Learning process by which items are categorized and related to each other.

A concept is a generalization that helps to organize information into categories. For example, the concept "square" is used to describe those things that have four equal sides and four right angles. Thus, the concept categorize things whose properties meet the set requirements. The way young children learn concepts has been studied in experimental situations using so-called artificial concepts such as "square". In contrast, real-life, or natural, concepts have characteristic rather than defining features. For example, a robin would be a prototypical or "good" example of the concept "bird." A penguin lacks an important defining feature of this category—flight, and thus is not as strong an example of a "bird." Similarly, for many children the concept "house" represents a squarish structure with walls, windows, and a chimney that provides shelter. In later development...