Interpreting measures of frequency selectivity: is forward masking special?
In a previous article [Lutfi, J. Acoust. Soc. Am. 76, 1045-1050 (1984)], the following relation was used to predict measures of frequency selectivity obtained in forward masking from measures obtained in simultaneous masking: F(g) = G + H(g) - H(0), where, for a given masker level, F is the amount of forward masking (in dB) as a function of signal-masker frequency separation (g), H is the amount of simultaneous masking, and G is the amount of forward masking for g = 0. In the present study, the relation was tested for a wider range of signal and masker frequencies, masker levels, and signal delays. The relation described thresholds from all conditions well with the inclusion of one free parameter lambda corresponding to a constant frequency increment, F(g) = G + H(g + lambda) - H(lambda). The parameter lambda was required to account for observed shifts in the frequency of maximum forward masking. It is argued that a single tuning mechanism can account for commonly observed differences between simultaneous- and forward-masked measures of frequency selectivity.
Lutfi
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Waisman Center, University of Wisconsin, Madison 53705.
D000328:Adult; D001309:Auditory Threshold; D006801:Humans; D010470:Perceptual Masking