According to the instantiation principle, the representation of a category includes detailed information about its diverse range of instances. Many accounts of categorization, including classical and standard prototype theories, do not follow the instantiation principle, because they assume that detailed, exemplar-level information is filtered out of category representations. Nevertheless, the instantiation principle can be implemented in a wide class of models, including both exemplar and abstraction models. To assess the instantiation principle empirically, a parameter-free exemplarbased model of instantiation was applied to typicality judgments for 16 simple categories (e.g., mammal, beverage) and 14 complex categories (e.g., dangerous mammal) in four superordinates (animal, food, small animal, dangerous animal). Across three studies, the model did an excellent job of predicting mean typicality judgments (correlations generally above .9) and a good job of predicting standard deviati...