I am a bit of a fan of the theory, it makes sense that our early primate ancestors would have come across psychedelic mushrooms as they foraged for food. I think the theory is pointing toward the rapid growth in the human brain size over a considerably short time span and the development of consciousness and abstract thought. For me, mushrooms seem like a likely catalyst to project human evolution so rapidly. The benefits in regards to the efficiency of hunting after ingesting low doses are pretty well noted. Any benefit that aids in the survival of a genetic line only re-enforces the beneficial behaviour (mushroom use). Maybe the development of our brain capacities was just a side affect to our early ancestors sharpening up there awareness prior to hunting? Who knows?