Transcript Chapter 2 : Cognitive Neuroscience

Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Chapter 7:
Representation and
Manipulation of
Knowledge in Memory:
Images and Propositions
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Cognitive Psychologists Study Mental
Representations
• Methods
– Self report
– Rationalist approach
– Empirical support
• Experiments
• Neuropsychological studies
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Mental Imagery
• Internal representation of items that are
not currently being sensed
– May be old, new, futuristic, imaginary
– May involve any of the sensory
modalities
• Imagine a taste, a sight, a touch
– Majority of research on Visual Imagery
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Mental Imagery
• Kosslyn proposes images are used to
help solve certain types of problems
– How many chairs are there in your
house?
– Do bunnies have whiskers?
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Dual Code Theory
• Paivio (1971)
• We use two codes to represent
information
– Image codes- analogue codes, shares
some perceptual features
– Symbolic codes- arbitrary symbols to
represent items (e.g., words)
– Two codes are linked
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Evidence for Dual Code Theory
• Paivio compared concrete words
(potato, horse) with abstract words
(justice, love)
• Found participants were better able to
recall concrete words
• Concluded that dual code was created
for concrete words (analog & verbal
label) but not for abstract words
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Visual Codes are Processed
Differently than Symbolic Codes
– Visual information interferes with spatial
information
– Verbal labels interfere with spoken words
– Sequence matters more for words, not so
much for unrelated images
– Thus, each type of code is affected by
different manipulations
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Evidence for Dual Code Theory
• Brooks (1968)
– One group saw a block
diagram of a letter
– Memorized it
– Were asked to mentally
travel the letter and
indicate if the corner was
on the extreme top or
bottom
Start
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Evidence for Dual Code Theory
• Brooks (1968) cont.
– Second group saw a
sentence
– Memorized it
– Were asked to classify
each word as a noun
by indicating "yes" or
"no"
– Verbal task
A bird in the hand is
not in the bush
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Evidence for Dual Code Theory
• Brooks (1968) cont.
• Participants were then
asked to respond in one
of two ways
– Say “Yes” or “No”
– Point to the answer “Yes
or No”
– Why was this important?
Yes
No
No
Yes
Yes No
Yes No
Yes
No
No Yes
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Evidence for Dual Code Theory
•Brooks (1968) Results
Task
Verbal
Pointing
Letter Diagrams
11.3 sec.
28.2 sec.
Sentences
13.8 sec.
9.8 sec.
For image task, RT was slower when pointing.
For the symbolic task, RT was slower for the verbal
response.
Different pattern = different processing for different codes
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Evidence for Dual Code Theory
• te Linde (1982)
• Participants answered questions about word or
picture pairs
Question
Word Stimuli
Associated?
Mouse-Cheese
Similar size?
Thimble-Acorn
Picture Stimuli
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
te Linde (1982) Results
2000
Milliseconds
1800
Words
Pictures
1600
1400
1200
1000
800
600
Association
Size
Decision
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Propositional Theory
• Do not store in form of images
• Instead have a “generic” code that is
called “propositional”
• Stores the meaning of the concept
• Create a verbal or visual code by
transforming the propositional code
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Propositional Representations
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Test Your Visual Imagery Ability!
• Form a mental image of this picture
• Which of the pictures on the next slide are
part of this picture?
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
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Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Try Again with Another Design
•Form a mental image of this picture
•Which of the pictures on the next slide are part of
this picture?
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
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Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Carmichael, Hogan, & Walters (1932)
• Participants were shown simple figures
with one of two verbal labels
Sun or ship’s wheel
Hourglass
Or
Table
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Carmichael, Hogan, & Walters
(1932) Results
Chapter 7
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Carmichael, Hogan, & Walters (1932)
Results
• Later participants were asked to draw
items seen
• Participants distorted the images to fit
the labels
• This pattern supports the idea that
images may be stored propositionally
not as original analog image
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Analogical Limitations
• Inability to see parts has led some to
support a propositional code rather
than an analogical code
• Demonstrates mental images are not
always precise
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Finke, Pinker & Farah (1989)
• Imagine a capital letter D. Rotate the figure
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90 degrees to the left. Now place a capital
letter J at the bottom
Imagine a capital letter N. Connect a
diagonal line from the top right corner to the
bottom left corner. Now rotate the figure 90
degrees to the right
Demonstrates that participants could
manipulate images
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Mental Imagery
•Shepard & Metzler
(1971)
•Subjects had to decide
whether displays had two
similar shapes
•Some pairs were similar,
but rotated to various
degrees
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Shepard & Metzler (1971) Results
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
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Mental Imagery Studies Demonstrate
Active process
Response times are proportional to
degree of rotation
People can rotate images in threedimensional space as easily as twodimensional space
Images are “Mental Sculptures”
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Functional-Equivalency Hypothesis
• First proposed by Shepard and Kosslyn
• Mental images are internal
representations that operate in a way
that is analogous to the functioning of
the perception of physical objects
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Neuropsychological Evidence & Mental
Imagery
• Cohen & Kosslyn
• Same brain areas are involved in
perception and mental rotation
• Support for functional-equivalence
hypothesis
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Functional-Equivalence Evidence
• Kosslyn (1975)
– Examine how participants scan and use images
– Some participants imagine an elephant next to a
rabbit
– Others imagine a rabbit next to a fly
– Then answer questions about the rabbit
• Does the rabbit have whiskers?
• Does the rabbit have ears?
• Does the rabbit have a beak?
– Reaction time to answer is measured
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Kosslyn (1976)
• Asked college students and fourth
graders simple questions about animals
– Does a cat have claws?
– Does a cat have a head?
• Varied the type of instructions used to
answer questions
– Imagery instructions
– No imagery
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Kosslyn (1976) Results
• In imagery condition, questions were
answered faster if the attribute was
larger
• In no imagery condition, questions
were answered faster based on
distinctiveness of characteristic for the
animal, no impact of size
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Size Judgments (Moyer, 1973)
• Which is larger, moose or roach?
• Which is larger, wolf or lion?
– When objects are similar in size, participants
imagine both objects and then compare the size of
the objects in their image
– Similar results when making comparisons of
actual physical objects
– The closer in size, the longer the reaction time
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Functional-Equivalence Evidence
•Kosslyn (1983)
•Memorize map
•Later ask to scan image
•Manipulate distance between items in scan
– Hut to grasses
– Lake to Hut
•Measure reaction time
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Kosslyn (1983) Results
• Linear relationship between the distance to scan
and actual reaction time of participants
• Further support for functional-equivalence
hypothesis
– Mental images are internal representations that
operate in a way that is analogous to the functioning
of the perception of physical objects
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Finke (1989) on Functional Equivalence
• We use similar transformation on objects and
mental images
• Spatial arrangements of a mental image are
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•
similar to spatial arrangements of actual
object
Images can be used to generate information
not explicitly stored during encoding
Processes of visual system are used on both
mental images and visual objects
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Demand Characteristics
• Major criticisms of Kosslyn’s Research
– Pylyshyn
– There is only one code, propositional
– The results due to task demands
– The instructions imply some necessary
relationship between the physical distance
and time required
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Demand Characteristics & Mental
Scanning
• Participants give the experimenters the
pattern they expect
– Intons-Peterson replicated research but
mislead experimenters
• If experimenter expectations are part of
demand characteristics, then leading them to
believe that longer distances would lead to
faster responding should alter the results
• Evidence was found to support demand
characteristics idea
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Demand Characteristics & Mental
Scanning
• Jolicoeur & Kosslyn (1985)
– Created a false demand characteristic for a U
shaped function for participants
– Proposed that Gestalt principle of proximity
makes close points “hard”, and distant points
would also take longer
– No experimental expectancy effect found
– Supports idea that image is being used
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Johnson-Laird (1983)
• Proposed there are three types of mental
representations
– Propositional representations which are pieces
of information resembling natural language
– Mental models which are structural analogies of
the world
– Mental imagery which are perceptual models
from a particular point of view
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Characteristics of a Mental Model
• A representation of a described situation
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•
rather than a representation of a text itself or
the propositions conveyed by a text
The structure corresponds to the functional
relations among entities as they would exist
in the world
A simulation of events in the world, either
real or imaginary
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Evidence for Mental Models
• Kerr (1983)
– Studied participants who were blind
– Created a tactile Kosslyn Map study equivalent
– Participants had to study the island, given a
physical map to touch
– Asked the same scanning questions
– Found the same pattern of results—longer
distances, longer reaction times
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Visual Imagery & Spatial Imagery
• Visual Imagery (images are visual)
– Seeing colors
– Comparing shapes
• Spatial Imagery (analog spatial format)
– Rotating objects
– Aiming and shooting at a target
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Neuroscience Evidence
• Farah (1988)
– Brain Injury Case Study (L.H.)
– Gave some visual tasks
• Color identification, object naming
– Gave some imagery tasks
• Mental rotation, mental scanning
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Farah (1988) Results
• L.H.
– Poor visual image skill
– Normal spatial image skill
• Thus, both types of imagery must exist
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
In Sum, Researchers Have Proposed
• Evidence for analog codes
• Evidence for propositional codes
• Evidence for mental models
• Evidence for a mental imagery that is
spatial
• Evidence for mental imagery that is visual
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Cognitive Maps: Historically
• Tolman – Rats
• von Frisch – Bees
• Thorndyke – Humans
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Creating Cognitive Maps
• Gain increased spatial knowledge
• Using three types of knowledge
– Landmark (special buildings)
– Route-road (procedures to get to one
place from another)
– Survey (global map-like view)
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Tversky (1993)
• Cognitive maps more like cognitive
collages
• Constructionist view of creating
cognitive maps
• Distortions can occur when using
heuristics
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Heuristics Affecting Cognitive Maps
• Rotation heuristic
– Tend to ‘regularize’ tilted landmarks in maps to
appropriate E-W or N-S axis
• Alignment heuristic
– Students view two maps of the Americas
– One a correct map, and a second map which
was altered (South America was moved
westward with respect to North America)
– A majority of students thought the altered map
was the correct one
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Heuristics Affecting Cognitive Maps
• Density Heuristic
– More landmarks between two points, the
greater the distance we estimate
• Right angle bias
– Streets are drawn at 90-degree angles (even
when they are not)
• Symmetry heuristic
– Irregular geographic boundaries are made
regular (e.g., Americans straighten out the
Canadian border)
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 7
Creating Maps from Text
• Tversky
– What impact does the perspective of
participant versus observer play in
creation of a code
• As a participant, emphasize propositional
code
• As an observer, emphasize perceptual code
– Findings indicate both play a role