This pseudoscience, led by Franz Joseph Gall, becomes increasingly used to advance claims of both racial hierarchy and racial equality. Many resources and much time are spent studying human skulls, with completely contradictory findings. At the same time, the "debate" further entrenches the idea that racial differences have significant biological roots.

"Some of his [Gall's] earlier studies were made among inmates of jails and lunatic asylums, and some of the traits that he presumed to detect were criminal. These he named after their excessive manifestations, mapping out organs of murder, theft, and so on. However, the names were changed to align with more moral and religious considerations" (Britannica, n.d.).