Source: Astral Codex Ten
by Scott Alexander
“A friend asked me to investigate the following mystery: why do 5-10% of skulls from 10,000 BC to 3,000 BC, all over the world, have holes in them? Why do bone growth patterns indicate that most skull-hole-havers survived years after their holes were drilled, even though brain surgery today requires careful sterilization (and frequently, prophylactic antibiotics) to prevent fatal infections? And why did everyone stop doing this sometime around the beginning of recorded history? Was it cultural diffusion? No. Trepanation (the technical term for drilling a hole in the skull) was common across Europe and South America, with scattered cases in Africa and other continents. The Old and New Worlds had limited contact after about 10,000 BC, and most customs don’t survive for five thousand plus years with no reason.” (10/21/26)