CATEGORIZATION

CATEGORIZATION

1. The classical theory

   • Aristotle
     • Essence: that which makes a thing what it is.
       • Accident: incidental propertie which plays no part in determining what the thing is.
   • Characteristics:
     • 1) Categories are defined in terms of a conjunction of necessary and sufficient features.
       • 2) Features are binary.
         • 3) Categories have clear boundaries.
           • 4) All members of a category have equal status.
             • 5) Features are primitive.
               • 6) Features are universal.
                 • 7) Features are abstract.
                   • 8) Features are innate.
     • Advantages for the categories of semantics:
       • 1) One is able to state the proportional relations which exist within the lexicon. 2) Features make it possible to define natural classes of items. 3) It throws light on certain kinds of sentence meaning, and on the meaning relationships that exist.
       • Disadvantages for the categories of semantics:
         • The number of semantic categories in any one language is not only inmense, but also extendible, and it would seem unrealistic to expect to be able to reduce all passible word meanings to a manageable, finite set of universal primitives.

2. Prototype Categories

   • The category is not structured in terms of shared criterial features, but rather by a criss-crossing network of similaritites (family resemblances).
     • Characteristics:
       • 1) Attributes are not binary constructs.
         • 2) Attributes, far from being the abstract entities of autonomous linguistics, are properties of real-world entities which are readily accessible.
           • NOTE: Attributes have to do, not with inherent properties of the object itself, but with the role of the object whithin a particular culture.
           • 3) Following 2), the attributes cannot be regarded as semantic primitives.
             • 4) Not one single attribute is essential for distinguishing the one category from another.
               • 5) Membership in prototype category is a matter of gradience.
   • Prototypes serve as reference points for the categorization of non-so-clear instances. Categories typucally have fuzzy edges and might even merge into each other; some attributes might be shared by only a few members of a category, etc.
     • The category name activates the names of more prototypical members of the category, and deactivates the more marginal members.
       • Basic level categories
         • a) Maximize the number of attributes shared by members of the category; and b) minimize the number of attributes shared with members of other categories.
         • How does it work?
           • The closer an entity to the prototype, the more central its status within the category. Meaning that things can be more similar or less similar.
             • "Similarity, like beauty, lies in the eye of the beholder".
             • The model would compute a numerical value of similarity with the prototype representation.
               • Attributes are simply the dimensions along which different entities are regarded as similar. All members of the category share at least one criterial attribute, plus the attributes are differentially weighted.
           • About the schemas
             • A schema is an abstract characterization that is fully compatible with all the members of the category it defines. Schemas are hierarchically organised within the category, in conjunction with extension from prototypes.
               • Categorization by prototype and categorization by schema are, in reality, aspects of the same phenomenon.