Electrocutaneous input-output functions: Magnitude estimation and reaction time

An experiment was conducted on the effect of electrocutaneous stimuli on the generation of two types of input-output functions, and their relationship to each other. The data indicate that increasing electrocutaneous stimulus intensity results in a monotonic growth of magnitude estimation and a negatively decelerating decrease in reaction time. Reaction time approaches an asymptote at high intensities. The dynamic range of reaction time (RT), i.e., the RT which decreases as a function of increases in intensity was subtracted from the asymptotic reaction time (RT_min) for the subsequent analyses. The two-parameter power function provides a better fit for magnitude estimation as well as for RT - RT_min as a function of stimulus intensity than either a two-parameter linear or log-linear equation. When RT - RT_min is plotted as a function of magnitude estimation on a log-log scale, the data are within 4% of the predicted linear equation with a slope of -1, with no significant nonlinear components. If these data are plotted on a linear-linear scale, the linear coefficient is 31 % steeper than - 1, and a significant nonlinear component is present.