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 Margaret Mead . Today researchers emphasize physiological processes (including the endocrine and autonomic {{link=nervous system">nervous system s) and culture and learning .