Psychologist hans eysenck used factor analysis to identify patterns of traits and found that personality could best be described in terms of just three major dimensions.

Hans Eysenck focused on the relationship between two major personality dimensions:

Introversion and Extroversion

He used these dimensions to organize personality traits in a range of emotionally unstable to emotionally stable. For example the trait "impulsive" would be considered extroverted and emotionally unstable.