Why would anyone need a hole in the head? Archaeologists have unearthed human skeletons from the Stone Age with egg-sized cavities in the skull. One interpretation of these holes is that our prehistoric ancestors believed abnormal behavior was caused by the inhabitation of evil spirits. These holes might be the result of trephination —drilling the skull to provide an outlet for those irascible spirits. Fresh bone growth indicates that some people did survive this “medical procedure.”
Just the threat of trephining may have persuaded some people to comply with tribal norms. Because no written accounts of the purpose of trephination exist, other explanations are possible. For instance, perhaps trephination was simply a form of surgery to remove shattered pieces of bone or blood clots that resulted from head injuries ( Maher & Maher, 1985 ).
The notion of supernatural causes of abnormal behavior, or demonology, was prominent in Western society until the Age of Enlightenment. The ancients explained nature in terms of the actions of the gods: The Babylonians believed the movements of the stars and the planets expressed the adventures and conflicts of the gods, and the Greeks believed that the gods toyed with humans, that they unleashed havoc on disrespectful or arrogant humans and clouded their minds with madness.