This experiment tested two hypotheses: 1) that categories represented by features that many people believe to be necessary will demonstrate stronger category contrast than those represented by features that few people believe to be necessary, and 2) that categories that people believe are represented primarily by intrinsic features (i.e., features true of an entity in isolation) will have stronger category contrast than those that people believe are represented primarily by extrinsic features (i.e., features that represent relations between an entity and other entities). The findings support only the second hypothesis.