1. Prototype Categories: I
Taylor 3
Prototype Categories: I

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

3. 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

4. 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 +/-)

5. 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”

6. 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

7. 3.3 Basic level terms Superordinate level Basic level
Subordinate level
Artefact
Furniture
Chair
Kitchen chair
This kitchen chair

8. 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.”

9. 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)

10. 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

11. 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

12. 3.4 Why prototype categories?
Advantages of prototypicality
Much more flexible than Aristotelian categories
Can accommodate new data

13. 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)

14. 3.5 A note on fuzziness
Prototypicality is not mere gradience

15. 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)