A commonly used term for adults or children who are quiet, reserved, thoughtful, and self-reliant and who tend to prefer solitary work and leisure activities.

Individuals who are quiet, reserved, thoughtful, and self-reliant are often referred to as "introverts." They are likely to prefer solitary work and leisure activities. In comparison with extroverts, who draw most of their energy from social interaction and respond to external stimuli immediately and directly, introverts tend to mull things over before formulating a reaction, and their energy is regenerated by time spent alone.

Carl Jung was the first psychologist to use the terms introversion and extroversion, which literally mean "in- ward turning" and "outward turning." More recently, researchers in the field of personality, most notably Hans Eysenck, have popularized these terms. Eysenck claims a biological basis for introversion and extroversion, rooted in differences in sensitivity to physical and emotional stimulation. Eysenck claims...