So there was this fool named Terrence Mckenna. And by fool I mean one of the most linguistically gifted, psychedelically brave, fringe-creative, and enduring intellectuals I have came across. He's an idol. Anyways, amongst many theories he proposed in his short life, one is known as "The Stoned Ape Theory."
This is only going to be an introduction. To look at this with scientific scrutiny will require more effort than frankly I feel like asserting. His basic assertions are eloquent. They make intuitive sense. I see it more as a creative proposal to a still unanswered problem as oppose to a dissertation with a long and dry name that maybe nine people will ever read. He brought life and energy to science were most of his peers offered black boards and overhead projectors.
The setting is Northern Africa. An ice age has just ended causing global climate change. One of these changes effect our red-assed primitive ancestors. We go from tree swinging to flat plain waddling. As we try to find food in this new environment we see vegetation growing up under the shit piles of certain four legged beasts (1). Amongst other shrubbies, one of these plants are an ancestor of the magic mushroom. Yeah, you know were we're going.
We started nibbling on that shit. Here are where his three main assertions come into play. The first one is that at low level doses, much before any psychoactive effects takes place, there is an increase in visual acuity. As a barely evolved primate who has nibbled on the plants that spring forth from shit piles, I can confirm this phenomena. So applying some basic darwinian principles, we can see how this would benefit foragers.
The second principle is that at slightly higher doses, mushrooms will provide a substantial energy boost. Imagine an environment as stimulatingly dull as a grass plain...a boost in energy for a male ape is going to lead to erections (men will understand). That hairy, unbathed female thats been eyeing us since we brought the last shit-pile harvest isn't looking too bad. Basically, these apes eating the higher doses will be better food gathers and will have more offspring.
His third assertion is that at the really trippy levels, five grams or higher, a phenomnona known as glossolalia occurs. I've never experienced this but I'll take the shaman's word. This is basically is answer to the unanswered question. Were did language come from? How did our creativity spike so rapidly?
He proposed the apes who started eating a little, ate more because they could hunt better. They then began reproducing more frequently than the sober apes. As generations grew up on these plants, some arrogent bastards would eat too much and start shouting nonsense. It extrapolates from there.
Take nine minutes and hear it from the mans mouth. (Check out his hip wardrobe--trailblazer)
1) Ever wonder why ancient civilizations worshipped cows? Me too! Could it be because their shits seemed to produce these magical plants that allowed you to talk to God. mhmmm.
Some sources for you curious readers whom do not exist but I delude myself into believing in...