It is a type of pseudoscience that studies the nodules on the human skull to determine the character, intelligence and personality of a person.
Phrenology, formulated at the end of the 18th century by Franz Joseph Gall, is a pseudoscience based on the study of the structure of the human skull to determine the character or mental abilities of man. Discredited scientific research, phrenology was in the United States up to the 1930s.
Bumpology is a less known name for phrenology. If you are interested in this topic, we invite you to read the more comprehensive entry under the phrase Phrenology.