Paired comparison scaling of reaction potential in two different experiments on habituation

Thurstone’s method of paired comparisons was employed to obtain scaled values of reaction potential from two completely different experimental situations involving response decrement. The first was one in which the GSR was measured on 10 repeated presentations of a visual stimulus (N= 89). The second involved 80 presentations of ordinary visual scenes; the S looked at each scene as long as he wished before switching to the next (i.e., looking time was measured. N=80). Scaling reaction potential by Thurstone’s method provided a common operational definition for both sets of data and permitted their direct comparison in identical units. Both measures showed substantial decrement in reaction potential across stages, with the GSR scale values dropping steeply from the first to the second trial and. thereafter, following a course of decline similar to the looking time scale values. Tlie correlation of the two sets of scale values was essentially linear and equalled 0.90.