Prototype Categories: I Taylor 3 Prototype Categories: I

What kind of categories? This chapter will look at empirical findings which indicate a need for a non-Aristotelian theory of categorization.

3.1 Wittgenstein Definition of game as “family resemblance” Category members do not share a set of common properties There is no clear boundary The vast majority of words behave this way Meanings are learned on the basis of exemplars

3.2 Prototypes: an alternative to the classical theory Labov: an empirical study of cup, mug, bowl, vase No clear dividing line between categories What items were filled with influence category decisions (human interaction) Each category has optimal members Attributes are not semantic primitives (they are gradual, not +/-)

Eleanor Rosch Category membership is determined by relationship to a prototype Various categories (eg. furniture) yield statistically reliable ratings of how good a given exemplar is “degree of membership in a category, far from being meaningless, is in fact a psychologically very real notion”

Eleanor Rosch, cont’d A diverse range of categories yields the same results Degree of membership is verified by a variety of experiments Central members are identified more quickly, named first, learned faster, yield stronger inferences

3.3 Basic level terms Superordinate level Basic level Subordinate level Artefact Furniture Chair Kitchen chair This kitchen chair

3.3 Basic level terms, cont’d. The level that is semantically simplest is not the lowest (or most primitive) – it is the basic level “It is at the basic level that people conceptualize things as perceptual and functional gestalts.”

3.3 Basic level terms, cont’d. Have high frequency of occurrence Are short and structurally simple (monomorphemic) Subordinate terms usually include a modifier Superordinate terms are often deviant (eg. uncountable furniture)

3.3 Basic level terms, cont’d. Are maximally useful: A) maximize the number of attributes shared by members of the category B) minimize the number of attributes shared with members of other categories The basic level is also where we see most obvious prototype effects

3.4 Why prototype categories? Sources of prototypicality Perceptual salience Frequency of encounter (may be a symptom, not a cause) Order of learning Cultural importance

3.4 Why prototype categories? Advantages of prototypicality Much more flexible than Aristotelian categories Can accommodate new data

3.4 Why prototype categories? “Prototype categories give us the best of both worlds. The central members do share a large number of attributes – in this respect, the center of a prototype category approaches the ideal of a classical category. At the same time, prototype categories permit membership to entities which share only few attributes with the more central members. In this respect, prototype categories achieve the flexibility required by an ever-changing environment.” (p. 54)

3.5 A note on fuzziness Prototypicality is not mere gradience

3.6 Some applications Different languages might have different prototypes (cf. Eng furniture and German moebel – American students imagined their parents’ living rooms and German students imagined a student’s room) Prototypes can change with time (eg. car, bicycle)