"The relationship between brain structure and the Big Five personality traits is , meaning we do not know if they are responsible for personality, the result of personality, or the result of other unknown variables."

The correct answer is correlational

The Big Five was born from studies on the Theory of Personality Traits, representing a conceptual and empirical advance in this area, as it described basic human dimensions in a consistent and replicable way.

The Big Five model began to be structured in the early 1930s, when McDougall suggested analyzing personality from five independent factors that, at the time, were called intellect, character, temperament, disposition and humor.

At that same time, in Germany, Baumgarten suggested an analysis of language to understand personality traits. Baumgarten's work had a fundamental influence on Allport who, together with Odbert, examined about 400,000 words from Webster's New International Dictionaire, deriving 4,500 personality trait descriptors, a study that greatly influenced Cattell in his publications in the 1940s. publications by Cattell and Eysenck dominated the literature as the main models obtained through factor analysis.

In Baltimore (Maryland), Robert McCrae and Paul Costa, at the Gerontology research center at the National Institute of Health, started an extensive research program that identified the so-called five major factors: neuroticism, extraversion, openness to new experiences, sympathy and conscientiousness .