Joel Cooper

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Chapter 8
Joel Cooper University of Utah
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Last Class

• Dual-code theory (visual, verbal)
• Visual representations
• Verbal descriptions and their affect on visual
  store
• Spatial relations
• Mental Manipulation of spatial objects

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Today

• Representation and Organization of Knowledge in
  Memory
• Concepts
• Categories
• Networks
• Schemas

fur
4 legs
swims
fish
dog
Goldie
pet
poodle
Lucy
mutt
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What Is a Concept?

• A mental representation of an item and associated
  knowledge and beliefs (cats, tools, furniture)
• What do concepts do for us?
• Cognitive Economy
• Inferences
• Combine to form complex thoughts
• Communication

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Overview

• Concept
• Unit of symbolic knowledge
• Category
• Rule used to organize concepts
• Schemas
• Framework used to organize concepts

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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)

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Different Theories on Concept Organization

• Defining Features (Classical View)
• Prototypes
• Exemplars
• Hierarchically semantic networks

Concept Theories
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Defining Features

• Examine the features of an item to determine
  whether it is a particular concept
• A defining feature
• Must have this to be considered a member
• What are the defining features of a widow?
• A student?

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Defining Features Problem

• Problem with theory?
• Difficult to specify necessary features
• What is the defining feature of a monster? A
  wedding? A family?
• Typicality Effects
• Some things are better examples of a concept than
  others
• Robin is a more typical bird than a penguin

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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
• What are some characteristics of your concept of
  a monster?
• Do all monsters fit those characteristics?

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Prototype Theory

• Deals well with fuzzy concepts
• Fuzzy concepts are categories that cannot be
  easily defined (Monster, Games)
• To categorize, simply compare to prototype
• Prototype not concrete

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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

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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

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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

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Core/Prototype synthesis

• What are the core characteristics of a college
  student?
• What are the prototypical characteristics of a
  college student?

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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

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Name these items
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Basic Level
Superordinate
Furniture, Animal

• Level of abstraction
• which the most category
• cuts are made
• Largest number of
• features
• Used most often

Basic Level
Chair, Bird
Subordinate
Bean Bag, Robin
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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

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Semantic Network Model

• Nodes represent concepts in memory
• Relations represented links among sets of nodes

Robin
Wings
Property
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Sentence Verification TaskAnswer with Yes or
No

• All robins are birds
• All fish can swim
• Some birds can swim
• A bat is a bird
• All birds can fly
• Some birds are fish
• An ostrich is a bird
• All birds are robins

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Collins Quillians Teachable Language
Comprehender
A salmon has skin vs. A Dalmatian has spots
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Collins Quillians Teachable Language
Comprehender

• Semantic memory is organized as a network of
  interrelated concepts
• Each concept is represented as a node
• Concepts are linked together by pathways
• Activation of one concept spreads to
  interconnected nodes
• Economy of representation

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Semantic Network Models
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Spreading Activation

• Activation is the process of retrieval
• Working memory is activated LTM
• When a concept becomes active, activation spreads
  to all other interconnected nodes
• Activation spreads to all related nodes
• How do you evaluate sentences like A robin is
  an animal?

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Collins Quillians TLC
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Spreading Activation

• Activation spreads from each of the concept nodes
  (Robin Animal)
• When two spreading activations meet, an
  intersection is formed
• Robins BIRD
• If no intersection, a quick no
• If intersection, decision stage operates to
  determine if sentence is valid

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Testing Spreading Activation

• It takes time for activation to spread
• Greater distances longer RT
• Verification time for items 0, 1, and 2 links

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Problems for TLC

• Typicality effects - how many links separate- A
  canary is a bird?- A robin is a bird?- A
  chicken is a bird?- An ostrich is a bird?
• RT varied -- the less typical birds took longer
  than the more typical birds

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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

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Modifications of Network Models
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Semantic Priming recap

• Concepts linked by spreading activation
• Prime ProbeDoctor NurseBread ButterDoctor B
  utterBread Nurse
• Sometimes the prime facilitates processing.

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Spreading Activation recap

• Spreading activation is thought to be automatic
• Governed by data-driven aspects of processing
• How do expectancies affect semantic access?
• Automatic vs Conscious Strategies (Atentional)
• Fast vs Slow
• Effortless vs Effortful
• Benefits vs Costs Benefits

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Neelys Experiment

• Aimed at contrasting
• Automatic Spreading Activation (ASA)
• Limited Capacity Attention (LCA)
• ASA Automatic, Fast, Effortless, Benefits
• LCA Attentional, Slow, Effortful,
• Benefits (if correct)
• Costs (if incorrect)

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Neely (Cont.)

• Stimuli (Birds, Body Parts, Buildings)
• Subjects told- If prime is bird, expect to see
  birds (80)- If prime is body, expect to see
  building (80)- If prime is building, expect to
  see body (80)
• ASA Semantic Relatedness
• LCA Expectancies

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Neely s Predictions
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Neely s Findings
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Accessing Semantic Memory

• Short SOAs Automatic activation (ASA)-
  Benefits, but no costs
• Long SOAs Expectancies (LCA)- Benefits -- if
  correct- Costs -- if incorrect

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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

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Schemas

• Organize our knowledge
• May include other schemas
• Help in encoding, storage, and recall
• Allows us to make inferences

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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

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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

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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

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Schema and Spreading activation
Have you ever had the same random thought as a
friend at exactly the same time? Have you ever
had a conversation with a friend that looped and
twisted and ended up in a seemingly random
place? One explanation for this is a similar,
shared schema
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Scripts

• Type of schema about events
• Structure captures general information about
  routine events
• Eating in a restaurant, attending a movie, a
  visiting a doctors office
• Scripts have typical roles
• (Customers, waiter, cook), (ticket vendor,
  patrons, refreshments), (doctor, nurse, patient)

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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

Scripts and Schema are memory!
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Schank and Abelman (1977)

• Visit a restaurant script
• Sit down
• Look at menu
• Order food
• Eat
• Pay
• Leave
• 73 of subjects produce the above actions48
  agreed on a further 9 actions