It so happens that this particular group of  researchers have shown that sensations of pain--actually, you  can generate pain psychologically, and it would be as real; there's  absolutely nothing physical to cause you pain, but you can actually create a lot of pain in people by suggesting it to them, and you can  reduce pain by suggesting to them all kinds of things that have  nothing to do with what's happening in reality, and the perception  of pain would decrease. 