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 subdisciplines
• 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
Info. Processing model
Environmental
Stimuli
Cognitive
Psychology
is concerned with
what goes on in here.
Sensory
Memory
Short-term /
Working
Memory
Long-term Memory
&
Knowledge
Overt
Response
Behavior
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!
STM / WM
+
-
9
Decision
4
6
5
9
3
2
LTM
Results
650
600
Msec
550
500
450
400
350
0
2
4
String size
6
8
6, 9, 3, 2
9?
Perceive
Stimulus
9=6?
9=9?
9=3
?
9=2
?
Make
decision
Generate
response
7?
Perceive
Stimulus
7=6?
7=9?
7=3?
7=2?
Make
decision
Generate
response
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