phrenology pseudoscientific practice phrenology, the study of the conformation of the skull as indicative of mental faculties and traits of character, especially according to the hypotheses of Franz Joseph Gall (1758–1828), a German doctor, and such 19th-century adherents as Johann Kaspar Spurzheim (1776–1832) and George Combe (1788–1858). Phrenology enjoyed great popular appeal well into the 20th century but has been wholly discredited by scientific research.