Psychology? It's all in the mind.
In the psychological study of personality, an individual's characteristic or habitual inclination or mode of emotional response. The notion of temperament in this sense originated with Galen, who developed it from an earlier theory regarding the four humours: blood, phlegm, and black and yellow bile. The subject was taken up in the 20th century by Ernst Kretschmer and later theorists, including Margaret Mead. Today researchers emphasize physiological processes (including the endocrine and autonomic nervous systems) and culture and learning.
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