Two empirical tests of informal predictions from Helson's adaptation-level theory.

Abstract

Two experiments on adaptation-level theory are reported which arise from informal predictions made by Helson (1964). They both involved interpolated anchors in comparative judgments, in order to avoid the sorts of response factors inherent in the category scaling technique normally employed in adaptation level studies. The first experiment indicated the operation of time error as interstimulus intervals are increased. The second showed that if the anchor stimulus is not judged it is less effective in producing contrast compared with when it is judged. In addition, response times and confidence ratings of judgments were shown to be potentially useful indices of differences in effectiveness among the various anchor stimulus levels used. The strong relationship between these two measures is discussed.