This article is about the "four humours" in Greco-Roman medicine, a specific form of the more universal proto-medical concept of humourism. For the music by Hindemith choreographed by Balanchine, see The Four Temperaments. For the symphony by Carl Nielsen, see Symphony No. 2 (Nielsen).
The four temperament theory is a proto-psychological theory which suggests that there are four fundamental personality types: sanguine, choleric, melancholic, and phlegmatic.[2][3] Most formulations include the possibility of mixtures among the types where an individual's personality types overlap and they share two or more temperaments. Greek physician Hippocrates (c. 460 – c. 370 BC) described the four temperaments as part of the ancient medical concept of humourism, that four bodily fluids affect human personality traits and behaviours. Modern medical science does not define a fixed relationship between internal secretions and personality, although some psychological personality type systems use categories similar to the Greek temperaments.
^Woodcut from Johann Kaspar Lavater, Physiognomische Fragmente zur Beförderung der Menschenkenntnis und Menschenliebe (1775–1778)
^Merenda, P. F. (1987). "Toward a Four-Factor Theory of Temperament and/or Personality". Journal of Personality Assessment. 51 (3): 367–374. doi:10.1207/s15327752jpa5103_4. PMID16372840.