The stoned ape theory is a controversial theory first proposed by American ethnobotanist and mystic Terence McKenna in his 1992 book Food of the Gods.[1][2] The theory claims that the transition from Homo erectus to Homo sapiens and the cognitive revolution was caused by the addition of psilocybin mushrooms, specifically the mushroom Psilocybe cubensis, into the human diet[3] around 100,000 years ago. Using evidence largely based on studies from Roland L. Fischer et al. from the 1960s and 1970s, he attributed much of the mental strides made by humans during the cognitive revolution to the effects of psilocybin intake found by Fischer.
McKenna's argument has largely been ignored by the scientific community,[4] who cite numerous alleged discrepancies within his theory and claim that his conclusions were arrived at via a fundamental misunderstanding of Fischer's studies. McKenna's theory was not based on scientific evidence.[5]