Effect of spacing and range of stimuli on magnitude estimation judgements.

Abstract

This is an investigation of (a) the extent to which individual psychophysical functions are power functions, and (b) the effect of spacing and range of stimuli on the psychophysical function. The 6 experimental conditions consisted of 2 ranges and 5 spacings of the stimuli. A balanced Latin square design was followed, involving Os, conditions, and order of the session. In each session O judged the heaviness of each of 9 weights 20 times by the method of magnitude estimation. Individual psychophysical functions were found not to follow Stevens' law although averaging over Os does yield a power function. Stevens' power function thus seems to be an artifact of grouping. Significant differences emerged for the various conditions of spacing, but these differences cannot be unambiguously attributed to the effect of spacing, space-individual interaction, or the ordering of the sessions. (18 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved)