Prototypes

Definition

A prototype is the best or most central member of a category. An object can be described in terms of prototypicality, which refers to the degree to which it is a good example of a category. For example, baseball is a more prototypical sport than is billiards or bullfighting, and an automobile is a more prototypical vehicle than is a sled or skateboard.

Background

The idea that category members differ in how well they fit their category is an important component of what is known as the natural view of categories, which emerged in the 1950s with the publication of Ludwig Wittgenstein's Philosophical Investigations. Radically transforming how categories were understood, the natural view replaced the classical view, a perspective originating from Aristotle's thinking about categories that had been the accepted belief for two millennia.

According to the classical view, a category, like a formal set, has specific defining characteristics that make the determination of category membership unambiguously clear. Objects that possess all the defining characteristics are category members and objects that do not are nonmembers. Having an absolute criterion for category membership implies that there is no gradation among category members. All objects that meet the standard for inclusion are equivalently good category members. The classical view also assumes that categories are arbitrary, as expressed in Benjamin Lee Whorf's writing on language and thought, which portrays categorization as a linguistic community's agreement about how to organize its otherwise chaotic reality. In this view, a category is merely sociolinguistic convention, without any inherent order or constraint in which attributes cluster together to define it.

The Natural View and Categorization

Despite its longevity, the classical view ultimately gave way because the natural view better describes how people actually categorize objects. The natural view recognizes that most categories are not defined by a set of specific properties that are true of all category members. Instead, category members are linked by family resemblance, a group of related characteristics that category members will likely, but not necessarily, possess. For example, a number of things are typically found on vehicles, such as wheels and a motor. However, none of these typical attributes are found on all vehicles, and there is no essential characteristic that an object must possess to be categorized as a vehicle.

Family resemblance implies that category members may not be equivalent. When individual category members possess some but not all of the category's common features, an object with more of these common features will be considered a better example of the category than one that has fewer. Natural categories have an internal structure, with the prototype, or best example of the category, at the center and less prototypical objects radiating away from it. Although the category's center is clear, its boundaries are fuzzy. There is no definite point at which one can say the category ends. People will agree about the status of most objects. Things like cars and bicycles are clearly vehicles, but coffeepots and neckties are obviously not. However, at the margins of a category, there will be objects whose status is unclear. People will disagree about whether things like a wheelbarrow, an elevator, or a pair of skates can be considered a vehicle. According to the natural view, no absolute boundary divides the things that are vehicles from those that are not.

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