n. a theory of personality formulated in the 18th and 19th centuries by German physician Franz Josef Gall (1757–1828) and Austrian philosopher and anatomist Johann Kaspar Spurzheim (1776–1832). It stated that specific abilities or personality traits are represented by specific areas of the brain: The size of these brain areas determines the degree of the corresponding skill or trait. Proponents of the theory argued that the size of such locations could be indicated by bumps and hollows on the skull surface, based on the observation that the contours of the brain follow the skull contours. Although wrong in most respects, the theory suggested the idea of localization of function. Also called craniology. See also physiognomy. —phrenologicaladj.—phrenologistn.