The idea of brain localization led to phrenology, which was advocated by German physician Franz Joseph Gall in the late 18th century. Phrenology was very popular in the 19th century, influencing neurobiology and psychiatry.
The idea behind phrenology was that the brain is the organ of the mind, and that certain brain areas have specialized functions. In a word: localization.
Phrenologists believed that certain brain areas developed proportionally to a person’s propensities. Further, the cranial bone conformed to accommodate these different brain areas, with their corresponding character traits. As such, getting a sense of a person’s capacity for a given personality trait could be had by simply measuring the relative area of the cranium overlying a particular brain part.
The simple form of phrenology was feeling for bumps on the head. Phrenologists charted such personality attributes as caution, combativeness, hope, wit, and self-esteem to areas of the skull.
While mainstream academia was skeptical of phrenology from the get-go, phrenological inability to be a predictive indicator led to its dismissal as a pseudoscience in the early 20th century. One of the later-day proponents of phrenology was the Belgium Catholic priest Paul Bouts. But then, Christians ipso facto have shown themselves as gullible.