Hans Eysenck
SchoolBiological Trait Theory
Lived1916 – 1997
FromGermany / UK
Biological Trait Theory

Hans Eysenck

Temperament written in biology

A trait theorist who rooted personality in the workings of the nervous system.

Personality is determined to a large extent by a person's genes.
— Hans Eysenck

Who they were

Hans Eysenck argued that personality rests on a biological foundation, proposing a small set of broad dimensions such as extraversion and neuroticism tied to differences in arousal and temperament. He prized measurement and prediction, and was famously willing to provoke debate within his field. His dimensional model became one of the most influential and widely tested frameworks in the study of personality. It laid groundwork for later biologically grounded theories of who we are.

Famous books

What they left on the shelf

Their big idea

Biological Trait Theory

Hans Eysenck argued that personality rests on a few broad, measurable dimensions rooted in biology, with traits like extraversion tied to differences in how easily the nervous system is aroused. In his view, the quiet and the outgoing differ not by upbringing alone but by the baseline excitability they are born with.

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Eysenck — What they’d ask you

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