Relation of loudness to intensity discrimination

Abstract

One outgrowth of our theory of intensity resolution is the following prediction concerning the relation of loudness matches to intensity discrimination: Two stimuli are matched in loudness if and only if their intensities divide their respective dynamic ranges proportionately in terms of number of JNDs [J. S. Lim, W. M. Rabinowitz, L. D. Braida, and N. I. Durlach, J. Acoust. Soc. Am. 62, 1256–1267 (1977)]. This prediction, which is essentially the same as that proposed by Riesz [R. R. Riesz, J. Acoust. Soc. Am. 5, 211–216 (1932)], is derived from our theory by assuming that loudness is the predominant cue used to discriminate intensity and that all stimuli are equally loud at the tops and bottoms of their dynamic ranges. This prediction is consistent with a wide variety of functions relating loudness to intensity (including the power law); all that is required is that loudness be a monotonically increasing function of the proportional JND factor and that this function be the same for all stimuli. This prediction does not, however, take account of the effects of context on loudness. In this paper, we discuss this prediction in detail and comment on its relation to other concepts concerning discrimination and loudness and on its consistency with experimental data. [Work supported by NIH and NSF.]