Look up the Stoned ape theory and watch some videos on google. All psychedelics as well as cannabis is included in this to me.
Terence McKenna - Wikipedia, the free encyclopedia
"In his book Food of the Gods,[21] McKenna proposed that the transformation from humans' early ancestors Homo erectus to the species Homo sapiens mainly had to do with the addition of the mushroom Psilocybe cubensis in its diet - an event which according to his theory took place in about 100,000 BC (this is when he believed that the species diverged from the Homo genus). He based his theory on the main effects, or alleged effects, produced by the mushroom. One of the effects that comes about from the ingestion of low doses, which agrees with one of scientist Roland Fischer's findings from the late 1960s-early 1970s,[22] is it significantly improves the visual acuity of humans - so theoretically, of other human-like mammals too. According to McKenna, this effect would have definitely proven to be of evolutionary advantage to humans' omnivorous hunter-gatherer ancestors that would have stumbled upon it "accidentally"; as it would make it easier for them to hunt.
In higher doses, McKenna claims, the mushroom acts as a sexual stimulator, which would make it even more beneficial evolutionarily, as it would result in more offspring. At even higher doses, the mushroom would have acted to "dissolve boundaries", which would have promoted community-bonding and group sexual activities-that would result in a mixing of genes and therefore greater genetic diversity. Generally McKenna believed that the periodic ingestion of the mushroom would have acted to dissolve the ego in humans before it ever got the chance to grow in destructive proportions. In this context, he likened the ego to a cancerous tumor that can grow uncontrollable and become destructive to its host. In his own words:
Wherever and whenever the ego function began to form, it was akin to a cancerous tumor or a blockage in the energy of the psyche. The use of psychedelic plants in a context of shamanic initiation dissolved-as it dissolves today-the knotted structure of the ego into undifferentiated feeling, what Eastern philosophy calls the Tao.
—Terence McKenna, Food of the Gods"