The Eysenck Personality Inventory (EPI), published in 1963, contains 48 questions and assesses two basic personality traits:
- Extraversion/Introversion: This scale measures how sociable and active or withdrawn and reserved a person is.
- Neuroticism/Stability: This scale measures the extent to which a person is prone to emotional instability and anxiety or is calm and balanced.
Using test scores from the Extraversion, Introversion, and Neuroticism scales, Eysenck identifies four personality types::
- Choleric
- Sanguine
- Phlegmatic
- Melancholic
G.V. Sukhodolsk believes that it is necessary to distinguish not four ("pure" types are an abstraction), but nine personality types – the norm and eight accentuations:
- Choleric – aggressive, irascible, changeable/impulsive.
- Choleric-Sanguine type – optimistic, active, extroverted, sociable, approachable.
- Sanguine – reliable, self-possessed, peaceful, judicious.
- Sanguine-Phlegmatic type – carefree, leading, stable, calm, poised.
- Phlegmatic – reliable, self-possessed, peaceful, judicious.
- Phlegmatic-melancholic type – diligent, passive, introvert, quiet, unsociable.
- Melancholic – reserved, pessimistic, sober, rigid.
- Melancholic-choleric type – conscientious, capricious, neurotic, resentful, restless.
- Normal type