This is the 2007 version. Click here for the 2017 chapter 11 table of contents.

Summary: What is Personality?

Although Gordon Allport claimed to find 50 definitions of personality in his classic 1930s study, he identified three main approaches. Using simpler terminology than Allport, these three approaches are (1) sweeping, all-inclusive definitions (which Allport found useless), (2) the trait approach (which Allport later specialized in), and (3) the systems approach (where different levels or systems within human personality are identified).

Traits are durable characteristics of an individual. Types are collections of traits that define a category of human being. Type theories go back to the ancient Greeks. They reflect the customs and fashions of particular cultures and are likely to go out of date with time.

Raymond B. Cattell was known for his multivariate analysis of traits. He located 16 dimensions, 15 personality traits plus general intelligence, which could be measured with his 16-PF test. Cattell believed there were two larger-scale traits that dominated: extraversion/introversion and anxiety/non-anxiety. Eysenck came to similar conclusions, emphasizing extraversion/introversion and stability/instability.

Mischel shook up the world of personality research in 1968 with statements that seemed to challenge the existence of traits. Although Mischel said later (repeatedly) that he was only pointing to the importance of situational factors, his challenge stimulated a lot of research in the 1970s and 1980s to try to identify the most important personality traits, if any existed. The result was a convergence of many different investigators on the same list of five basic traits.

Thomas Bouchard did a unique study of identical twins who were separated at birth and raised in separate households. He found that IQ scores and standardized personality test results of the twins he studied were not very similar. However, in the realm of personal mannerisms, posture, sense of humor, and a variety of quirks and preferences, identical twins reared apart were often remarkably similar. This suggests that genetics may play a major role in shaping personality.

In the 1930s, personality tests such as the Rorschach and the MMPI became widely used. The MMPI was an attempt to develop a standardized, objective test that could be expanded in the future. The original MMPI had 10 clinical scales, diagnosing things like depression, and 3 validity scales for determining whether test-takers were lying or trying to fool the examiner. The MMPI became the most widely used psychological test, and over 400 new scales were developed for it. Because it consists entirely of True/False questions, the MMPI is easily administered and scored by computer.

Multiple personality is now called Dissociative Identity Disorder (DID). The diagnosis of DID became much more common after several widely-publicized cases, and some psychologists are skeptical of cases discovered in therapy, because (according to one theory) it can evolve out of expectations and leading questions in therapy itself. Despite this possibility, Dissociative Identity Disorder (DID) seems to be a genuine and distinctive disorder, with reported cases going back to the early 1800s.

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