Classical Categories Classical Categories versus Experientially versus Experientially

Based CategoriesBased CategoriesPrototypes and the Prototypes and the

Basic LevelBasic LevelLinguistics 5430Linguistics 5430

Spring 2007Spring 2007

The Mysteries of The Mysteries of CategorizationCategorization

Using common nouns for things requires us to Using common nouns for things requires us to categorize.categorize.

But what does it mean to know the name of But what does it mean to know the name of something—knowing a something—knowing a descriptiondescription, a , a contextcontext, an , an imageimage??

How do we use names appropriately?How do we use names appropriately? How do our purposes affect the way we How do our purposes affect the way we

categorize?categorize? How do we learn names (How do we learn names (Plato’s problemPlato’s problem)? )? Are linguistic and nonlinguistic categories the Are linguistic and nonlinguistic categories the

same (Jackendoff’s problem)?same (Jackendoff’s problem)?

Answers from PhilosophyAnswers from Philosophy

Putnam (1975: 227) on Putnam (1975: 227) on semantic externalismsemantic externalism: : “’Meanings’ just ain’t in the head’. “’Meanings’ just ain’t in the head’.

This view follows from Kripke’s (1980) This view follows from Kripke’s (1980) causal causal theorytheory of names: a name’s reference is fixed of names: a name’s reference is fixed by an original act of dubbing, after which the by an original act of dubbing, after which the name becomes a rigid designator of that object.name becomes a rigid designator of that object.

Later uses of the name succeed in referring to Later uses of the name succeed in referring to the referent by being linked to that original act the referent by being linked to that original act via a causal chain.via a causal chain.

This view is opposed to Russell’s This view is opposed to Russell’s descriptive descriptive theorytheory of names: proper names are of names: proper names are abbreviated definite descriptions.abbreviated definite descriptions.

Answers from PhilosophyAnswers from Philosophy

The descriptive theory was devised to account The descriptive theory was devised to account for the coherence of sentences like for the coherence of sentences like Santa Santa Claus does not existClaus does not exist..

But Kripke argues that to use a name But Kripke argues that to use a name appropriately, you need only be part of a long appropriately, you need only be part of a long historical chain reaching back to the original historical chain reaching back to the original naming event.naming event.

Further, we can make counterfactual Further, we can make counterfactual statements about the referents of proper statements about the referents of proper names.names.

Putnam extends the causal theory to natural Putnam extends the causal theory to natural kind terms.kind terms.

The Division of Linguistic The Division of Linguistic LaborLabor

Putnam says: for me, both Putnam says: for me, both elmselms and and beechesbeeches are ‘deciduous trees growing in North America’. are ‘deciduous trees growing in North America’.

Yet if Putnam claims, ‘The elm is the most Yet if Putnam claims, ‘The elm is the most popular ornamental tree in North America’ this popular ornamental tree in North America’ this statement can be evaluated as true or false.statement can be evaluated as true or false.

Nothing in Putnam’s head fixes his elm Nothing in Putnam’s head fixes his elm reference; rather, the linguistic community reference; rather, the linguistic community contains people who contains people who dodo know the difference know the difference between the two trees. between the two trees.

The experts ensure that when he says The experts ensure that when he says elmelm he he is talking about elms. This is 'the division of is talking about elms. This is 'the division of linguistic labor'.linguistic labor'.

Answers from Machine Answers from Machine LearningLearning

Merely using the right word in the right place is in itself an Merely using the right word in the right place is in itself an adaptive ability. A child can usefully learn that the place she adaptive ability. A child can usefully learn that the place she lives is Colorado, […] a college student that operant conditioning lives is Colorado, […] a college student that operant conditioning is related to learning, a businessperson that TQM is the rage, is related to learning, a businessperson that TQM is the rage, before needing any clear idea of what these terms stand for. before needing any clear idea of what these terms stand for. Many well read adults know that Buddha sat long under a Many well read adults know that Buddha sat long under a Banyan Tree (whatever that is) and Tahitian natives lived Banyan Tree (whatever that is) and Tahitian natives lived idyllically (whatever that means) on breadfruit and poi (whatever idyllically (whatever that means) on breadfruit and poi (whatever those are). More-or-less correct usage often precedes referential those are). More-or-less correct usage often precedes referential knowledge, which itself can remain vague but connotatively knowledge, which itself can remain vague but connotatively useful. Thus the frequent arguments over the meaning of words useful. Thus the frequent arguments over the meaning of words and the livelihood of lexicographers and language columnists and the livelihood of lexicographers and language columnists who educate us about words we already partially know. who educate us about words we already partially know. Moreover, knowing in what contexts to use a word can function Moreover, knowing in what contexts to use a word can function to amplify learning more about it by a bootstrapping operation in to amplify learning more about it by a bootstrapping operation in which what happens in response provides new context if not which what happens in response provides new context if not explicit verbal correction. (Landauder & Dumais 1996)explicit verbal correction. (Landauder & Dumais 1996)

What’s Important about What’s Important about Categorization?Categorization?

Most words refer to classes rather than Most words refer to classes rather than to specific entities. to specific entities.

Perception, motor activity, linguistic Perception, motor activity, linguistic behavior all involve categories.behavior all involve categories.

Inference is based on categorization Inference is based on categorization (e.g., Linnaean taxonomy, Euler’s (e.g., Linnaean taxonomy, Euler’s formula: V-E+F=2, medical diagnosis.formula: V-E+F=2, medical diagnosis.

Categories and category boundaries Categories and category boundaries matter in the search for universals of matter in the search for universals of human cognition.human cognition.

The Classical Model of The Classical Model of CategorizationCategorization

The folk model based on common The folk model based on common properties (conditions) is also the properties (conditions) is also the classical model. classical model.

Categories have no internal structure; Categories have no internal structure; all members are equal.all members are equal.

Categories are based on inherent Categories are based on inherent properties. properties.

Humans have access to category Humans have access to category structure, but may make naïve errors.structure, but may make naïve errors.

The Classical ModelThe Classical Model

Reason is the mechanical manipulation of Reason is the mechanical manipulation of abstract symbols. abstract symbols.

Symbols get their meaning from their Symbols get their meaning from their ability to refer to things in the world or a ability to refer to things in the world or a possible world. possible world.

The meaning of a sentence is the set of The meaning of a sentence is the set of condition(s) under which it is true or false.condition(s) under which it is true or false.

Questioning the classical model of Questioning the classical model of categorization is questioning the classical categorization is questioning the classical view of reasoning.view of reasoning.

The Classical ModelThe Classical Model

My proposals will also not conform to the My proposals will also not conform to the expectations of those who, in analyzing meaning, expectations of those who, in analyzing meaning, turn immediately to the psychology and sociology of turn immediately to the psychology and sociology of language users: to intentions, sense-experience, and language users: to intentions, sense-experience, and mental ideas, or to social rules, conventions and mental ideas, or to social rules, conventions and regularities. I distinguish two topics: first, the regularities. I distinguish two topics: first, the description of possible languages or grammars as description of possible languages or grammars as abstract semantic systems whereby symbols are abstract semantic systems whereby symbols are associated with aspects of the world; and second, associated with aspects of the world; and second, the description of the psychological and sociological the description of the psychological and sociological facts whereby a particular one of these abstract facts whereby a particular one of these abstract semantic systems is the one used by a person or semantic systems is the one used by a person or population. Only confusion comes of mixing these population. Only confusion comes of mixing these two topics. —David Lewis, “General Semantics” two topics. —David Lewis, “General Semantics” (1972)(1972)

Questioning the Questioning the Classical ModelClassical Model

Human categorization is essentially a Human categorization is essentially a matter of human experience and matter of human experience and imagination—of imagination—of perceptionperception, , motor activitymotor activity and and culture culture (on the one hand) and of (on the one hand) and of metaphormetaphor, , metonymymetonymy and and mental mental imageryimagery on the other (on the other). on the other (on the other).

To change our view of categories is to To change our view of categories is to change our view of the world, since change our view of the world, since categories are categories of things: categories are categories of things: species, substances, artifacts, colors, species, substances, artifacts, colors, kinsmen, emotions, etc.kinsmen, emotions, etc.

Stereotypes Associated Stereotypes Associated with the Classical Modelwith the Classical Model

Meaning is based on truth and reference.Meaning is based on truth and reference. The mind is independent of the body.The mind is independent of the body. Reason transcends human concerns.Reason transcends human concerns. Only reason has conceptual content.Only reason has conceptual content. Language is a poor window into cognitive Language is a poor window into cognitive

processing, because it tends to be sloppyprocessing, because it tends to be sloppy ..

The Alternative ModelThe Alternative Model

Every category has a Every category has a prototypical member prototypical member and and belongs to abelongs to a taxonomy. taxonomy.

Prototypes give rise to:Prototypes give rise to: membership gradiencemembership gradience markedness in language markedness in language polysemy in languagepolysemy in language contested categories contested categories generativitygenerativity reference-point (metonymic) reference-point (metonymic)

reasoningreasoning

The History of Prototype The History of Prototype TheoryTheory Prototype theory can trace its origins back Prototype theory can trace its origins back

to late work of to late work of Ludwig WittgensteinLudwig Wittgenstein.. Philosophical InvestigationsPhilosophical Investigations (1953): Words (1953): Words

are not defined by reference to objects in are not defined by reference to objects in the external world or by mental the external world or by mental representations, but rather by how they are representations, but rather by how they are used in effective, ordinary communication.used in effective, ordinary communication.

His famous example is the category GAME.His famous example is the category GAME. How can GAME be defined in such a way as How can GAME be defined in such a way as

to include basketball, solitaire, tag, musical to include basketball, solitaire, tag, musical chairs and chess?chairs and chess?

Application to CategoriesApplication to Categories

There may be no property which There may be no property which characterizes all members of a category, characterizes all members of a category, whether necessary or sufficient. whether necessary or sufficient.

This doesn’t entail that the category has This doesn’t entail that the category has unclear boundaries: GOE ≠ DOM (C&C, p. unclear boundaries: GOE ≠ DOM (C&C, p. 79)79)

It does mean that the category label may It does mean that the category label may be extensible.be extensible.

The SALAD exampleThe SALAD example

Radial CategoriesRadial Categories

Lakoff proposes a model of category Lakoff proposes a model of category structure to explain (most) prototype structure to explain (most) prototype effects: the best exemplar is defined effects: the best exemplar is defined by a cluster of converging properties. by a cluster of converging properties.

Peripheral members lack one or more Peripheral members lack one or more of the properties that define the central of the properties that define the central member. member.

Occasionally, there is also chaining Occasionally, there is also chaining within a category (e.g., Jello salad is within a category (e.g., Jello salad is chained to lettuce salad via fruit salad). chained to lettuce salad via fruit salad).

PolysemyPolysemy

J.L. Austin (1961) asked, “Why do we call J.L. Austin (1961) asked, “Why do we call different kinds of things by the same name?” different kinds of things by the same name?”

He argued that neither similarity or He argued that neither similarity or equivocation were involved. equivocation were involved.

The word The word healthyhealthy: : healthy bodyhealthy body vs. vs. healthy healthy activityactivity vs. vs. healthy complexionhealthy complexion

Fillmore on Fillmore on climbclimb: : The airplane climbed to The airplane climbed to 30,000 feet30,000 feet vs. vs. She climbed out onto the She climbed out onto the balcony.balcony.

Category Boundaries are Category Boundaries are ExtensibleExtensible

Lounsbury: Fox skewing rules (e.g., Lounsbury: Fox skewing rules (e.g., merging merging rulerule: X’s same sex sibling can be referred to : X’s same sex sibling can be referred to by X’s title; mother’s sister= mother). by X’s title; mother’s sister= mother).

Berlin & Kay (1967): languages don’t carve up Berlin & Kay (1967): languages don’t carve up color spectrum randomly. Hierarchy of basic color spectrum randomly. Hierarchy of basic color terms via agreement on best exemplars. color terms via agreement on best exemplars.

• black, whiteblack, white• redred• yellowyellow, , blueblue, , greengreen• brownbrown• purplepurple, , pinkpink, , orangeorange, , graygray

Rosch on PrototypesRosch on Prototypes

What Rosch describes are asymmetries What Rosch describes are asymmetries that she calls prototype effects: that she calls prototype effects: subjects judged members of some subjects judged members of some categories as more representative than categories as more representative than others.others.

Paradigms included: direct rating, Paradigms included: direct rating, reaction time, production of examples, reaction time, production of examples, asymmetry in similarity ratings, asymmetry in similarity ratings, directionality of generalizations.directionality of generalizations.

Rosch on PrototypesRosch on Prototypes

Rosch initially attributed the effects as Rosch initially attributed the effects as caused by perceptual salience, then as a caused by perceptual salience, then as a theory of category structure, then as theory of category structure, then as having many underlying causes.having many underlying causes.

Barsalou on Barsalou on ad hocad hoc categories. categories. Linguistic prototype effects: are subjects’ Linguistic prototype effects: are subjects’

hesitations to apply a given label due to hesitations to apply a given label due to gradience or goodness of fit? (e.g., gradience or goodness of fit? (e.g., lielie))

How does How does metonymymetonymy interact with a interact with a theory of prototypes? theory of prototypes?

The Basic LevelThe Basic Level

Roger Brown: “While a dime can Roger Brown: “While a dime can be called a coin or money or a be called a coin or money or a 1952 dime, we somehow feel 1952 dime, we somehow feel that dime is its real name”.that dime is its real name”.

Categorization “begins at the Categorization “begins at the level of distinctive action”; level of distinctive action”; superordinate and subordinate superordinate and subordinate names are “achievements of the names are “achievements of the imagination”. imagination”.

The Basic LevelThe Basic Level

It is the level of distinctive actions.It is the level of distinctive actions. It is the level which is learned It is the level which is learned

earliest and at which things are earliest and at which things are first named.first named.

It is the level at which names are It is the level at which names are shortest, most frequent, and least shortest, most frequent, and least likely to be borrowed.likely to be borrowed.

It is the highest level at which a It is the highest level at which a single image can stand for the single image can stand for the whole. whole.

The Basic LevelThe Basic Level

It is the level at which folk It is the level at which folk categories correspond most categories correspond most closely to scientific categories.closely to scientific categories.

It is the level with the greatest It is the level with the greatest cultural significance.cultural significance.

It is the level at which It is the level at which distinctions are made most distinctions are made most easily.easily.

It is the level at which most the It is the level at which most the knowledge is concentrated. knowledge is concentrated.

Prototypes and Prototypes and the Basic Levelthe Basic Level

How do prototype-based How do prototype-based categories interact with categories interact with basic-level categories?basic-level categories?

Are they the same thing?Are they the same thing? Could there be prototype Could there be prototype

effects are all levels in a effects are all levels in a taxonomy?taxonomy?

What does it really mean for What does it really mean for a single image to stand for a single image to stand for the whole category?the whole category?

Linguistic Linguistic Prototype EffectsPrototype Effects

We often refer to linguistic categories We often refer to linguistic categories as as markedmarked or or unmarkedunmarked..

What does this mean?What does this mean? Are there numerous conceptions of Are there numerous conceptions of

markedness?markedness? Is markedness a useful concept in Is markedness a useful concept in

linguistics?linguistics?

Shortcomings of Shortcomings of Prototype Theory (Croft Prototype Theory (Croft

& Cruse 4)& Cruse 4) The features used are not context The features used are not context sensitive. sensitive.

Features may not vary independently. Features may not vary independently. Features may need to be weighted to Features may need to be weighted to

distinguish basic-level categories from one distinguish basic-level categories from one another.another.

Features need to be ‘grounded’ in order to Features need to be ‘grounded’ in order to be meaningful.be meaningful.

But But framesframes can behave like features, as in can behave like features, as in Lakoff’s account of the category MOTHER.Lakoff’s account of the category MOTHER.

A Dynamic Model of A Dynamic Model of PrototypesPrototypes

Smith & Samuleson (1997) are critical Smith & Samuleson (1997) are critical of the ‘fixed categories’ approach. of the ‘fixed categories’ approach.

They argue that categories are created They argue that categories are created based on life experience, priming and based on life experience, priming and current plans and goals.current plans and goals.

All three phenomena come into play in All three phenomena come into play in the the determination ofdetermination of boundariesboundaries, , framingframing and and level of categorizationlevel of categorization..

BoundariesBoundaries

Context determines the placement of Context determines the placement of a category boundaries.a category boundaries.

The following don’t appear to qualify The following don’t appear to qualify as games, but in some contexts may as games, but in some contexts may be considered as such:be considered as such: A jigsaw puzzle (no active agent against A jigsaw puzzle (no active agent against

whom one competes)whom one competes) Roulette (goals external to the activity)Roulette (goals external to the activity) A race (player cannot interfere with A race (player cannot interfere with

opponent)opponent)

FramesFrames

Peripheral members of a category may Peripheral members of a category may be central depending on the frame be central depending on the frame invoked. invoked.

Pizza is a prototypical breakfast if the Pizza is a prototypical breakfast if the ‘timed meal’ frame is invoked. ‘timed meal’ frame is invoked.

A genetic mother is prototypical if the A genetic mother is prototypical if the hereditary disease frame is invoked. hereditary disease frame is invoked.

A guide dog or a horse is a prototypical A guide dog or a horse is a prototypical pet if not ‘functional’, thereby pet if not ‘functional’, thereby promoting the ‘companion’ frame. promoting the ‘companion’ frame.

Level of CategorizationLevel of Categorization

What constitutes the basic level vs. the What constitutes the basic level vs. the superordinate level is not merely a function of superordinate level is not merely a function of expertise. expertise.

One’s purpose in categorizing may influence One’s purpose in categorizing may influence the ‘granularity’ of perspective that one the ‘granularity’ of perspective that one takes. takes.

Framing influences level of categorization; Framing influences level of categorization; these superordinates act like basic-level these superordinates act like basic-level terms:terms: beverage (in a restaurant frame)beverage (in a restaurant frame) produce (in a grocery store)produce (in a grocery store) liquid (at airport security ) liquid (at airport security )