In this chapter you read about how personality can be described, why individuals differ in personality, and how such differences might be understood in terms of mental processes. Two general ideas might help you organize your thinking as you review the particular ideas of the chapter.
1. The varying purposes of personality theories Different personality theories have been developed to serve different purposes. Trait theorists try to distill the essential personality dimensions common to all people, while clinical theorists try to discover the mental processes and beliefs that help or hinder people in coping with life’s demands.
Trait theories, such as the five-factor model, are attempts to describe the diversity of human personality objectively and efficiently, by identifying sets of nonredundant global traits and ways to measure them. The trait measures, usually made with questionnaires, are used in studies comparing one group of people with another, such as men with women, or people in one career with those in another. Trait theories do not explain personality; they only describe its elements.
Psychodynamic, humanistic, and social-cognitive theories, in contrast, were designed to explain the particular behaviors, emotions, and thoughts of individual people, especially of people undergoing psychotherapy. Psychodynamic theories explain personality in terms of unconscious motives and defenses against anxiety. Humanistic theories explain personality in terms of people’s subjective understanding of their world and themselves and their strivings for self-actualization. Social-cognitive theories also attempt to explain the behavior of individuals in terms of their beliefs but take a less holistic approach than do either humanistic or psychodynamic theories. Social-cognitive theorists are more often academic research psychologists than clinicians, and their interest tends to center more on a specific mental construct (such as locus of control) than on individuals as whole entities.
2. Adaptive functions of individual differences Because of the close tie between personality research and clinical research, personality theories have often been concerned with distinctions between healthy (or adaptive) and unhealthy (or maladaptive) personality styles. This concern is reflected in such distinctions as that between mature and immature defenses or between adaptive and maladaptive forms of optimism. An alternative way to think about personality differences, however, is to view them as adaptations to different niches or as different strategies for solving life’s problems. In this way of thinking, two quite different styles might be equally healthy or adaptive. In this chapter you saw examples of this idea reflected especially in research and theories concerning animal personality types and sibling and gender differences in personality.
As you review each of the dimensions of personality differences discussed in the chapter—including differences in defensive style, locus of control, optimism versus pessimism, and collectivism versus individualism, as well as the Big Five traits—think about ways in which variation in either direction could be either adaptive or maladaptive, depending on one’s life circumstances.