Copyright © 2007-2017 Russ Dewey
In the era before computers, traits and types were mostly a matter of speculation and opinion. Computers made it possible to use a more objective approach. Large numbers of traits could be analyzed to see which were most discriminative.
Traits can be represented by adjectives such as smart, ruthless, kind, or belligerent. More than 1,000 adjectives describe human personality traits. Which would account for the most variance in describing real human beings?
That language "account for the most variance" is important, because it points to the statistical procedures used to do the job. The procedures is simple, in principle: rate 1,000 personalities (or however many you have) on 1,000 traits (or however many you want to use).
Then analyze the results to see which traits are best at telling people apart. Those are the maximally discriminative traits. You can profile a person by rating them those traits, and the profile will distinguish between individuals with maximum efficiency.
Again: those will be the traits that tend to vary most between people. If everybody shares a trait (such as being human) then it tells you nothing about an individual and cannot be used to tell people apart.
If, on the other hand, people vary dramatically on some trait (like intelligence) then knowing how a person rates on that dimension will be informative. You will know more about the individual personality than you did before.
Raymond B. Cattell was an influential trait theorist in the post-World War II period. He wrote over 30 books and over 350 journal articles.
Cattell specialized in statistical analysis of personality traits. His method of choice was factor analysis.
Factor analysis is a multivariate approach, and it does just what we described above. It combs through data to find which factors "account for the most variance" in the data. The goal is to isolate variables (factors) that are as informative as possible.
An important asset of factor analysis is its objectivity. Unlike (for example) the creators of the authoritarian personality type, a factor analyst does not start out trying to prove a point. The goal is simply to find factors that best discriminate between different personalities.
How did Cattell arrive at his 16 traits? How did Cattell produce a personality profile?
Raymond B. Cattell
Cattell began with a list of over 4,000 words that described personality characteristics. Then he used factor analysis to locate 15 dimensions or factors that accounted for the most variance is descriptions of personality. Adding in general intelligence as a 16th factor, Cattell generated personality profiles using 16 traits.
Cattell did a further analysis of his data and found there were two dominant underlying dimensions: extraversion/
Cattell produced a standardized test, the 16-Personality Factor (16-PF) test, which could be used to rate individuals on the 16 factors. When the test is administered to groups of people from different occupations, group profiles may emerge.
For example, writers tend to be highly imaginative, while airline pilots are tough-minded. Creative artists are intelligent, sensitive, yet controlled.
How did the traits studied by Eysenck parallel those emphasized by Cattell?
Another prominent trait theorist of the 20th Century was Hans Eysenck. Like Cattell, Eysenck was extremely productive, publishing over 30 books, including Dimensions of Personality (1947), The Scientific Study of Personality (1952) and The Structure of Human Personality (1970). He also published well over 600 articles.
Eysenck emphasized two dimensions of personality: the extraversion/introversion dimension and the stable/unstable dimension. This echoed the findings of Cattell, because "stable/unstable" could well be another name for "anxious/non-anxious."
Goldberg (1993) reported an "electrifying burst of interest" in trait theories. The reason for the excitement was that many different research teams appeared to be zeroing in or converging upon the same group of five important traits as fundamental to human personality.
Digman (1990) described how different research teams made the same discovery. In each case, the research was done independently, using different methodologies, yet the researchers came up with the same basic list of characteristics.
What caused an "electrifying burst of interest"?
Here are the Big Five. Note the different names used for the same trait by various researchers in the years leading up to the big integrative insights around 1990.
Some of the labels are odd. People do not use the word "surgency" every day. It refers to the tendency of a people to put themselves forward, to surge outward in their activity.
Cattell called this trait "exvivia," a term he made up. Others would call it extraversion or activity level, the opposite of being shy or inhibited. The important thing is not the labels but the fact that researchers kept identifying the same dimensions as important for discriminating between individual personalities.
Goldberg (1992) developed a list of 100 adjective "markers" for the five traits. When you see these adjectives, you can tell whether a personality (in fiction or life) has one of the Big Five traits or not. Saucier (1994) pared the list down to the 40, as follows:
Traits are far from a complete description of a person. Traits are revealing because each represents a dimension along which people tend to differ.
The Big Five are simply the dimensions along which people tend to differ the most. The remarkable thing–as Goldberg, Digman, and others pointed out–was that different researchers came up with essentially the same factors.
How could you use the five traits to make a personality profile?
How could these five traits be used to describe a unique personality? You could rate the person on each of the five dimensions, using some standardized test or interview technique.
The result would be a profile: a list of 5 numbers describing (in rather skeletal fashion) the person's rating on each of the Big Five traits. To make the profile more complete, in a situation where it counted, one would add details unique to that person.
Digman, J. M. (1990). Personality structure: Emergence of the Five-factor Model. Annual Review of Psychology, 41, 417-440.
Goldberg, L. R. (1992) The development of markers for the Big-Five factor structure. Psychological Assessment, 4, 26-42.
Goldberg, L. R. (1993) The structure of phenotypic personality traits. American Psychologist, 48, 26-34.
Saucier, G. (1994) Mini-markers: A brief version of Goldberg's unipolar Big-Five markers. Journal of Personality Assessment, 63, 506-516.
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Copyright © 2007-2017 Russ Dewey