In the early 1800's franz gall proposed his theory of phrenology, which is the study

It is the study of brain function. Phrenologists believed that different parts of the brain were responsible for different emotional and intellectual functions. Furthermore, they felt that these functions could be ascertained by measuring the bumps and indentations in your skull. That is, the shape of your skull revealed your character and talents. So using models and actual human subjects, phrenologists would study and map the shape of the head using specialized instruments.