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Semantic 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. Semantic organization. - PowerPoint PPT Presentation
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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
Semantic organizationSemantic organization
– 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
Semantic organizationSemantic organization
I.e. If there are two words for colours they tend to be black and white; three black, white, and red; etc.
Semantic organizationSemantic organization
– 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
Semantic organizationSemantic organization
– Rosch built on a study by Brown & Lenneberg showing 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
Semantic organizationSemantic organization
– 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
Semantic organizationSemantic organization
– 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
Semantic organizationSemantic organization
• 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
Semantic organizationSemantic organization
• 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
Semantic organizationSemantic organization
Superordinate Basic Subordinate
Furniture Chair Kitchen chair
Office chair
Lamp Floor lamp
Office lamp
Tree Maple Sugar maple
Silver maple
Semantic organizationSemantic organization
– 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
Semantic organizationSemantic organization
– 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
Semantic organizationSemantic organization
– 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
Semantic organizationSemantic organization
• 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
Semantic organizationSemantic organization
• 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
Semantic organizationSemantic organization
• 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)
Semantic organizationSemantic organization
• 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 organizationSemantic organization
• 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
Semantic organizationSemantic organization
True-False latency as a function of relatedness
900
950
1000
1050
1100
1150
1200
1250
Related Unrelated
Mean RT (msec)
True
False
Semantic organizationSemantic organization
• 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
Semantic organizationSemantic organization
• 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 organizationSemantic organization
• Semantic network theories– Collins & Quillian – hierarchical memory structure model (see page
261 Reed)– 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 organizationSemantic organization
• 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
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
More recent semantic representations
More recent semantic representations
• 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
More recent semantic representations
More recent semantic representations
• 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
More recent semantic representations
More recent semantic representations
• 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
More recent semantic representations
More recent semantic representations
• Schemas, frames, and scripts– characteristics of this approach
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
More recent semantic representations
More recent semantic representations
• Schemas, frames, and scripts– characteristics of this approach
schemas can embed within each otherschemas operate at many levels of abstractionschemas represent knowledge of beliefschemas are active recognition devices
More recent semantic representations
More recent semantic representations
• 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
Schank: scriptsSchank: scripts
• 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
Schank: scriptsSchank: scripts
• 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
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
Neuropsychology of semantic memory
Neuropsychology of semantic memory
• 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
Neuropsychology of semantic memory
Neuropsychology of semantic memory
– 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)
Neuropsychology of semantic memory
Neuropsychology of semantic memory
• 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
Neuropsychology of semantic memory
Neuropsychology of semantic memory
• 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
Neuropsychology of semantic memory
Neuropsychology of semantic memory
• 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
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
Park et al. (2001) Neuropsychologia
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
Park et al. (2001) Neuropsychologia
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
Park et al. (2001) Neuropsychologia
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
Park et al. (2001) Neuropsychologia
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
Semantic priming and AMSemantic priming and AM
• Method– similar to Phase 2 of the first study– task: show prime-then target; make a lexical
decision about target item (word/nonword)
Semantic priming and AMSemantic priming and AM
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
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