Relates to the phenomenon whereby a particular instance or exemplar is judged as being more or less representative of a given category.

Typicality effects are held, in prototype theory, to result from the prototype structure of human categories and are measurable by goodness-of-example ratings. For instance, while a robin, for many people, might be judged to be a representative example of the category bird, ostrich would be judged to be not very representative and thus non-typical. These differential judgments in terms of representativeness are what are known as typicality effects.