This paper gives an account of
how prototypes constitute a full-defined category, and how a
man makes use of it to expedite his categorization. We clarify
these points referring to the problem of whether a category is
formed with the notion of resemblance with a concrete prototypical
member of a category or extracted with an abstract schema.
We discuss the prototype theory
of mental categories in light of our experimental findings of
full-defined categories in three types.
The well-defined categories of
infinite members such as "odd number" and "even
number" are constructed based on their definition, and the
members involved in this definitions easily become prototypes.
To define "odd number" category, it is necessary to
adopt the number 2, which is also a prototype of this category.
In the categories which consist
of circulation-free, finite members, such as "blood group"
and "professional baseball team", all of the category
members are involved in the definition of them. Therefore, prototypes
are not always necessary to form categories in these cases. Moreover,
there is room to yield hierarchy of membership by means of speakers'
subjectivity like 'my blood group' and 'my favorite baseball
Lastly, in categories with circulation,
finite members, such as "days of the week" and "months
of the year", one often conceptualize categories as linear
structure of ordered members with having a clue in the starting
point and in the endpoint of the circulation. All of the members
are involved in the definition of the category. In this case,
the members at the starting point and at the endpoint often become
prototypes of that category.
Consequently, prototypes are not
always functioning as basic cognitive cores in constructing categories.
Especially in full-defined categories, it was clarified that
prototypes do not play central roles to form the categories.
Full-defined categories with finite members are defined with
giving the holistic lists of the members, while categories with
numerous or infinite members are defined with the categorical
definition, not with the lists of category members.