Intensity discrimination as a function of frequency and sensation level

Abstract

Intensity discrimination was measured for pulsed sinusoids of various frequencies (200–8000 Hz) and sensation levels (5–80 dB). The data for all frequencies were fitted by a single function, ΔI/I=0.463 (I/I0)−0.072, where I0 is intensity at threshold, I is the intensity of the tone, and ΔI is the increment needed to obtain 71% correct in a two-interval forced-choice adaptive procedure. The form of this function is in good agreement with data reported in comparable studies but differs markedly from the data reported by Riesz [Phys. Rev. 31, 867–875 (1928)]. An analysis of the actual values of ΔI/I reported in the other studies indicates a range larger than would be predicted on the basis of individual differences among observers in this study. The data are also discussed differences among observers in this study. The data are also discussed in terms of the predictions of current theoretical models.