Most actual cases of prototype phenomena simply are not used in “identification”. They are used instead in thought-making inferences, doing calculations, making approximations, planning, comparing, making judgments-as well as in defining categories, extending them, and characterizing relations among subcategories. Prototypes do a great deal of the real work of the mind and have a wide use in rational processes.
- Lakoff (1987), a pag.145

Given the various possible category structures, prototype effects can arise in a number of ways:- Metonymy: Given category B, where A is either a member or subcategory of B, suppose that A metonymically “stands for” B. That is, it is either a social stereotype, or a typical case, or an ideal, or a submodel, etc. Then A will be a best example of B.- Radial Category: Given category B with a radial structure and A as its center, then A is the best example of B.- Generative Category: Suppose B is a category generated by rule from a subcategory or member, A. Then A is a best example of B.- Graded Category: Given a graded category B with A being a member of degree 1, then A is a best example of B.- Classical Category: Consider a cognitive model containing a feature bundle that characterizes a classical category B. If A has all the properties in the feature bundle, it is a best example of B. An element C, having some of the properties in the feature bundle, may be judges a less-good example of B. Strictly speaking, C will be outside B; but people, in such cases, may consider B a graded category, such that elements bearing a degree of similarity to members of B will be viewed as being members of B to a degree.
- Lakoff (1987), a pag.288-289

Prototype structure also testifies to imaginative processes of many kinds: metonymy (the capacity to let one thing stand for another for some purpose), the ability to construct and use idealized models, and the ability to extend categories from central to noncentral members using imaginative capacities such as metaphor, metonymy, mythological associations, and image relationships.
- Lakoff (1987), a pag.371