Pain Is in the Ear of the Beholder

When it comes to pain, what you hear is what you get. That’s the conclusion of a recent study that trained subjects to associate specific sounds with specific degrees of pain, then switched the sounds in mid-experiment. Subjects who received increased pain with sounds that had previously indicated reduced pain experienced as much pain relief as those who had been given morphine in another series of experiments. The study, reported in Science News and conducted by neuroscientist Robert C. Coghill of Wake Forest University School of Medicine in Winston-Salem, N.C., fitted ten volunteers to a device that delivered heat pulses to their lower right legs.The volunteers were taught to expect  one of three intensities of painful heat, depending on a tone that was sounded before the pain was administered. Once the subjects were trained, researchers switched the
signals in one third of the tests so that volunteers received heat
pulses that were either of higher or lower intensity than they expected. When participants received the most-painful heat after expecting only
moderately painful jolts, the intensity of their self-reported pain
fell by 28 percent compared with trials in which they both expected and
experienced the severe pain. Read more.