If we sincerely believe that our index finger is five times bigger than it really is, our sense of touch improves. Researchers demonstrated that this is the case in an experiment in which the participants were put under professional hypnosis. When the participants signaled that they understood the opposite hypnotic suggestion that their index finger was five times smaller than it actually was, their sense of touch deteriorated accordingly. The study shows that our tactile perception is affected and can be altered by our mental processes.