As some of you know, one of my abiding research interests is the relationship between pain and self-control. Thus I bring you this:
A scientist developing a prosthetic pain detection system to help lepers who had lost sensation in their limbs avoid damage describes its failure:
In the end we had to abandon the entire scheme. Most important, we found no way around the fundamental weakness in our system: it remained under the patient's control. If the patient did not want to heed the warnings from our sensors, he could always find a way to bypass the whole system. Why must pain be unpleasant? Why must pain persist? Our system failed for the precise reason that we could not effective duplicate those two qualities of pain. They mysterious power of the human brain can force a person to STOP! --something I could never accomplish with my substitute system. And 'natural' pain will persist as long as danger threatens, whether we want it to or not, unlike my substitute system, it cannot be switched off."
Brand, P. and P. Yancey. 1993. Pain: The Gift Nobody Wants. New York: Harper Collins. Pp.195-186