Optimists are no longer alone in promoting “mind over matter.” A compelling study claims there is chemical credence for the placebo effect, at least in masking pain.
University of Michigan at Ann Arbor neuroscientist Jon-Kar Zubieta, who led the work, says that people produce a natural painkilling chemical in the brain when they expect to experience relief. Researchers gave test subjects a slow, long, harmless injection of a pain-inducing salt solution into the jaw. When the injection began, the subjects were asked to rate their level of pain. As it continued, the researchers said, falsely, that they had just added pain-relieving serum into the solution. Subjects were asked again to rank their discomfort.