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!” “I don’t know.” “I don’t remember.” “I can’t decide.” 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 Linguistics 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

Info. Processing model Short-term / Working Memory Sensory Memory Overt Response Behavior Environmental Stimuli Long-term Memory & Knowledge Cognitive Psychology is concerned with what goes on in here.

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 LTM - 4 - 6 9 - 5 + 9 - 3 - 2 Decision

Results

What would happen if the search string were 6 items? 6, 9, 3, 2 9? Perceive Stimulus 9=3? 9=2? Make decision Generate response 9=6? 9=9? 7? Perceive Stimulus Make decision Generate response 7=6? 7=9? 7=3? 7=2? 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