What type of analysis did Hans Eysenck use in developing his personality theory?

Hans Eysenck used factor analysis in developing his personality theory, which is central to his model of personality. Factor analysis is a statistical method that helps identify underlying variables, or factors, that explain the patterns of correlations among a set of observed variables. Eysenck employed this technique to determine the basic dimensions of personality that could effectively categorize individual differences.

Through factor analysis, Eysenck was able to distill a large number of personality traits into three fundamental dimensions: Extraversion, Neuroticism, and Psychoticism. This reduction allowed for a clearer understanding of how these traits interact to form a person's overall personality structure. Factor analysis is particularly effective in psychology because it provides empirical support for the classification of traits and helps psychologists examine the relationships between multiple variables simultaneously, leading to a more nuanced and structured conception of personality.