Exemplar theory

Exemplar Theory is a proposal concerning the way humans categorize objects and ideas in psychology. It argues that individuals make category judgments by comparing new stimuli with instances already stored in memory. The instance stored in memory is the . The new stimulus is assigned to a category based on the greatest number of similarities it holds with exemplars in that category. For example, the model proposes that people create the “bird” category by maintaining in their memory a collection of all the birds they have experienced: sparrows, robins, ostriches, penguins, etc. If a new stimulus is similar enough to some of these stored bird examples, the person categorizes the stimulus in the “bird” category. Various versions of the exemplar theory have led to a simplification of thought concerning concept learning, because they suggest that people use already-encountered memories to determine categorization, rather than creating an additional abstract summary of representations.

Exemplar Theory is often contrasted with prototype theory, which proposes another method of categorization. We use both the exemplar and prototype method in making category judgments, and they often work in tandem to produce the most accurate conclusion. The two theories are similar in that they emphasize the importance of similarity in categorization: only by resembling a prototype or exemplar can a new stimulus be placed into a category. They also both rely on the same general cognitive process: we experience a new stimulus, a concept in memory is triggered, we make a judgment of resemblance, and draw a categorization conclusion. However, the specifics of the two theories are different. Prototype theory suggests that a new stimulus is compared to a single prototype in a category, while exemplar theory suggests that a new stimulus is compared to multiple known exemplars in a category. While a prototype is an abstract average of the members of a category, an exemplar is an actual member of a category, pulled from memory. While prototypes are economical—meaning they are more conducive to quick judgments—exemplars are less so. On the other hand, prototypes are less flexible than exemplars: exemplars can account more easily for atypical category members, such as a penguin being part of the “bird” category, because an exemplar does not average out the characteristics of a category like a prototype does. Exemplars can make sense of variable categories—those with less distinguished characteristics—such as “games”, much more so than prototypes, which rely on typical characteristics to determine membership. Another difference, suggested by research, is that exemplars are more likely to be used than prototypes after long experience with a concept.

...
Wikipedia