In Food of the Gods, Terence McKenna presents his monkey theory about trance. In this theory, he explains that magic mushrooms containing the psychoactive psilocybin may have played an important role in the evolution and transformation of the first human species (Homo erectus) into modern humans (Homo sapiens) and the creation of his language and culture. . He says in his book that after coming down from the tree, the first man began to experiment and consume new types of food available in nature and introduced psychedelic mushrooms into his food chain. Consuming a small amount of these mushrooms can cause sexual stimulation, increase visual accuracy (and as a result better hunting and camouflage) and by creating audible sensations and images, it can be a spark for the invention of language by humans.