It might not even have to with traditional shamans, it could be simpler than that, from an article by a psychologist:
" I once was lucky enough to spend time in an Egyptian village in the late 1970s, before technology or even electric lights had arrived there. One of the villagers had long, impassioned conversations with people no one else could see. He also had a way of seeing through everyone’s pretensions. He could tell jokes no one else could get away with.
Village life was not utopia. It was difficult in many ways. But this one man, who would almost certainly be diagnosed with schizophrenia if he lived in the developed world, had a secure, safe place in his village. He could wander the wide-ranging mysteries his perceptions opened to him, and if he forgot to feed himself along the way, sooner or later someone would feed him and give him a gentle push toward the door of his home.
Contrast his life with that of a typical client in a mental-health agency in Seattle. I remember one man, early in my training, who gave me the most baffled, hurt look when he asked me, “Why do people on the radio lie to us?”
“I can tell that the woman who’s talking about Macy’s isn’t really happy,” he went on, “but she’s pretending to be happy. Why?”
He felt injured by the woman’s lies, and I could see why, because he had a point. He was accurately perceiving the incongruence in her voice. All of the lying we do to each other in the name of advertising can’t be good for us. But most of us, whose brains aren’t quite as strongly bathed in dopamine in certain places where my client’s brain was constantly overstimulated, can tune advertising out. He couldn’t. "
It's from a fascinating article: http://crosscut.com/2014/05/our-indiviualist-society-breeds-...