Concept, a mental representation used for a variety of cognitive functions. Categorization, the processes by which things are placed into groups. Pointers of knowledge once you know something is in a category, you know a lot of general things about it. Definitional approach to categorization, we can decide whether something is a memory of a category by determining whether a particular object meets the definition of the category. Problem, not all members of everyday categories have the same features. Family resemblance, the idea that things in a particular category resemble one another in a number of ways. Prototype approach to categorization, membership in a category is determined by comparing the object to a prototype that represents the category. Prototype, a typical member of the category. Not an actual member of the category, is an average representation of the category. High prototypicality means that a category member closely resembles the category prototype.