General KnowledgeGeneral Knowledge Structure of Semantic MemoryStructure of Semantic Memory

– BackgroundBackground

– Feature Comparison ModelFeature Comparison Model

– Prototype ApproachPrototype Approach

– Exemplar ApproachExemplar Approach

– Network ModelsNetwork Models

Schemas & ScriptsSchemas & Scripts– BackgroundBackground

– Recall of ScriptsRecall of Scripts

– Schemas & Memory SelectionSchemas & Memory Selection

– Schemas & Boundary ExtensionSchemas & Boundary Extension

– Schemas & Memory AbstractionSchemas & Memory Abstraction

– Schemas & Memory InferencesSchemas & Memory Inferences

– Schemas & Integration in MemorySchemas & Integration in Memory

– ConclusionsConclusions

Semantic MemorySemantic Memory General Conceptual KnowledgeGeneral Conceptual Knowledge

Lexical Knowledge (e.g., “apple” and )Lexical Knowledge (e.g., “apple” and )

Organized - (e.g., ‘pencil’ related to ‘pen’; think Organized - (e.g., ‘pencil’ related to ‘pen’; think

of ‘apple’ ----> ‘banana’of ‘apple’ ----> ‘banana’

Categories and ConceptsCategories and ConceptsCategoryCategory - a class of objects that belong together (e.g., - a class of objects that belong together (e.g.,

variety of objects: ‘fruits’ or ‘apple’)variety of objects: ‘fruits’ or ‘apple’)

ConceptConcept - mental representation of a category - mental representation of a category

Concepts allow us to make inferences when we Concepts allow us to make inferences when we encounter new instances (e.g. read ‘chair)encounter new instances (e.g. read ‘chair)

NaturalNatural concepts vs. concepts vs. ArtifactsArtifacts

QuestionsQuestions– Organization and Structure?Organization and Structure?– Storage?Storage?– Inferences?Inferences?– Cognitive Economy?Cognitive Economy?– Relatedness and Similarity?Relatedness and Similarity?

apple tabledog pentree chair

Feature Comparison ModelsFeature Comparison Models Concepts = list of features or attributes (e.g., Smith, Concepts = list of features or attributes (e.g., Smith,

Shoben, and Rips 1974)Shoben, and Rips 1974) DefiningDefining vs. vs. CharacteristicCharacteristic Features Features Decision Process - 2 StagesDecision Process - 2 Stages

– Stage 1Stage 1 = global comparison = global comparison

– Stage 2 = compare defining featuresStage 2 = compare defining features Research Research

– Typicality EffectTypicality Effect

– Category Size Effect (faster RTs for membership in Category Size Effect (faster RTs for membership in small category) NOT explainedsmall category) NOT explained

Other ProblemsOther Problems

The Sentence Verification TechniqueThe Sentence Verification Technique

For each of the items below, answer as For each of the items below, answer as quickly quickly as possibleas possible either true or false. either true or false.

1.1. A poodle is a dog.A poodle is a dog.2.2. A squirrel is an animal.A squirrel is an animal.3.3. A flower is a rock.A flower is a rock.4.4. A carrot is a vegetable.A carrot is a vegetable.5.5. A mango is a fruit.A mango is a fruit.6.6. A petunia is a tree.A petunia is a tree.7.7. A robin is a bird.A robin is a bird.8.8. A rutabaga is a vegetable.A rutabaga is a vegetable.

Prototype ApproachPrototype Approach

Classical View vs. ProtoypeClassical View vs. Protoype

RoschRosch

Idealized version of category (example)Idealized version of category (example)

Graded membership - not all memebersGraded membership - not all memebers

Bachelor = Unmarried, maleBachelor = Unmarried, male

But which of the following are really bachelors?But which of the following are really bachelors?

1.1. My 32-year old cousin, John, who works at a My 32-year old cousin, John, who works at a

bank in Chicagobank in Chicago

2.2. My 6 month old son TimMy 6 month old son Tim

3.3. An elderly Catholic PriestAn elderly Catholic Priest

Characteristics of PrototypesCharacteristics of Prototypes

1.1. Prototypes are supplied as examples of a category.Prototypes are supplied as examples of a category.

2.2. Prototypes serve as reference points.Prototypes serve as reference points.

3.3. Prototypes are judged more quickly after priming.Prototypes are judged more quickly after priming.

4.4. Prototypes can substitute for a category name in a Prototypes can substitute for a category name in a sentence.sentence.

5.5. Prototypes share common attributes in a family Prototypes share common attributes in a family

resemblance categoryresemblance category..• No one attribute shared by all membersNo one attribute shared by all members

• In / out phenomenonIn / out phenomenon

Mervis, Catlin, & Rosch (1976)Mervis, Catlin, & Rosch (1976)

Group 1Group 1: generated examples for 8 different categories: generated examples for 8 different categories– Birds? … robin, sparrow …Birds? … robin, sparrow …– Fruits?Fruits?– Sports?Sports?

– EtcEtc.. Group 2Group 2: provided prototype : provided prototype ratingsratings (low to high) for each (low to high) for each

exampleexamplee.g.,e.g., sparrow 7 - highsparrow 7 - high

penguin 2 - lowpenguin 2 - low

Strong correlation between frequency and ratingStrong correlation between frequency and rating Typicality EffectTypicality Effect

Lexical Decision TaskLexical Decision Task

apple

table

tadjld

mountain

pudor

The following items: Decide whether each item is a word (‘yes’) or not a word (‘no’). Respond by pressing the ‘yes’ button or the ‘no’ button:

What Is a What Is a PrimingPriming Effect? Effect?

doctor

Y/N

450 ms

Lexical Decision Task

doctor

Y/N

400 ms

hospital

doctor

Y/N

450 ms

automobile

Robin Penguin

Robin480 ms.

Penguin660 ms.

Bird Bird

550 ms. 670 ms.

Group 1:Group 1: Prototype Ratings Prototype Ratingse.g., vehicles: car, truck, tractor, slede.g., vehicles: car, truck, tractor, sled

vegetable: carrots, beets, eggplantvegetable: carrots, beets, eggplant

clothing: shirt, sweater, vestclothing: shirt, sweater, vest

Group 2:Group 2: List attributes possessed by each List attributes possessed by each item: item:

e.g., car: wheels, steering wheel, doors, e.g., car: wheels, steering wheel, doors, etc. etc.

Score:Score: What proportion of an item’s attributes were What proportion of an item’s attributes were shared by other category member’sshared by other category member’s

Strong correlation between score and prototype Strong correlation between score and prototype rating.rating.

Prototype Ratings for Words in Prototype Ratings for Words in Three CategoriesThree Categories

Levels of Categorization 1Levels of Categorization 1

Superordinate LevelSuperordinate Level

– furniture, animals, toolsfurniture, animals, tools

Basic LevelBasic Level

– chair, cat, screwdriverchair, cat, screwdriver

Subordinate LevelSubordinate Level

– desk chair, persian cat, phillips screwdriverdesk chair, persian cat, phillips screwdriver

Levels of Categorization 2Levels of Categorization 2

Superordinate levelSuperordinate levelBasic-levelBasic-levelSubordinate levelSubordinate level

1.1. Basic-level names are used to identify objectsBasic-level names are used to identify objects

2.2. Members of basic-level categories have more Members of basic-level categories have more

attributes in commonattributes in common

3.3. Basic-level names produce the priming effectBasic-level names produce the priming effect

4.4. Experts use subordinate categories differentlyExperts use subordinate categories differently

Carrot Vegetable

Same / Different Same / Different

Priming Effect No Priming Effect

Expert Novice

Superordinate

Basic 10 + 11 +

Subordinate 10 + 6 +

Exemplar ApproachExemplar Approach Store specific Store specific instancesinstances or examples ( or examples (exemplars)exemplars) Decision process = comparison of new item to stored Decision process = comparison of new item to stored exemplars.exemplars. Comparison to prototype approach = Comparison to prototype approach =

Stored Representation

Prototype Approach Exemplar

Typical or idealizedrepresentation

Stored representation = Specific members / instances

•Absence of features -- (characteristic vs. defining)

Picture of DogPicture of Dog

Exemplar ApproachExemplar Approach

No abstraction - no summary representation.No abstraction - no summary representation.

Storage requirements.Storage requirements.

May be more suitable for smaller categories.May be more suitable for smaller categories.

Evidence from Social Psychology - stereotypesEvidence from Social Psychology - stereotypes

Individual differencesIndividual differences

Co-existence: prototypes and exemplarsCo-existence: prototypes and exemplars

Strategic differencesStrategic differences

Explaining Explaining concept learningconcept learning! !

Network ModelsNetwork Models Semantic networksSemantic networks

– (concepts and connections ----> nodes and (concepts and connections ----> nodes and links)links)

Collins & LoftusCollins & Loftus– Node = conceptNode = concept

Link = relation or connectionLink = relation or connection– Spreading activationSpreading activation

Sentence verification ----> intersectionsSentence verification ----> intersections Explaining ‘Typicality Effect’Explaining ‘Typicality Effect’ Anderson’s ACT* TheoryAnderson’s ACT* Theory

Activation SpreadActivation Spread

Does a robin breathe?

AndersonAnderson

ACT = Adaptive Control of ThoughtACT = Adaptive Control of Thought

Declarative vs. Procedural KnowledgeDeclarative vs. Procedural Knowledge

Propositional NetworksPropositional Networks

PropositionProposition - the smallest unit of knowledge with - the smallest unit of knowledge with

a truth valuea truth value

Proposition = node + linkProposition = node + link

Working Memory - active part of Long Term Working Memory - active part of Long Term

MemoryMemory

Susan gave a white cat to Maria, who is the president of the club.

1. Susan gave a cat to Maria.

2. The cat was white.

3. Maria is the president of the club.

Susan gave a white cat to…Susan gave a white cat to…

SchemasSchemas

1.1. Larger cognitive unitsLarger cognitive units

2.2. Packages of interrelated unitsPackages of interrelated units

3.3. Used to interpret, encode, understand, and Used to interpret, encode, understand, and remember new instancesremember new instances

4.4. Provide Provide expectationsexpectations about what should occur about what should occur (top - down)(top - down)

5.5. Default values / parts - filled in when schema Default values / parts - filled in when schema activatedactivated

6.6. Sometimes - errorsSometimes - errors

““When Lisa was on her way back from When Lisa was on her way back from the store with the balloon, she fell and the store with the balloon, she fell and the balloon floated away.”the balloon floated away.”

ScriptsScripts

Simple, well- structured sequence of events Simple, well- structured sequence of events associated with a highly familiar activityassociated with a highly familiar activity

Schema vs. scriptSchema vs. script Recall of scriptsRecall of scripts

– Different from conceptual categories (Barsalow Different from conceptual categories (Barsalow & Sewell, 1985)& Sewell, 1985)

– Script Identification - early vs. late (Trafimow Script Identification - early vs. late (Trafimow and Wyer, 1993)and Wyer, 1993)

Appreciating the similarity of scriptsAppreciating the similarity of scripts

Trafimow & Wyer (1993)Trafimow & Wyer (1993) 4 different scripts4 different scripts

– Photocopying a piece of paper Photocopying a piece of paper

– Cashing a checkCashing a check

– Making teaMaking tea

– Taking the subwayTaking the subway

Irrelevant details added (e.g., taking candy out of pocket)Irrelevant details added (e.g., taking candy out of pocket) Script - identification information presented first or lastScript - identification information presented first or last FillerFiller Recall: of script - related eventsRecall: of script - related events

23%23% vs.vs. 10%10%

(script identified first)(script identified first) (script identified last)(script identified last)

Schemas and Memory SelectionSchemas and Memory Selection

Remember best info Remember best info consistentconsistent with schema with schema

or or inconsistentinconsistent

Brewer & Treyons (1981)Brewer & Treyons (1981)

Rojahn & Pettigrew (1992)Rojahn & Pettigrew (1992)

Incidental vs. Intentional learningIncidental vs. Intentional learning

Schemas and Boundary ExtensionSchemas and Boundary Extension

Schemas and Memory AbstractionSchemas and Memory Abstraction

Abstraction Abstraction Verbatim vs. GistVerbatim vs. Gist Constructive ApproachConstructive Approach

– Bransford & Franks (1971)Bransford & Franks (1971)– Holmes & Colleagues (1998)Holmes & Colleagues (1998)

Pragmatic ApproachPragmatic Approach– Murphy & Shapiro (1994)Murphy & Shapiro (1994)– Attention Allocation / ControlAttention Allocation / Control

C & P compatibleC & P compatible

Schemas and Inferences in MemorySchemas and Inferences in Memory

Bartlett (1932)Bartlett (1932)

Ebb vs. BartlettEbb vs. Bartlett

Interaction of prior knowledge and experience and Interaction of prior knowledge and experience and

formation of new memoriesformation of new memories

““War of the Ghosts” storyWar of the Ghosts” story

Initial vs. Delayed RecallInitial vs. Delayed Recall

Bransford, et al (1972)Bransford, et al (1972)

Implications - e.g., advertising Implications - e.g., advertising

Schemas and Integration in MemorySchemas and Integration in Memory

Final process in memory formationFinal process in memory formation

Result of Result of selection, abstraction,selection, abstraction, and and inferenceinference

Important!!Important!!

Integration and Delayed RecallIntegration and Delayed Recall

Integration and Limited Memory CapacityIntegration and Limited Memory Capacity