semantic organization rosch and others have argued that our categorization of the world is not an...

Semantic organizationSemantic organization

• Rosch and others have argued that our categorization of the world is not an arbitrary historical accident, but reflects our psychological makeup, and hence is subject to investigation


– Berlin & Kay (1969) investigated colour names across 100 different languages

– order and frequency of colours used is consistent across cultures:black whitered green yellowbluebrownpurple pink orange grey


I.e. If there are two words for colours they tend to be black and white; three black, white, and red; etc.


– Rosch-Heider (1972) experiment with American-speaking subjects and members of the Dani, a stone-age New Guinea tribe

– Dani only had words for black and white


– Rosch built on a study by Brown & Lenneberg – Brown & Lenneberg showed that the Zuni,

whose language categorizes colours different from English-speakers, and North American English speakers tend to remember focal colours (e.g., pure green) better than nonfocal (e.g., purple)

– Focal colours are colours that are selected to be good exemplars of particular colours


– Experiment 1.showed a single coloured chip, and were required

to recognize it from a set of 160 chipsboth U.S. and Dani subjects performed better with

focal colours


– Experiment 2Dani required to associate different colours with

clan names; did better with focal colours than with non-focal colours

– Conclusionsame colours were focal for Dani as for US

subjectstherefore it is not language that makes certain

colours easier to remember, but their perceptual salience


• Why do people form categories? (Rosch,1978)– Cognitive economy; want to obtain as much

information from the environment as possible with the least effort

– the perceived world is a structured world; our perceptions shape the concepts that we form


• Structure of categories– categories have a horizontal and a vertical

dimensionhorizontal--segmentation of categories at the same

level of inclusiveness (e.g., sugar maple, silver maple)

vertical--different levels of inclusiveness


Superordinate Basic Subordinate

Furniture Chair Kitchen chair

Office chair

Lamp Floor lamp

Office lamp

Tree Maple Sugar maple

Silver maple


– Rosch argues that the basic level of organization is the most useful level for many purposes because it provides the most information for the least effort


– evidence to support hierarchical distinction– common attributes experiment

presented 9 taxonomies (e.g., tree, bird, fish, fruit, musical instruments, furniture, vehicle) at 3 levels

participants were instructed to list all of the attributes they could think of that were true of the items listed

few attributes at the superordinate level; significantly more at the basic and subordinate levels


– evidence to support hierarchical distinction– motor movements

subjects were presented same materials as in previous study, and were asked to describe motor movements

basic objects were the most general classes to have motor sequences in common

– similarity of shape and identifiability of averaged shape were other lines of evidence to support hierarchical distinction


• How should concepts be represented?

• Classical theory– what specifies a concept is some combination of

semantic features (e.g., bird -- has feathers, wings, lays eggs, has a beak, etc.)

– this model has been formally developed by Collins & Quillian, and Smith


• How should concepts be represented?• Classical theory

– problem is that many naturalistic concepts (birds, fruits, games, tools, etc.) are not rigidly defined

– not all birds fly, not all games involve more than one person, are competitive etc.

– Wittgenstein argued that family resemblance may be a more useful way to think about category membership


• How should concepts be represented?– The idea of family resemblance leads to the idea

that category membership is not determined by rigidly defined categories but by resemblance to a typical member

– Rosch asked subjects to rate basic level words as being typical or atypical of a category (e.g., robin, ostrich, chicken)


• How should concepts be represented?– results: subjects were very consistent in their

responses (i.e, robin rated as typical)– subsequent study showed that verification was

faster as well (robin is a bird is faster than chicken is a bird) for typical than for atypical categories

– Rosch showed that typical instances had many features in common with other members of the category


• Semantic relatedness is a general finding in this literature– prototypical members of a category are verified

quickly– related negative instances of a category are verified

more slowly (e.g., potato is a tree takes longer to verify than does rifle is a tree) Kintsch, 1980

– comparison process seems to be critical; not a simple category search


True-False latency as a function of relatedness

900

950

1000

1050

1100

1150

1200

1250

Related Unrelated

Mean RT (msec)

True

False


• Feature comparison models--Smith, Shoben, & Ripps (1974)– model assumes that concepts are represented by

bundles of features, separated into those that are defining, and those that are characteristice.g., bird -- defining -- feathers, lays eggscharacteristic -- flies, two legs, migrates


• Verify a sentence e.g., a robin is a bird– model postulates that subject retrieves features

associated with robin and with bird; if there is a high degree of overlap respond yes

– if there is less overlap begin a second slower stage in which the defining features are compared; if there is overlap respond yes; if there is a mismatch respond no


• Semantic network theories– Collins & Quillian – hierarchical memory structure model (see page

203 Radvansky)– critical assumptions: cognitive economy and a

hierarchical modelfeatures that are true of all animals such as eating

and breathing are stored at the highest level


• Semantic network theories– prediction: takes longer to respond to a true false

question the further away the two types of information are stored

Collins & Quillian 1969Collins & Quillian 1969

Type ofjudgement

Level 0 Level 1 Level 2

Property A canary cansing

A canary canfly

A canary hasskin

Category A canary is acanary

A canary is abird

A canary is ananimal

Collins & Quillian, 1969Collins & Quillian, 1969

Reaction time to verify property and category statements

900

1000

1100

1200

1300

1400

1500

Level 0 Level 1 Level 2

Mea

n R

T m

sec

Property

Categoryl

Collins & Quillian, 1969 Collins & Quillian, 1969

• Results were consistent with the hierarchical model with cognitive economy

• However, Conrad (1972) showed that if you control for relatedness, the level effect disappears

• also model has difficulty accounting for typicality effects of Rosch

More recent semantic networksMore recent semantic networks

• Spreading activation model of Collins and Loftus– see your text

More recent semantic representations


• Schemas, frames, and scripts– in 1932 Bartlett proposed that people remember new

material in terms of existing structures of knowledge that he dubbed schemas or schemata

– schemas represent some aspect of the environment, or our experience, or beliefs

– learning was conceptualized as an active process in which people attempted to make sense of what they had experienced

– effort after meaning



• Schemas, frames, and scripts– Bartlett studied effects of schemas on memory by

investigating memory for a North American folk tale (structured but unfamiliar material)

– showed that the students tended omit material that was strange to them or to distort it in ways that fit their expectations

– criticism--model too vague to be testable



• Schemas, frames, and scripts– with the advent of computers and the cognitive

approach to psychology scientists have begun to actively investigate these knowledge structures

– Minsky, Rumelhart, Schank, Abelson, Kintsch, Anderson



• Schemas, frames, and scripts– characteristics of this approach

this type of knowledge structure enables people to make sense of partially observed or described situations

e.g., the man bought a candy bar. People typically would infer that in money was given in exchange for the candy bar

e.g., the man drove in a nail




schemas have variables: buying something in a store; knowledge structure represents that it entails an exchange of money for a good; however, the amount of money or the good is left unspecified

hammering: there is a tool (hammer), an object or recipient of the action (nail), an action (hammering motion), and an agent or person




schemas can embed within each otherschemas operate at many levels of abstractionschemas represent knowledge or beliefschemas are active recognition devices



• Schemas, frames, and scriptsThorndyke (1977) studied the role of story

structure on recalloriginal version had a theme and then a narrative

that elaborated the themeversion 2: narrative then theme (after theme)version 3: narrative no themeversion 4: randomly ordered

Thorndyke 1977Thorndyke 1977

Recall as a function of organizational structure

0

20

40

60

80

100

1 2 3 4

Level in hierarchy

% R

ecal

l story

after-theme

no theme

random

Thorndyke (1977)Thorndyke (1977)

• Conclusions– level of recall depends upon

degree of structure provided in the storylevel of importance of the information (hierarchy

level)these two factors interact. Importance of

information is evident only in structured stories

Schank: scriptsSchank: scripts

• Schank and Abelson hypothesized that we have developed scripts that represent commonly experienced social events – e.g., going to a restaurant– e.g., going to a bank, taking a bus


• Restaurant scriptProps: restaurant, tables, menu, food, bill, money,

tipAgents: customer, waiter, cook, cashier, ownerEntry conditions: customer hungry, customer has

moneyResults: customer has less money, owner has

more money, customer is not hungry


• Restaurant script– Scene 1: entering

customer enters restaurantcustomer looks for tablecustomer decides where to sitcustomer goes to tablecustomer sits down

– Scene 2: ordering– Scene 3: eating– Scene 4: exiting

Neuropsychology of semantic memory


• Visual agnosia (Lissauer, 1888)– GL sustained a blow to the head– complained of difficulty seeing

examination showed normal visual acuitynormal ability to copy objectsrecognition of objects was severely impaired; but

it was not a general deficit; e.g., unable to recognize a whistle when presented visually, but able to recognize a whistle from its sound



• Tactile agnosia (Beauvais, 1978)– patient unable to recognize objects to touch, but

could recognize objects when they were presented visually

– also patient was able to use objects appropriately

• these results suggest that semantic memory is not a single unitary system, but has a number of subcomponents associated with the modality of input



– Warrington & Taylor (1978) showed that subjects with brain injury made two types of semantic errors in the visual modalityaccess disorder--some subjects had difficulty

recognizing a picture of an object (e.g., tennis racquet)

degraded semantic store--other subjects recognized the object, but had difficulty recognizing which object was commonly associated with the object (e.g., a tennis ball)



• Warrington & Shallice (1979) proposed the following criteria to distinguish access versus degraded semantic store impairments

consistency--if deficit is degraded semantic store, there should be consistency across test sessions (and type of test, Bayles)

On the other hand if the problem is one of access, then one might expect that different types of retrieval cues might lead to retrieval of the item

priming--patient should not show priming effects if there is a degraded store; however, certain primes might facilitate access to items if the problem is one of access



• Structure of semantic memory: modality specificity or a single semantic store?– one view holds that semantic memory consists of a

single amodal system– second view hypothesizes that there are separate

systems for verbal, visual, and other types of information

– the evidence at this point is not yet entirely clear on this point



• How are other types of information represented in semantic memory?– Some evidence suggests that evaluative

information is processed and stored in a different location than denotative information

Case Description of AMCase Description of AM

Successful businessman prior to TBI Average to very superior general intellectual

functioning Normal academic, attention, and executive

function abilities Generally intact memory abilities Poor social judgment; everything is positive

Park et al. (2001) Neuropsychologia

a b

c d

Amygdala

Temporal

Frontal

L. Amygdala

R. Temporal

Attitude Priming Study of AMAttitude Priming Study of AM

Purpose: to investigate AM’s evaluative rating of words

Hypothesis: impaired automatic evaluation of negative but not positive evaluative stimuli


Attitude Priming (continued)Attitude Priming (continued)

Method: attitude priming paradigm

– Participants: AM and 8 age - and education -matched controls

Procedure:– Phase 1: rate single words as “good” or “bad”– hypothesized positivity bias


Rating of Words in Phase 1Rating of Words in Phase 1

0

10

20

30

40

50

60

70

80

Controls AM

Nu

mb

er R

ated

"G

oo

d"

Controls

AM

Response Latency to Phase 1 Words

Response Latency to Phase 1 Words

0

500

1000

1500

2000

2500

3000

AM Control

Mse

c Negative

Positive

Phase 2Phase 2

Task: rate target as good or bad as quickly as possible

prime(pos or neg)

250 ms

blankscreen50 ms

target(pos or neg)

Control Priming Results Phase 2Control Priming Results Phase 2

640

680

720

760

800

Positive Target Negative Target

Mse

c Pos. Prime

Neg. Prime

AM Priming Results Phase 2AM Priming Results Phase 2

0

500

1000

1500

2000

2500

3000

3500

4000

Positive Target Negative Target

Mse

c Pos. Prime

Neg. Prime

Summary of Attitude PrimingSummary of Attitude Priming

Positivity bias in rating single words

Slowed responses only to words rated as bad

Priming in positive valence condition only Conclusion: AM can automatically access

positive but not negative evaluative information


Connotation Generation Study of AMConnotation Generation Study of AM

Purpose: to determine whether AM could access negative evaluative information when directed

Task: describe two positive and two negative features of single words (e.g., coffee)

Same 92 words used as primes in Experiment 1


Acceptable Good and Bad Connotations

Acceptable Good and Bad Connotations

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

AM Control

Acc

epta

ble

Co

nn

ota

tio

ns

Good

Bad

Semantic priming and AMSemantic priming and AM

• Purpose of experiment– to determine whether AM would show normal

semantic priming– prior research has shown that the latency to

respond to a target is facilitated when the prime preceding the target is semantically related compared to when it is unrelated

• Method– similar to Phase 2 of the first study


• Method– similar to Phase 2 of the first study– task: show prime-then target; make a lexical

decision about target item (word/nonword)


Mean response latency (ms) to semantically related and unrelated word pairs

300400500600700800900

1000

AM Control

Mea

n r

esp

on

se l

aten

cy

(ms) Related

Unrelated

ConclusionsConclusions

• Conclusions– AM impaired in his automatic processing of

negative evaluative informationpositivity biasno priming for negative evaluative words

– AM not impaired in his denotative or semantic processing of words

– suggests a dissociation between these two aspects of semantic memory

semantic organization rosch and others have argued that our categorization of the world is not an...

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colours different

different colours

purple focal colours

frequency of colours

certain colours easier

dani subjects

different languagesorder

level of inclusiveness