Phrenology
Phrenology is the study of how the human cranium's (skull's) shape and size determine personality, behavior and mental abilities. Phrenologists argue that the brain is the organ representing the human mind, and that the functioning of the mind- and consequently behavior- is determined by brain size and its components. Phrenology as a perspective was developed in the late 1700s. While it was a previously popular theory in psychology, it is now considered outdated.