The development of the beliefs, moods, and behaviors that differentiate among people.

The concept of personality refers to the profile of stable beliefs, moods, and behaviors that differentiate among children (and adults) who live in a particular society. The profiles that differentiate children across cultures of different historical times will not be the same because the most adaptive profiles vary with the values of the society and the historical era. An essay on personality development written 300 years ago by a New England Puritan would have listed piety as a major psychological trait but that would not be regarded as an important personality trait in contemporary America.

Contemporary theorists emphasize personality traits having to do with...