To me this is very interesting, why is it that we find this? Some scientists argue that this is because of the lineage of people's whom have come in to N&S America being that of people's deep in shamanistic traditions. And that they then would be much better able to seek out and find these psychoactive plants. And this is obviously very true, the shamanic tendencies of these people can be traced back in to asia, to areas such as Mongolia and Tibet from which they came, where today even these traditions are very strong. But this doesn't hold up so strongly as a complete picture, when we look to the fact that simply looking will not nessisarily turn up these plants if they're not there. Every tribal community ever studied has had a means of altering their consciousness, be it through psychoactive plants, or fermentation or even putting the body through ordeal to excite trance states. These seem to be universal aspects of humanity, and psychoactive plants tend to be the first choice of people's when they're available in their environments. Because when they are not, tribal people will go to great lengths to achieve altered states or communion with the spirit world. They sometimes fast for weeks alone in the wild, sometimes they hyperventilate through controlled breathing techniques, but most commonly they will spin in a circle for hours and the vertigo alters their consciousness such that they can summon spirit. So we know that tribal people the world over have actively been in the pursuit of these plants and states, so why is it that we find the overwhelming amount of them in North & Sourh America?
Perhaps it is the ecosystems that reside there, perhaps as lineages of plants evolved psychoactive properties they had some survival advantage for these unique ecosystems? But when we ask the shamans themselves they say that the plants are teachers and that they've come to help humanity grow. So perhaps North and South American people's were simply the most able to listen?