What is Cognitive Psychology?

• Broad Definition –empirical investigation of mental events and knowledge involved in recognizing an object, remembering a name, having an idea, understanding a sentence, and solving a problem

• Specific Definition - the empirical investigation of mental processes and activities used in perceiving, remembering, and thinking, and the act of using those processes.

• “Pay attention!” – Concept: Attention -- how we filter or select important information

from the environment.

• “I don’t know.”– Concept: Knowledge -- the store of general information and

algorithms for performing tasks.

• “I don’t remember.”– Concept: Memory -- a process for storing, retrieving and working

with information.

• “I can’t decide.”– Concept: Decision making – set of higher-level processes that

work together allow us function day to day

History of Cognitive Psychology

• Early history – Philosophical roots– Socrates – interested in the origins of

knowledge

– Aristotle – interested in origins of knowledge & memory

• Proposed first theory of memory– Descartes – how is knowledge represented

mentally

History of

• Recent history – Psychological roots– Wilhelm Wundt (1879)

• First psychological laboratory in Leipzig, GE– Founder of psychology as a science– Many early psychologists had roots in Wundts lab

» Produced over 200 Ph.D students in philosophy and psychology

• Topic: Human cognition– Used introspection to report contents of consciousness

History of

– Edward Titchner• Student of Wundts, taught at Cornell University in

1892– Proponent of introspection– Narrow view of psychology

» Excluded mental illness, education apps., and social psych, b/c not open to introspection

» Note: Method defined what was allowable science– Founder of Structuralism

» Study of: Sensations, images, and feelings that were elements of the mind

– Often argued with Wundt over findings

History of

– Herman von Ebbinghaus• Contemporary of Wundt in GE

– Big influence on cognitive psych.– Developed method for studying forgetting as function of time

» Stimuli: lists of Consonant-Vowel-Consonant’s (CVC’s)» Method: Learn list of CVC’s, count number of trials to

recall perfectly Wait 2 days re-learn list.» Savings score = # of trials to learn the 1st time - # of trials to

learn 2nd time– One subject entire career – himself– Learned over 40,000 CVC’s

History of

– William James• Wundt’s student, hired at Harvard

– Philosopher, but started first American psych. lab• Proposed Functionalism

– Stressed the functions over the mind rather than contents» How does mind adapt to new circumstances?» Proposed multicomponent memory system: Primary

Memory vs. Secondary memory– Authored: Principles of Psychology, chapters on

Sensation, perception, attention, consciousness, memory, reasoning

History of

• Modern History– Human Performance (WWII)

• Attention and perception, – training of solders to use radio and radar

• Signal detection– Blips on radar or sonar

• Information theory – – abstract method for analyzing information processing

History of

– Artificial intelligence• How can we make computers behave intelligently?• Contributed host of concepts

– Idea of study machine, allowed us to study our own processes

– Linguistics• Interested language and language development• Contributed new mode of analyzing structure of

language

Emergence of Cognitive Psychology

• 1950’s – 1970’s, no agreed upon date• Ulric Neisser’s “Cognitive Psychology” text

published in 1967• Why did Cog. Psyc emerge?

– Two major factors• Dissatisfaction w/ behaviorism’s account of complex behavior

(e.g., Chompsky’s new model of language)• Convergence of several other fields during WWII

– Linguistics, Human performance, AI

Contributors to Cog. Psych

• Human Performance– Abstract way to analyze processing of info.

(development of psychological tools!)– Research ideas in attention and perceptions

• AI– Idea of computer as info. Processor– Computer model – Tool for studying cognition– Focus on complex processing (decision making,

reasoning)

Contributors to Cog. Psych

• Linguistics & Verbal learning– Questions about language and its complexity– Reason to reject behaviorism

• Complexities of lang. Not handled by behaviorism

• Philosophy– Age old questions about knowledge and Memory

• Behaviorism– Strong empirical methods and laboratory research

Summary• Cog. Psych began with Wundt

– Cognitive issues of mental states– But, introspection method not strong

• Replication difficult, methodology determined acceptable sub-disciplines

• These problems fueled behaviorist movement

• Behaviorism was major paradigm from 1910’s to 1960’s– Focus shifted to overt behavior

• Stimulus response• Mind considered a black box, can’t study what you can’t see,

hear, feel, or touch– Psychologists need reason to abandon behaviorism

• Linguistic’s criticisms provided the stimulus

Summary• War time efforts - scientists from different fields

came together for one purpose– Focus on attention and perception– Expansion of methodological toolboxes

• Enabled Psychologist to go beyond S-R psych.– Idea of humans as “Active” info. Processors

• Contrast with behaviorism – Organisms respond to environment

• Invention of computer & focus on mental processes• Chompsky’s review of Skinner’s book on language

– Illuminated inadequacies of behaviorism

Cognitive Psychology

• Information processing approach – decomposition of mental processes– Multi-component memory system

• Assumptions of Cog. Psych.– Mental processes exist– People are active information processors– Mental processes and structures can be revealed

by time and accuracy measures

EnvironmentalStimuli

SensoryMemory

Short-term / WorkingMemory

Long-term Memory&

KnowledgeCognitivePsychology

is concerned withwhat goes on in here.

Overt ResponseBehavior

Info. Processing model

Component of Model

• Sensory memory – input device– What info is sent to the processor

• Short-term / Working memory– Central processor, actively processes info

• Long-term memory / Knowledge– Library of programs, algorithms, data, and

experiences that are stored for use†Note similarities to computer!

Sternberg Paradigm

• Test of how info is processed • Subjects (Ss) memorize list of digits

{4, 6, 5, 9, 3, 2}• Given recognition test

9?Yes/No

• Measure both accuracy and reaction time (Msec.)Some trials were false (8?)Some were true (9?)

Think in terms of Memory system!

9 65932

4LTMSTM / WM

--

+-

--

Decision

Results

350

400

450

500

550

600

650

0 2 4 6 8

String size

Mse

c

Perceive Stimulus

Generate response

Make decision

9=9? 9=3?

9=6? 9=2?

Perceive Stimulus

Generate response

Make decision

7=9? 7=3?7=6? 7=2?

6, 9, 3, 2

9?

7?

What would happen if the search string were 6 items?

What would happen if degraded the probe?

What would happen if we biased the decision process?

• Time to respond was linear function of size of search string– Each element added 38 msec to search time

• Serial position did not matter!– Thus, search is exhaustive

• Sternberg’s conclusion: Ss engaged in serial matching process