Transcript Power Point 1

Cognition Psyc33000 Professor N. Rader
The Basics
•Who’s Who in the class –
Professor Rader
Teaching Assistant Ted Alhanti
attendance, class photos and info sheet
•Notebook – Why a notebook and how its organized
Paying for the Notebook -- $5 in envelope with your name
•Syllabus – Highlights
•Calendar – Its organization and how to use it
What is Cognitive Psychology ?
How to study the mind?
Some history
• Wundt & Mental Chronometry
• Introspection
• Gestalt Psychology
• Behaviorism
Paradigmatic Shift Leading to Modern Day Cognitive Psychology
How did this shift come about?????
Wundt and Mental Chronometry
Wilhelm Wundt
(1832-1920)
In attempting to resolve disputes amongst
astronomers who had written down different
times on their star maps for positioning stars,
Wundt suggested that the differences were
caused by differences in the speed of mental
processes. He believed it would be possible to
explain differences in behavior by measuring how
long it took people to respond to stimuli. Hence
was born the reaction time experiment.
Important in Wundt’s lab were a number of
devices used to measure reaction time.
Introspection as an Approach to Studying the Mind
William James was a proponent of functionalism, which refers to a
general psychological philosophy that considers mental life and
behavior in terms of active adaptation to the person's environment.
Functionalism was a philosophy opposing the prevailing structuralism
of psychology of the late 19th century.
William James “Introspective Observation is what we have to rely on first and foremost and
(1842-1910)
always. The word introspection need hardly be defined—it means, of course, the
looking into our own minds and reporting what we there discover.”
Edward Titchener, the main structuralist, gave psychology its first
definition as a science as the study of mental experience, of
consciousness to be studied by trained introspection. Titchener
founded the 1st psych lab in the U.S. at Cornell University.
E.B. Titchener
(1867-1927
In order to make psychology scientific we must not only describe, we
must also explain mind. We must answer the question “why.”
Titchener’s brain in
the Wilder Brain
Collection at Cornell
Gestalt Psychology
“The whole is more than the sum of its parts.”
The Gestalt Psychologists observed that what
people saw in simple drawings was not just
descriptive of what was on the page. Instead, there
were “emergent properties” such as seeing certain
lines or textures as belonging together to form a
whole. They attempted to explain these emergent
properties by identifying “laws of organization”.
They believed that what was seen was mirrored in the
pattern of neural activity in the brain; this idea is
known as “isomorphism”.
The overarching law was know as the “Law of Pragnanz”, which stated that observers
would see whatever was the “best” organization. Other laws included the Law of
Similarity, the Law of Proximity, the Law of Good Continuation, & the Law of Closure.
As a precursor to Cognitive Psychology, the
Gestalt Psychology approach was important in
that it demonstrated that
internal processes
were important in explaining behavior.
Unfortunately, they were unable to describe
these internal processes other than with the
faulty idea of
isomorphism
Enter Behaviorism
John B. Watson
1878 - 1958
Watson established the approach known as behaviorism
after doing research on animal behavior. Watson put the
emphasis on external behavior of people and their
reactions on given situations, rather than the internal,
mental state of those people. In his opinion, the analysis of
behaviors and reactions was the only objective method to
get insight in the human actions.
Tabula rasa =
Mind blank at birth and
contents added through
experience
Watson’s Little Albert experiment (1920) provided empirical
evidence of classical conditioning in humans and demonstrated
stimulus generalization. Based on his view that children had an
innate fear to loud noises, he used classical conditioning to create
in Little Albert a fear of anything white and furry.
Classical Conditioning
Before Training
UCS (noise)
CS (white rat)
UCR (fear)
No relevant response
Training
CS (white rat) + UCS (noise)
After training (i.e., conditioning)
CS (white rat)
CR (fear)
From Watson’s article of 1913, "Psychology as the Behaviorist Views It“
— sometimes called "The Behaviorist Manifesto"
“Psychology as the behaviorist views it is a purely objective
experimental branch of natural science. Its theoretical goal is the
prediction and control of behavior. Introspection forms no
essential part of its methods, nor is the scientific value of its data
dependent upon the readiness with which they lend themselves
to interpretation in terms of consciousness. The behaviorist, in
his efforts to get a unitary scheme of animal response,
recognizes no dividing line between man and brute.”
Consciousness is an
“epiphenomenon”, meaning it
accompanies behavior but has
no significance in itself for
understanding behavior.
Behaviorism becomes the dominant approach to Psychology
Its heyday is the 1950’s and 60’s
Focus on observable behavior based on S-R associations created
through environmental contingencies (rewards or punishments).
Stimulus
?
Response
B.F. Skinner
1904-1990
Nomotheism = assumption
of animal to human
commonality allowing
generalization of principles
of behavior
Instrumental (Operant) Conditioning
Stimulus - response in presence of reward
increase in response frequency
Stimulus - response in presence of punishment
decrease in response frequency
Guess who said…
Give me a dozen healthy infants, well-formed, and my own specified world to
bring them up in, and I’ll guarantee to take any one at random and train him
to become any type of specialist I might select—doctor, lawyer, artist,
merchant-chief, and yes, even beggar-man and thief, regardless of his
talents, penchants, tendencies, abilities, vocations, and race of his ancestors.
Watson
I think cognitive psychology is a hoax and a fraud, and that goes for brain
science too.
Skinner
Skinner confuses science with terminology. He apparently believes that if
he replaces commonplace `mentalistic' expressions with terminology drawn
from the laboratory study of behavior, but deprived of its precise content,
then he has achieved a scientific analysis of behavior. It would be hard to
think of a more striking failure to comprehend even the rudiments of
scientific thinking.
Chomsky
Cracks in the Behaviorism Armor
E. C. Tolman
1886-1959
Jean Piaget
1896 - 1980
In one of Tolman’s experiments rats
learned to run the route A to G to
obtain food. Then the learned path
is blocked. Generalization predicts
that pathways 9 & 10 would be
preferred, but it was 5 & 6. This led
Tolman to conclude that rats make
use of a “cognitive map”.
Piaget explained children’s thinking using descriptions of the
contents of the mind and processes such as accommodation and
assimilation. His observations, predictions, and explanations ran
counter to those of behaviorism.
The Paradigm Shift Arrives!!
1959, Review of Skinner’s book Verbal Behavior
1969, Aspects of a Theory of Syntax
Noam Chomsky
1928 - present
Ulrich Neisser
1928 - present
Presented arguments against Skinner’s claim that language could be
explained in terms of conditioning:
•People understand sentences that have never heard before and
produce sentences they have never said before.
•Children use expressions like “We goed to the store” even though they
have never heard the word “goed” nor been rewarded for using it.
•Showed how language could be best understood in terms of basic
elements and syntactic rules for combining those elements.
1967, Cognitive Psychology
Argued persuasively that the mind could be studied
experimentally and understood through models making use of
computer metaphors
1976, Cognition and Reality
Continued pursuing the computer metaphor but encouraged
cognitive psychologists to address behavior outside the laboratory.
If not introspection, then what?
Transcendental method (Kant, 1724-1804) =
Begin with observable facts and work backward
Using “Inference to best explanation”, cognitive psychologists ask,
“How could these observations have come about?”
Cognitive psychologists rely on the fact that mental processes,
themselves invisible, have visible consequence.
A Major Goal of Cognitive Psychology
To provide precise accounts of the internal processes
that are involved in the performance of cognitive tasks
Good cognitive psychology accomplishes this!
The Computer Metaphor
A computer, like a mind, has input, processing, and output. We should
be able to produce a description of the mind that includes these aspects.
What is a model?
A model is a hypothetical account of the structures and processes
involved in processing certain stimuli (e.g., faces) such that an
outcome (e.g., face recognition) is achieved. It is important to realize
that the processes are very often unconscious.
It is also important to recognize differences between a description at the
level of behavior and an explanation using a cognitive model. As we
proceed, we will contrast these two analyzes. The explanation using a
cognitive model will always refer to an underlying process associated
with a structure in the model.
In cognitive psychology, the structures and processes of a model are
assumed to be inherent to the human mind. However, there are
individual differences in how well particular processes function; these
differences may come about through genes, brain injury, or practice.
Examples of Cognitive Models
How do we build models? Four main ways….
1. Design research that allows inferences about internal processes
based on measurable responses or verbal protocols.
Often the measurable response is reaction time, errors, or
physiological responses such as GSR
Example: Study by Shepard & Metzler, 1971
Reaction Time Study
Same or Different?
Inference: People use an internal mental rotation process to respond
A Second Approach to Building Cognitive Models
2. Examine patterns of brain activity looking for patterns that
reflect hypothesized cognitive processes. Uses structural
neuroimaging techniques such at fMRI or PET scans.
e.g., semantic vs. episodic memory
A Third Approach to Building Cognitive Models
3. Use case studies with appropriate cognitive testing
e.g., Dr. S and AB
Both suffer from developmental prosopagnosia
meaning they have problems recognizing faces
Look for dissociations and double dissociation
Examples of double dissociations
digit span vs. spatial span
Williams Syndrome vs. prosopagnosia
Have you ever seen these faces before?
Do you know what their occupations are?
Do you know their names?
A Fourth Approach to Building Cognitive Models
4. Create computer programs of underlying processes
that produce behavior similar to human behavior
This approach is used by cognitive scientists in the area of
artificial intelligence
Important Concepts in Understanding Models
• Coding
• Channel capacity
• Information buffer
• Information store
• Parallel vs. serial
processing
• Modularity
• Neurological
specificity