The detectability, discriminability, and perceived magnitude of painful electrical shock.

Thresholds for sensation, pain, and tolerance were obtained from 20 male and 20 female observers who received trains of electrical pulses applied to the volar forearm. Also determined were estimates of sensory magnitude for a series of stimuli that spanned the pain sensitivity range (PSR) between pain threshold and tolerance, as well as Weber fractions for the discrimination of stimuli at the midpoint of the PSR. There were great individual differences in all dependent variables. Females had significantly lower values for all thresholds but did not differ from males in the growth of sensory magnitude or in discriminatory capacity. Power functions, with a median exponent of 1.74 and a mean of 2.39, fit the scaling data well. The results are analyzed for a suggested negative correlation between exponent and stimulus range. The presence of such an effect indicates that electrocutaneous stimulation provides a powerful technique for the analysis of individual differences and the evaluation of psychophysical theories.