If you think that the shape of a person's head can tell you everything you need to know about him, you believe in phrenology, or the study of skulls.
Phrenology is outdated today, but it was a popular area of study in the nineteenth century. It was considered a "pseudoscience," or false science, even at the time, yet phrenology was taken seriously by some psychiatrists and neurologists, who would feel a patient's head for bumps they believed revealed aspects of personality, character, and health. The literal Greek meaning of phrenology is "mental science," from the root word phrenos, or "mind."