The Eysenck Personality Inventory (EPI), developed by Hans J. Eysenck in 1963, is a classic psychological questionnaire consisting of 48 items. It measures two fundamental dimensions of personality:
- Extraversion vs. Introversion: the degree to which someone is sociable, energetic, and outgoing versus reserved and quiet.
- Neuroticism vs. Stability: the tendency toward emotional instability and anxiety versus calmness and balance.
Based on these dimensions, Eysenck identified four personality types commonly used in psychology:
- Choleric
- Sanguine
- Phlegmatic
- Melancholic
Later, H.V. Sukhodolsky proposed a more detailed classification, suggesting nine personality types – the normal type plus eight accentuations, which better reflect real-life diversity:
- Choleric – aggressive, quick-tempered, impulsive.
- Choleric-sanguine – optimistic, active, extraverted, sociable, approachable.
- Sanguine – talkative, lively, easygoing.
- Sanguine-phlegmatic – stable, calm, balanced, carefree.
- Phlegmatic – reliable, self-controlled, peaceful.
- Phlegmatic-melancholic – diligent, introverted, quiet, withdrawn.
- Melancholic – reserved, pessimistic, rigid.
- Melancholic-choleric – conscientious, moody, touchy, restless.
- Normal type