The Concept of Basic-Level Categorization

One characteristics of real world, or natural categories is that they are hierarchical-larger categories contains smaller categories. For example, the category clothing contains pants, and the category pants contain Levi's. Each of the level contains a variety of objects, but the variety decreases as the category becomes smaller. The largest categories are the superordinate categories, such as tools and clothing. Superordinate categories contain the basic level categories, such as hammer, which in turn contains the subordinate categories, such as claw hammer. According to Rosch, basic level categories are the most differentiated from one another; therefore the basic categories are the first category we learn.

Basic level concepts are the main level which we use in the day-to-day living. The basic level categories not only share many attributes but also have attributes that differ from those of items in other basic-level categories. Rosch tested her claim that categorization is fastest at the basic level, by asking to verify the identity of an object at each of the three level in the hierarchy. For instance, before being shown a picture of a folk guitar, people given superordinate terms were asked whether the objects was a musical instrument, people of the basic level asked whether object was a guitar and the subordinate terms asked whether it was a folk guitar. Rosch found out that the fastest verification times occurred for the group that verified objects at the basic level. Rosch proposed that people identify objects at the basic level and then classify them to superordinate or subordinate level.

Objects in categories can be represented by prototype. The prototype of a category is usually defined as the "average" of the patterns in the category. Prototype could be defined as an item that typifies the members in a category and is used to represent the category. The concept of an average example becomes meaningful if we think of objects from the same basic level. For example, the average of two chairs still looks reasonably like a chair, and the average of two shirts still looks reasonably like a shirt. Creation of an average patterns to represent a category therefore possible at the basic-level.

Basic-level categories is also the level at which categories are the most differentiated from one another, because the members of the basic level categories share many attributes