Evaluating a Model of Global Psychophysical Judgments: I. Behavioral Properties of Summations and Productions

The research presented is a partial empirical evaluation of the second author’s proposed psychophysical theory (Luce, 2002, 2003a,b). The theory deals with the global percept of subjective intensity in which there is a psychophysical function Ψ that maps pairs of physical intensities onto the positive real numbers and represents subjective summation and a form of ratio production. A number of behavioral properties have been shown to follow from these specific representations, and in the presence of structural conditions these properties are also sufficient for the representations. In four auditory experiments, key behavioral properties of summation over the two ears and a form of generalized ratio production are evaluated empirically. Despite a number of methodological issues, considerable support is found for particular forms of Ψ for summations and ratio productions separately. Steingrimsson and Luce (2003a) explore the behavioral properties that link summations and productions; Steingrimsson and Luce (2003b) addresses issues regarding the form of the psychophysical and weighting functions. 1This article is based, in part, on the first author’s Ph. D. dissertation (Steingrimsson, 2002).