PSY 323: Cognition

Chapter 1: Introduction to Cognitive Psychology

Cognition and Cognitive Psychology• Cognition• The mental processes that are involved in

perception, attention, memory, problem solving, reasoning, and making decisions

• Cognitive Psychology• Branch of psychology concerned with the

scientific study of cognition

Challenges of Cognitive Ψ

• Often times, “the processes involved in cognition are complex and hidden from view”• Take a moment and think about all that is

happening around you (perception, attention, memory, reasoning)

History of Cognitive Ψ:1st Cognitive Psychology Experiment• Donders (1868)• Franciscus Donders, Dutch physiologist• Measured reaction time: time b/w presentation of stimulus and

person’s response to that stimulus• Simple reaction time• The length of time it takes to push a button after the

presentation of a stimulus • Choice reaction time • Push one of two buttons in response to a stimulus

• Inferred mental process of perception• Mental response cannot be measured directly, but can be

inferred from behavior (choice reaction time – simple reaction time = length of time to make a decision)

• All research in cognitive psychology deals with inferred mental processes

A pioneer of the scientific study of memory:Hermann Ebbinghaus (1850 – 1909)

• Worked as philosopher at University in Berlin• Performed experiments on himself published in classic

volume entitled: ‘Über das Gedächtnis’ (1885)

Memory experiments of Ebbinghaus:Focus on retention of newly learned material

• Invented lists of 16 nonsense syllables to minimize influence of meaningful associations and learner’s history

• His goal: study memory in ‘pure’ form

• Introduced criterion for successful learning

Hermann Ebbinghaus

• Ebbinghaus founded the experimental study of memory• Serial Learning Experiments • A list of items presented one at a time; you must recall them in

order• Memorizing lists in sequence until they can be recalled perfectly• Ran tests on himself for six years• Memorized thousands of lists of nonsense syllables (ZAB, VUB,

etc.)• Invented 2300 of these syllables, arranged them in random lists

and tested them after various delays

• What problems do you see with this methodology?

Ebbinghaus' Experiments

• Serial Learning Experiments• Learning to criterion

• Ebbinghaus would repeatedly attempt to learn the material until he achieved a perfect reproduction (every item memorized in the order originally presented)

• “Method of savings“• Subtracting the number of repetitions required to relearn material to a

criterion from the number originally required to learn the material to the same criterion

• Savings = (Initial Repetitions – Relearning Repetitions)/ Initial Repetitions

• List-length effect• Ease of learning and amount of information not related in linear one-to-

one fashion• Disproportionate increase in difficulty with more than 7 syllables

• Distributed practice• Beneficial effects of distributed practice for repetitions

Ebbinghaus' Experiments: Important Findings

• Forgetting Curve• Recollection of words drops dramatically during the first

hour of learning

Ebbinghaus' Experiments: Important Findings

Structuralism

• Wilhelm Wundt• 1879, founded first laboratory of scientific psychology at the

University of Leipzig, in order to study the mind scientifically• Carried out reaction-time experiments• Developed analytic introspection• Procedure used in which trained participants described their

experiences and thought processes elicited by stimuli presented under controlled conditions

• Problematic: introspection did not seem to reveal the structure of thought; results from different laboratories often disagreed

Abandoning the study of the mind…• Behaviorism• John Watson

• Developed new approach to psychology by studying actual behaviors in their own right and not worrying about consciousness

• Argued behavior is observable and objective

• Studied impact of stimulus conditions on behavior (stimulus-response)

• Most famous study: Little Albert

Abandoning the study of the mind…• Behaviorism• B.F. Skinner

• Studied operant conditioning: believe reinforcements, not free will, determined behavior

• Published book on verbal behavior that claimed language developed through imitation and reinforcement

Reemergence of the mind…• Cognitive Learning• Focus on the role of thinking processes in learning• Theory based on unseen internal factors rather than

on external factors

Latent Learning

• Tolman and Honzik (1930)• Took three groups of rats and had them run a maze

• Group 1 • Reinforced every time they found their way out of the maze

(food box) for ten days• Group 2 • Never reinforced (no food at the end)

• Group 3 • Reinforced only after day 10 of the experiment

Latent Learning• On day 11, they timed the three groups to see

which group would make it through the maze the quickest…• Which group do you think was the fastest?

Cognitive Psychology• Scientific study of mental processes• Simply put “it is the study of thought”• Behavior is examined by cognitive psychologists the same way

that physicists infer the force of gravity from the behavior of objects in the world.

• Mental Processes: remembering, attention, producing and understanding language, solving problems, and making decisions

• Thinking is something that is constantly happening, yet we rarely stop to think about it

Cognitive Processes

• Perception and Sensory Memory• Organize and interpret incoming information (e.g., first

lecture)• Sensory memory holds information, like an information buffer,

just long enough to determine whether it seems worthwhile• Attention• Set of processes through which you focus on incoming

information• Ability to attend is flexible—can divert (cocktail party effect,

police car)• Attention is also limited

Rebirth of Study of the Mind

• Cognitive Science• Study of the mind (mental processes) as carried out by many

different disciplines• Disciplines: cognitive psychology, and research on the mind

within the fields of computer science, linguistics, neuroscience, anthropology, artificial intelligence, and philosophy

Modern Approaches to Study the Mind

• Behavioral Approach• Measure behavior and explain cognition in terms of

behavior• e.g., reaction time• Measuring mental rotation exercise

Modern Approaches to Study the Mind

• Physiological Approach• Measure both behavior

and physiology and explain cognition in terms of physiology

• e.g., reaction time and brain wave activity or brain activation

• Davachi experiment (words that were remembered on the memory test had more brain activity when words were first exposed

Models of the Mind:Introduction of Digital Computer

• Flow Diagrams for the Mind• Rise of the Information Processing Metaphor• Broadbent’s flow diagram depicted the mind as processing

information in a sequences of stages• Information processing models conceive of cognitive activities as

involving a series of steps, procedures, or processes that take time (e.g., 1/10 second)

Credits

• Some slides of this presentation prepared with the help of the following websites:• www.cogsci.rpi.edu/courses/cogpsy/spr09/lectures/Chapter%201.ppt