Responses by humans to painful electric shocks are significantly modified at subjective, behavioral, and physiological levels by verbal manipulations of degree of choice and justification for further exposure to the aversive stimuli. Pain perception, learning, and galvanic skin resistance are altered under these conditions of “cognitive dissonance,” as they are by reductions in voltage intensity.
Zimbardo, P. G., Cohen, A. R., Weisenberg, M., Dworkin, L., & Firestone, I. (1966). Control of pain motivation by cognitive dissonance. Science, 151(3707), 217-219.
10.1126/science.151.3707.217