Frequency discrimination for tones of different levels but constant E/N0

Abstract

Wever's theory of pitch perception asserts that both place and periodicity mechanisms are used by the auditory nervous system, with periodicity predominant at low frequencies and place predominant at high. One way of gaining insight into the coexistence of the two mechanisms is to find an experimental parameter that, when varied, produces differential effects for low frequencies and high. To this end, signal level was varied and frequency discriminability was measured for tones of 500, 1000, and 4000 Hz. In order to examine the effects of level independent of E/N 0, the level of a noise masker was chosen so that the signal‐to‐noise ratio remained constant. Raising level was found to improve frequency resolution in the 500and 1000‐Hz conditions, while performance became worse in the 4000‐Hz condition. The high frequency data can be explained in terms of Henning's modified energy detector model, with the added assumption that filter width increases with level. The low‐frequency data are accounted for by a level‐dependent increase in the number of active channels in the counting model of Luce and Green.