Common stimulus effects on the Weber and loudness growth functions

Abstract

The relationship between the Weber function and the loudness growth function is an ongoing and controversial theme in the literature. Although the effect of stimulus differences on the Weber function is well known, no work has exploited these stimulus differences in an effort to demonstrate a relationship between intensity discrimination and loudness scaling. Three listeners performed intensity discrimination using white noise, and using bandlimited tone complexes centered at 0.25 and 3 kHz. An adaptive gated pedestal method was employed. As expected, Weber’s law obtained for intensity discrimination of white noise, whereas the ‘‘near miss’’ obtained for the bandlimited stimuli. The listeners then performed loudness scaling using category rating with the same set of stimuli. Strong linearity was observed in the loudness functions for white noise, whereas nonlinearity was observed in the functions for the bandlimited stimuli. Results are consistent with the multiband excitation model proposed by Florentine etal. [J. Acoust. Soc. Am. 81, 1528–1541 (1988)], which explains the common stimuli effects by differences in excitation patterns. These data therefore show that there is a relationship between the Weber and loudness growth functions.