Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Chapter 8:
Representation and
Organization of
Knowledge in Memory:
Concepts, Categories,
Networks and Schemas
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Using Our Minds
• Knowing that…
– Declarative knowledge
• Knowing how…
– Procedural knowledge
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Declarative Knowledge
• Stored in Concepts
– A mental representation of an item and
associated knowledge and beliefs (cat,
tools, furniture)
long
tail
meows
Cat
furry
calico
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
When Do We Use Concepts?
• Create categories
• Make inferences
• Combine to form complex thoughts
• For communication
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Organizing Structures of Declarative
Knowledge
• Concept
– Unit of symbolic knowledge
• Category
– Rule used to organize concepts
• Schemas
– Framework used to organize concepts
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Different Types of Concepts
• Natural Concept
– Occur naturally (e.g. plants, trees, cats)
• Artifact Concept
– Created by humans (e.g., hammers, computers)
• Ad Hoc Concepts
– Created individually to suit a need (things you
need to be happy, things you do to please
parents)
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Different Theories on Concept
Organization
• Defining Features (Classical View)
• Prototypes
• Exemplars
• Hierarchically semantic networks
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Defining Features
• A defining feature
– Must have this to be
considered a
member
– What are the
defining features of
a mime?
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Problem with Defining Features Theory
• Difficult to specify necessary features
of some concepts
– What is the defining feature of a
monster?
– A widow?
– A family?
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Additional Defining Features Problem
• Typicality Effects
– Some things are better
examples of a concept than
others
– Robin is a more typical bird
than a ostrich
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Prototype Theory
• Abstracted representation of a category containing
•
salient features that are true of most instances
Characteristic features which describe what
members of that concept are like
– Monster prototype has these characteristics: Scary,
pale, has sharp teeth, is evil, lives in odd place (coffins,
closets, or graveyards)
– Vampires, Zombies, and Bogeymen all fit that
prototype well,
– Can a green, grumpy, lives in a garbage can monster
also fit? Yes, but less well.
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Prototype Theory
• Deals well with fuzzy concepts
• Fuzzy concepts are categories that
cannot be easily defined (Monster,
Games)
• To categorize, simply compare to
prototype
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Exemplar View
• No single prototype but rather multiple
•
•
•
examples convey idea what the concept
represents
Vegetable Concept = Peas, Carrots, or
Beans
Is a green pepper a vegetable?
The more similar a specific exemplar is to a
known category member, the faster it will
be categorized
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Exemplar View
• Similar to Prototype View
– Representation is not a definition
• Different: Representation is not
abstract
– Descriptions of specific examples
• To categorize, compare to stored
examples
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Synthesis: Combine Prototype &
Defining Feature
• Evidence for both, so combine
• Introduce the idea of the “core”
– Defining features that item must have
• Prototype
– Characteristics typical of examples
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Understanding of Defining Features
• Keil & Batterman (1984)
– 5-10 year olds exposed to category
– Smelly mean old man with a gun that took TV
because parents told him he could have it
– Friendly and cheerful woman who took toilet
without permission and no intention to return it
• Which is a robber?
– Not until close to age 10, did children see the
cheerful woman as a robber
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Theory Based View
• Knowledge of the world informs and
shapes our predictions about concepts
• Features in a complex network of
explanatory links indicate
– Relative importance of features
– Relations among features
• Objects classified into concept that
best explains the pattern of attributes
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Rips (1989)
• Sorp/Doon Story
– Manipulated if the change was caused by
an accident, a change in nature, or a
control group reading about sorps
• Participants were then asked
– Is it more similar to a bird or an insect?
– Is it more likely to be a bird or an insect?
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
More Support for Theory Based View
• Gelmen (2004)
– “Dog” and “Gold” categories
– Give a third item and ask child to draw an
inference based on perceptual similarity or
category membership
– Children often used category membership,
not just color or superficial features of
item
– Thus, the abstract essential meaning of
items was used by children
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Semantic Network Model
• Nodes represent concepts in memory
• Relations represented links among sets
of nodes
Robin
Property
Wings
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Collins & Quillian’s Model (1969)
• Structure is hierarchical
• Time to retrieve information based on
•
number of links
Cognitive economy
– Properties stored only at highest possible level
• Inheritance
– Lower-level items also share properties of
higher level items
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Collins & Quillian’s Model (1969)
Animal
Has skin
Breathes
Eats
Has fur
Has fins
Fish
Salmon
swim
Has gills
Dog
barks
4 legs
Is pink
Has spots
Dalmatian
Is edible
Lays eggs upstream
Skinny tail
Black &
white
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Support for Collins & Quillian Model
• Sentence verification task
• Indicate if the following sentences are true or
false: Measure reaction time
–
–
–
–
Salmon are pink.
Animals breathe.
A dog has four legs.
A dalmatian has skin.
• The more links traveled according to model, the
longer the reaction time of truth verification
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Collins & Loftus (1975) Semantic Model
• Got rid of hierarchy
• Got rid of cognitive economy
• Allowed links to vary in length to account
•
for typicality effects
Spreading activation
– Activation is the arousal level of a node
– Spreads down links
– Used to extract information from network
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
swims
fish
4 legs
Goldie
fur
dog
pet
Lucy
mutt
poodle
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Basic Level
Furniture, Animal
Superordinate
•Largest number of
features
•Used most often
Chair, Bird
Basic Level
Bean Bag, Robin
Subordinate
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Evidence Basic-Level is Special
• People almost exclusively use basic-level
names in free-naming tasks
• Children learn basic-level concepts sooner
than other levels
• Basic-level is much more common in adult
•
discourse than names for superordinate
categories
Different cultures tend to use the same
basic-level categories, at least for living
things
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Schemas
• Schemas are models of the external
world based on past experience
• Schemas for concepts underlying
situations, events, or sequences of
actions
• Abstraction that allows particular
objects or events to be assigned to
general categories
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Schemas
• Organize our knowledge
• May include other schemas
• Help in encoding, storage, and recall
• Allows us to make inferences
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Schema Research
• Tuckey & Brewer (2003)
– Examined the impact of schemas on
eyewitness memory
– One factor manipulated was the
ambiguity or schema consistency of film
crime watched
– Created a film that activated bank
robbery schema
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Tuckey & Brewer (2003)
Participants saw one of two short films
of a bank robbery
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Tuckey & Brewer (2003)
•Ambiguous schema film
–
–
–
–
–
–
Enter bank
“Hurry up”
Possible guns
Take money
Leave bank
Running escape
•Schema inconsistent film
– Partner chubby
– One wore a suit
– Another wore bright
clothing
– Was apologetic
– One escaped on bus
– One a female
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Tuckey & Brewer (2003)
• Ambiguity/Schema manipulation
• Half of the participants saw a film that contained
ambiguous scenes like
– Criminals may have guns
– Verbal demands of the tellers were made (but no explicit
demands for money)
• Other half of participants viewed a film that did not
have ambiguous scenes
– The bag the robber was holding was limp and could not have
hidden a gun
– Apologetic speech occurred in the film
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Tuckey & Brewer (2003)
Ambiguous
Schema
Schema
Inconsistent
Correct
information
1.5
2.84
Intrusions
2.3
1.11
•
Results indicated lower recall and more schema
consistent intrusions occurring in the
ambiguous condition
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Bower, Black, & Turner (1979)
• Participants read 18 stories
• 1, 2, or 3 stories read about each
schema
– 1 story about going to the doctor
– 1 story about going to the dentist
– Health care schema activated for both
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Bower, Black, & Turner (1979)
• Participants then asked if 3 particular
types of events happened in the stories
– Events actually in stories
– Events consistent with schemas, but not
actually in stories
– Novel, unrelated events
• Participants also rated their level of
confidence about each of their answers
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Bower, Black, & Turner (1979) Results
• Participants were confident
– About the actual events that they did read
– About schema-consistent events not actually in
story
• The more stories read about a certain schema,
•
the more confidence that the schema-consistent
event was in a story
Implications of the results
– Ideas contained in the schema become a part of the
memory with items and events actually experienced
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Brewer and Treyens (1981)
• Memory for graduate student's office
–
–
–
–
–
88 objects mentioned in recall
19 were inferred (not present)
9 people recalled books
8 people recalled skull
1 person recalled umbrella
• Participants recalled expected objects or
highly unexpected objects
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Scripts
• Type of schema about events
• Structure captures general information
about routine events
– Eating in a restaurant, attending a movie, a
visiting a doctor’s office
• Scripts have typical roles
– (Customers, waiter, cook), (ticket vendor,
patrons, refreshments), (doctor, nurse, patient)
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Scripts
• When we hear or read about a scripted
event, our knowledge of the entire
script is activated
• We can fill in or infer the scenes and
actions that are not explicitly
mentioned
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Schank and Abelman (1977)
• Visit a restaurant script
–
–
–
–
–
–
Sit down
Look at menu
Order food
Eat
Pay
Leave
• 73% of subjects produce the above actions
48% agreed on a further 9 actions
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Representing Procedural Knowledge
• Serial Processing
– Linear sequence of operations
– Create using production rules
• If – then rules
– If sliding on ice then pump the brakes
• Tasks may take multiple rules
– Organized into routines and subroutines
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
ACT-R Model
• Theory for simulating and understanding
•
•
•
human cognition
Goal is to create model that can simulate
how knowledge is organized and used to
produce behavior
J. Anderson is a prominent researcher in
this area
ACT-R Home Page: http://act.psy.cmu.edu
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
ACT-R Model
• Combines declarative and procedural
knowledge in a model
• Declarative knowledge is represented in
structures called chunks defined by its type
and slots
– Type represents concepts or categories (e.g.,
dogs) and slots as category attributes (e.g.,
color or size)
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
ACT-R Chunk Diagram
• The dog chased the cat
• Chunk diagram for this proposition
– Isa = chase
– Agent = dog
– Object = cat
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
ACT-R Production Diagram
• Procedural knowledge is represented in
productions
– IF the goal is to classify a person
– And he is unmarried
– THEN classify him as a bachelor
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Activation & ACT-R
• Spreading Activation
– Activation spreads via links across chunks
• Measures of Prior Learning
– The recency and frequency of practice of the
chunk as described in the previous unit
affects speed of activation
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Activation & ACT-R
• Sources of Activation
– The number of links connecting elements
of the chunks
• Weighting
– How much activation from source
• Strengths of Association
– The strength of association from source
to chunk
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
ACT-R Has Simulated…
• Myriad of successful models for a variety
of phenomena
– Visual search tasks
– Driving behavior
– RT to do paper, rock, scissors game under
differing circumstances
– Tower of Hanoi problem
– Category learning
– List memory
– Group decision making
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Acquisition of Procedural Knowledge
• Anderson (1980)
– Cognitive Stage
• Consciously think about steps to complete
task
– Associative Stage
• Practice the procedure
– Autonomous Stage
• Skill has become automatic
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Squire’s Non-declarative Knowledge
• Procedural knowledge
• Associative conditioning
– Classical and operant conditioning
• Simple nonassociative knowledge
– Habituation
– Sensitization
• Priming
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Squire’s Non-declarative Knowledge
Non-declarative (Implicit)
Procedural
(Skills &
Habits)
Priming
Simple
Emotional
Responses
Striatum
Neocortex Amygdala
Nonassociative
Skeletal
Musculature
Cerebellum Reflexes
Pathways
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Support for Squire’s Taxonomy
• Basil Ganglia damage
• Examine Parkinson’s and early Huntington
disease patients
• No apparent amnesia (declarative memory
intact)
• Problems with procedural memory
– Perceptual motor learning
– Habits & skills
• Just one example of variety of studies with
humans and animals have supported Squire’s
taxonomy
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Two Types of Priming
• Semantic priming
– Meaning is primed
– Remember Nurse-Doctor study?
• Repetition priming
– Prior exposure primes same items seen
later
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
Connectionist Model
• Parallel processing
– Multiple operations occur simultaneously
• Parallel Distributed Processing (PDP)
models
– Goal is to model information as it is
represented in the brain
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 8
The PDP Model
• The representation of information is
distributed
• Knowledge for specific things are not
stored explicitly, but stored in the
activations of patterns among units
• Learning occurs with changes in
connection strength by experience
• Units send excitatory and inhibitory
signals to other unit
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Cognitive Psychology, Fifth Edition, Robert J. Sternberg Chapter 8