This paper is an examination of the concept of personality. Psychologists disagree on the number of elements that are key to defining personality. Some contend that only two factors are needed to analyze the essential qualities that distinguish an individual's particular styles of thought, behavior, and emotions, while others argue for between five and 13 distinctive scales for defining personality. Psychologists also disagree on the extent to which personality traits are part of an individual's genes, rather than being influenced by environmental factors. Psychologists debate the permanence of personality: will an introvert always remain essentially introverted, even if he or she learns to behave in an outgoing way? Personality, more than any of the other differences among individuals, is especially difficult to study objectively, since the personality of the scientist inevitably becomes part of the research. Nevertheless, insights into personality provide invaluable information, useful to everyone who deals with other human beings, from international diplomats to the parents of an adolescent. Understanding the roots of personality differences can also be extraordinarily illuminating for the individual who seeks to understand his or her own motivations and ways of dealing with the world.
Although individuals can be classified according to physical and genetic differences, one of the most striking distinctions that psychologists are concerned with is the collection of qualities known as personality. Henry Gleitman (1996) describes these qualities as the "predominant desires, . . . characteristic feelings, and . . . typical modes of expressing these desires and feelings" (p. 521), while Camille B. Wortman and Elizabeth F. Loftus (1988) describe personality as "all the relatively stable and distinctive styles of thought, behavior, and emotional response that characterize a person's adaptations to surrounding circumstances" ...