• The model is based on Hans Eysenck's theory that personality is composed of traits, or factors, derived by the factor-analytic method.
• The theory uses statistical procedure to derive evidence of the factors of human personality.
• Robert McCrae and Paul Costa embarked on an extensive research program starting in the 1980s that identified five so-called robust or Big Five factors.

• These factors are neuroticism, extraversion, openness, agreeableness, and conscientiousness.
• More than 25 years and hundreds of studies later, one of the originators of the five-factor model accurately described it as marking “a turning point in the history of personality psychology” (McCrae, 2011, p. 210).

• The factors were confirmed through a variety of assessment techniques including self-ratings, objective tests, and observers’ reports.
  • McCrae and Costa then developed a personality test, the NEO Personality Inventory, using an acronym derived from the initials of the first three factors.

Four of the five factors show a stronger hereditary component: neuroticism, extraversion, openness, and conscientiousness. Agreeableness was found to have a stronger environmental component.

• The five factors have been consistently observed in Eastern as well as Western cultures, a finding that also supports a genetic component.
• McCrae and Costa noted that the Big Five factors and their traits appear to represent a “common human structure of personality” that transcends cultural differences.

• These five factors and their traits have been found in more than 50 diverse nations
• It is important to note that those countries tend to be urban, literate, well-educated societies.
• No evidence of the five factors was found in an extensive study of a small, isolated, largely illiterate tribal group residing in a remote area of Bolivia.

• There seem to be consistent sex differences in the five factors.
• Research carried out in 55 countries found that reported higher levels of neuroticism, extraversion, agreeableness, and conscientiousness than men.
• These differences were most pronounced in prosperous and egalitarian nations where women had greater opportunity for education and employment.

• The five factors have been found in children as well as adults. Longitudinal research studying the same people over a 6-year period demonstrated a high level of stability for all five traits.
• A large-scale research review showed that neuroticism, extraversion, and openness appeared to decrease as people reached their 60s, whereas agreeableness and conscientiousness seem to increase with age.

• Michael Ashton and Kibeom Lee have proposed a six-factor model of personality.
• Two of the factors—extraversion and conscientiousness—are similar to those found in the five-factor model; the other four differ in various degrees from the earlier work and are unique to this model of personality.
• Try the HEXACO personality test!

• The model was developed from several previous independent lexical studies.
• Language-based taxonomies for personality traits have been widely used as a method for developing personality models.
• This method, based on the logic of the lexical hypothesis, uses adjectives found in language that describe behaviours and tendencies among individuals.