Prepared as a chapter for the Annual Review of Psychology, 1995.
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Individual differences research is not the same as theories of personality of the individual (Rorer 1990). A person is not just the simple combination of universals of human nature and specific values on two, three, five or even ten independent trait dimensions. A person is also a dynamic information processor whose unique memories and perceptual structures lead to a unique cognitive, affective, and behavioral signature. Structural studies of individual differences emphasize between subject correlational patterns of variables. But these structures are not the same as studying the coherent patterns of an individual over a lifetime, or even across different situations (York & John 1992). Those theorists emphasizing uniqueness have tended to be more cognitively oriented than are the biologically oriented trait theorists, or the pragmatic psychometricians concerned with cross situational prediction.
Social-cognitive theorists emphasize the dynamic and flexible use of multiple cognitive structures as one solves the problems of day to day interaction. Although recognizing the importance of dispositional structures (traits), the focus is on the adaptive use of schemas, tasks, and strategies (Cantor 1990). Schema driven processing describes the assimilation of new information into existing cognitive structures and recognizes that physically identical inputs will lead to dramatically different outputs depending upon prior knowledge and beliefs. Although this cognitive orientation at first seems different from the dispositional approach, in fact, biological theorists also suggest that information is processed differently according to existing structures (e.g., Gray's description of anxiety and impulsivity as sensitivities to cues for punishment and reward.) The difference is thus one of emphasis upon the particular schemas, tasks and strategies that one uses rather than on the determination of the causes for differences.
Although it is logically possible to study the effects of unique organizations of biological structures (anatomical texts emphasize the similarities of structure, but anatomists quickly realize the variation and unique patterning that exists), the primary emphasis upon individuality is expressed by those studying cognitive structures and processes. By emphasizing the uniqueness of individual construals, cognitive theorists attempt to move beyond the "psychology of the stranger" (McAdams 1994b) characteristic of trait theory and instead study the personality of individuals.
The study of cognitive aspects of personality is not new (Kelly 1955) but has become a focal point of social-cognitive theorists as they apply cognitive theory to the study of individuality. People are seen as active processors of information, forming, testing and acting on hypotheses about their selves and others. This active social construal process can be seen as the basis of the lexical hypothesis that individuals will code important phenomenon linguistically. What is important to people in the aggregate becomes coded into the language.
The multiple hypotheses one has about one's self guide one's perceptions, thoughts, and actions. Self is the insider's view of personality (Markus & Cross 1990). As a fundamentally social construal (Banaji & Prentice 1994), the "working self-concept is influential in the shaping and controlling of intrapersonal behavior (self-relevant information processing, affect regulation; and motivational processes) and interpersonal processes, which include social perception, social comparison, and social interaction" (Markus & Cross 1990, p 578). One's theory of intelligence guides one's responses to success and failure and resulting school achievement (Dweck 1991), and a negative self-concept leads to seeking self-verification through failure (Swann 1992).
Changes in interpreting motivational phenomena such as arousal in terms of metamotivational states (e.g., the telic state that emphasizes goal driven behaviors versus the paratelic state that emphasizes the behaviors themselves) can lead to dramatic "reversals" of thought and action (Apter 1989). When in a telic state of trying to achieve an important goal, high arousal is associated with anxiety and low arousal with relaxation. In contrast, when in a paratelic state of playfulness, high arousal is exciting and low arousal is boring. Phenomenological interpretation of a situation affects physiological responses in that situation (Apter & Sveback 1992).
The dynamic pattern of reversals over time that occur in a constant situation are reminiscent of those modeled by the dynamics of action (Atkinson & Birch 1970; Revelle 1986). Although the emphasis in reversal theory is on the metamotivational state within an individual and the reversals in behavior resulting from changes in state, most research studies use between individual analyses of dominant or typical state.
An attempt at understanding the coherencies within individuals rather than within variables has been a theme of the longitudinal studies done at Berkeley (Block 1971, Block & Robins 1993, Helson 1993, Helson & Roberts 1992, York & John 1992). These were ambitious studies when initiated, and have shown the costs, difficulties, and benefits of "studying personality the long way" (Block 1993). These longitudinal studies emphasize person centered as well as variable centered analyses and represent a powerful blend of psychometric and theoretical sophistication. For example, Block & Robins (1993) report that mean self esteem, indexed as the correlation between self and ideal self ratings, increases slightly for males and decreases slightly for females from ages14 to 23. Individual differences in self esteem are more consistent across this period for females than for males, and show different correlates of change across the two genders. Personality correlates of later drug use, political attitudes, or even subsequent parental divorce show strong and meaningful patterns that are not detectable in cross sectional analyses (Block 1993).
Whereas the Berkeley group focuses on the coherencies over time of individual life histories, others emphasize the autobiographical story of the self that makes up one's identity (McAdams 1990, 1993, Runyan 1990). McAdams suggests that the narrative tone of a life story is set by the quality of early experience and the forming of attachment. As children mature they are exposed to many different legends and myths as they develop their own life story and their conception of their self. Story scripts change with age and tend towards a concern with future generations. Studying the origins, characters, settings and scripts of a life story is said to provide "a framework for conceptualizing the development of the whole person, from birth to death." (McAdams 1990, p 192).
Based upon the mixed success of previous reviewers and prognosticators it is risky to make any strong predictions about the future. There are several themes, however, that have emerged in the past several years that offer both promises and challenges to the field of personality research.
As the rise of neuroscience and cognitive science threatens to split the discipline of psychology, so does the emphasis on biological mechanisms of individual differences and cognitive mechanisms of uniqueness threaten personality theory. There is an unfortunate tendency for the more biologically oriented to dismiss cognitive approaches as focusing on epiphenomena, and for cognitive theorists to ignore the advances in biological bases as irrelevant for understanding a person. There are far too few researchers emphasizing how cognitive interpretations can affect physiological state and in turn, how physiological structures and processes constrain and affect cognitive and affective reactions.
The past few years have seen a resurgence of interest in personality. Research spanning the range from genes to the lifespan, from the individual to the species, and from the normal to the pathological is being carried out in the name of personality theory. Once again, researchers and theorists from all parts of psychology are working on the fundamental questions of personality. What is integrating much of this work is an emphasis not just on description, but on the functions that personality serves. Evolutionary, biological, sociological, developmental, cognitive, and clinical approaches all provide unique perspectives to the field. What the next decade promises is an integration of these many separate foci.
Preparation of this chapter was supported in part by contract MDA903-93-K-0008 from the U.S. Army Research Institute to William Revelle and Kristen Anderson. The views, opinions, and findings contained in this chapter are those of the author and should not be construed as an official Department of the Army position, policy, or decision, unless so designated by other official documentation. I would like to thank K. J. Anderson, D. Billings, E. Gilboa, G. Rogers, S. Sutton, and the members of the Northwestern personality group for their helpful comments on parts of this manuscript.