FACTOR ANALYSIS AND THE SEARCH FOR THE STRUCTURE
OF PERSONALITY
Alongside Allport and Murray, we find another pioneer of the trait approach,
Raymond Cattell. Unlike many theorists, Cattell did not begin with insightful
notions about the elements that make up human personality. Rather, he
borrowed an approach taken by other sciences. Notably, Cattell ’s first college
degree was in chemistry. Cattell argued that just as chemists did not begin by
guessing what chemical elements must exist, psychologists should not begin
with a preconceived list of personality traits.
Much of Cattell ’s work was devoted to discovering just how many basic
personality traits there are. Psychologists have identified, measured, and re-searched hundreds of traits. But certainly many of these traits are related.For example, being sociable is not entirely different from being extraverted,
although we can point to some fine distinctions. In his quest to discover the
structure of human personality, Cattell employed a statistical technique calledfactor analysis. Although a complete understanding of the procedure is be-
yond the scope of this book, an example can illustrate how factor analysis is
used to determine the number of basic personality traits.
Suppose you had tests to measure the following 10 traits: aspiration, com-
passion, cooperativeness, determination, endurance, friendliness, kindliness,persistence, productivity, and tenderness. You could give these tests to a group
of people and obtain 10 scores per person. You might then use correlation
coefficients (Chapter 2) to examine how scores on one test compare with scores
on the other nine tests. For example, you might find that friendliness and ten-
derness scores are highly correlated. If a person scores high on one test, you
can predict with some confidence that the person also will score high on the
other test. Looking at the pattern of correlation coefficients, you might discover
that the tests tend to cluster into two groups. That is, five of the tests are highly
correlated with one another, but not with the other five tests. These other five
tests are similarly correlated among themselves, but not with the tests in the
first group. The two groups might look something like this:
Group A Group B
aspiration
compassion
determination cooperativeness
endurance friendlinesspersistence kindliness
productivity tenderness
Although you originally measured 10 traits, a reasonable conclusion
would
be that you actually measured two larger personality dimensions, one
having to do with achievement and the other with interpersonal warmth.
This is a simple illustration of Cattell ’s basic approach. By analyzing data
from various sources with factor analyses, he attempted to determine how
many of these basic elements exist. He called the basic traits that make up
the human personality source traits .158 CHAPTER 7 The Trait Approach