

• Limitations • Relationship between physical changes in stimuli
and sensory experience.
– Lacked scientific methods.
• Applied scientific methods.
Early Scientific Psychology • Contribution to Cognitive Psychology

• Structuralism • Use of scientific/experimental methods.
• Functionalism
• Behaviorism • Limitation

• Limited to the study of simple sensory processes.

Structuralism

• Influential figure: Wilhelm Wundt
• Focus on identifying the basic building blocks

of conscious experience.

• Analogy with periodic table of elements in chemistry.

• Main method: "Introspection" under controlled
conditions.

• Contribution to Cognitive Psychology

– Emphasized systematic, controlled observation.
– Importance of the understanding the structure of the

mind, and higher cognitive processes.

• Limitation

– Reliance on introspection.

Functionalism Behaviorism

• Influential figure: William James • Influential figures: John B. Watson, B. F. Skinner
• Mental processes must be adaptive, so what are • Guiding Principles:

they good for? – Only focus on that which is observable.
– Explain behavior; not thought, consciousness, etc.
– e.g., practical uses and functions – Theories should be simple.
– Inspired by evolutionary theory. – Break down behavior into irreducible constructs.

• Main methods: • Main method: Rigorous experimentation
• Contribution to Cognitive Psychology
– Introspection, questionnaires, mental tests, animal
experiments – Emphasis on rigorous experimentation.

• Contribution to Cognitive Psychology – Powerful theories of learning

– Emphasis on the functions and applications. • Classical Conditioning

• Limitation – Learning relationships among stimuli.

– Methods not very rigorous. – e.g., Pavlov’s dog learned relationship between bell and food.

Limitations of Behaviorism • Operant Conditioning

• Failures to account for aspects – Learning responses that are rewarded.
of human behavior
– e.g., A dog learns to sit for a treat.
– Over-emphasis on animal experimentation
– Language • Failure to consider intervening mental processes

• Skinner suggested language was learned through basic – Behaviorism:
principles of operant conditioning.
Stimuli Responses
– i.e., we learn to say what is rewarded
– Cognitive Psychology
• Fails to account for Generativity of language.
Stimuli Mental Processes Responses
– The creation of novel utterances
that have never been rewarded in the past. – Stimulus (memorize this list)

– e.g., Chomsky (linguist) • lion, onion, Bill, firefighter, carrot,
zebra, John, clerk, Tim, nurse, cow

– Response (recall)

• lion, zebra, cow, onion, carrot,
firefighter, clerk , nurse, John, Bill, Tim

– Mental Processes

• Strategies, grouping, reorganization, etc.

Overview of Different Approaches

Stimuli Mental Processes Responses Outside Influences in mid 1990’s

•Philosophy • Interest in optimizing human performance

•Argue about mental processes – World War II

•Introspection • Computer Science

•Directly tap into mental processes – Artificial Intelligence
– Computer Metaphor
•Behaviorism
• Information processing, memory buffers, etc.
•Study stimulus-response relationships
•Ignore mental processes Information Processing Analysis Example

•Cognitive Psychology

•Study stimulus-response relationships
•Make inferences about mental processes

Information Processing

• The dominant approach toward studying human
cognition.

• Decomposing a cognitive task into a set of abstract
information processing steps.

• Designing experiments to understand the
characteristics of each stage.

Representations & Processes Sternberg’s Memory Scanning Task

• A representation is a symbol for an entity in http://coglab.psych.purdue.edu/coglab/
the real world.

– e.g., computers represent numbers in a binary code
• “8” = “0-1-1”

• A process manipulates/transforms
representations in some way.

– e.g., addition, multiplication, etc

Information Processing Stages Possible Search Processes
in the Memory Scanning Task
1. Serial, Exhaustive Search
Search
Memory – Whole letter set is always searched, one by one.

• RT increases with set size, and Yes = No

Encode Decide Respond

L AKLM L Yes = /
? No = z

AKLM

(stages during probe recognition phase)

Possible Search Processes Possible Search Processes

2. Serial, Self-terminating Search 3. Parallel Search

– Letters searched one by one until target is found or – All letters in set simultaneously identified.
search is complete.
• RT unaffected by set size or yes/no.
• RT increases with set size, but faster for “yes” responses
because search stops when the target is found in the set.

Encode Search Decide Respond Summary of Information

Sternberg’s Results Processing Approach

• Serial Exhaustive Search • Decomposing a cognitive task into a set of
abstract information processing stages.
– Search rate inferred from slope =
38 ms per item • Attempts to understand
processes/representations within each stage.
• Encoding/Decision/Response
Stages • A given stage (e.g., memory search) can be
studied by manipulating variables (e.g., set
– Combined speed is y-intercept size) hypothesized to affect that stage, and
= 397 ms observing performance (e.g., reaction time).

– Don’t vary with set size

– Vary with variables that should
affect these processes.