Toby and Cosmides (1990) argue that sex produces a reshuffling of genes in
each generation, making it highly unlikely that a single, unified set of genes
related to personality type would be passed from one generation to the next.
Many prefer to measure the degree to which an individual expresses a
personality trait—an enduring personal characteristic that reveals itself in a
particular pattern of behaviour in different situations.
Personality traits are not simply patterns of behaviour: they are factors that
underlie these patterns and are responsible for them. Once our personality traits
are developed, they reside in our brains but can be changed. Thus, we carry our
personality traits around with us in our brains.
Identification of Personality Traits
Ultimate goal of the personality psychologists is to explain what determines
Allport’s Search for Traits
Gordon Allport was one of the first psychologists to search systematically for a basic
core of personality traits; began by identifying all words that described aspects of
personality, analyzed and identified those words that describe only stable personality
characteristics. Why? He believed that extent to which trait labels appear in English
attests to the importance of traits in how people think about themselves and others. He
also believed that people with a particular trait react similarly across situations because
they experience a unique sense of similarity across those situations that guide their
feelings, thoughts and behaviour.
According to Allport, not all traits have equal influences. The most powerful are cardinal
traits which characterize a strong unifying influence on a person’s behaviour (rare) and
these kinds of people stood out in a crowd. Central traits are less singular in influence
but capture important characteristics in an individual (e.g. saying someone is warm and
honest in order to distinguish them from others). Secondary traits include characteristics
that have minor influence on the consistency of behaviour (e.g. a person’s tendency to
frequently change jobs).
Cattell: Sixteen Personality Factors
Raymond Cattell used Allport’s list of trait words for this theory of central traits and
shortened the list down to 171 adjectives he believed made up a relatively complete set
of distinct surface traits (observable behaviours). He used factor analysis to identify
clusters that he believed represented underlying traits and eventually identified 16
personality factors and referred to them as source traits since they were the foundations
on which personality developed (Fig. 14.3).