On Some Poststimulatory Effects at the Threshold of Audibility

Abstract

Poststimulatory threshold shift has been measured for 1000-cps stimuli of varying duration and sensation level, turned on and off either without audible transients or abruptly. The measurement was performed by means of test stimuli of varying duration and following the prime stimulus at various time intervals. The results show that the poststimulatory threshold shift depends little on the duration of the test stimulus, but that it depends critically on the time interval between the termination of the prime stimulus and of the test stimulus. The poststimulatory threshold decreases as this time increases. The poststimulatory threshold increases with sensation level and it depends in a complex fashion on the duration of the prime stimulus. The time pattern of the threshold changes radically when a gradual cutoff of the prime stimulus is replaced by an abrupt one. Replacing the 1000-cps tone by a random noise leads to the same result as an abrupt cutoff.

Short-term spectral effects in pure-tone forward masking

“…However, since the interval from masker offset to probe offset is greater for the cos than for the cos •' condition ( Fig. 2), masking should be less for cos (Zwislocki, Pirodda, and Rubin, 1959), in contrast to what is observed. Also, changing the masker-probe interval seems to have little or no effect on the highfrequency side of psychophysical tuning curves, the major effect being on the low-frequency slope (Rodenburg, Verschuure, and Brocaar, 1977).…”

Interactions of masker bandwidth with signal duration and delay in forward masking

“…Several previous workers have argued that the most important part of the signal in determining threshold in forward masking is the offset (Zwislocki et al, 1959: Gardner, 1947Munson and Gardner, 1950;Luscher and Zwislocki, 1949;Elliot, 1962). Thus if offset-offset time is constant, threshold should be essentially independent of duration.…”

Effects of masker component phase on the forward masking produced by complex tones in normally hearing and hearing-impaired subjects

“…Previous research using sinusoidal forward maskers (with signal frequency equal to masker frequency) has shown that the slopes of growth-of-masking functions for normally hearing subjects are often less than 1 (Jesteadt et al, 1982;Munson and Gardner, 1950;Widin and Viemeister, 1979;Zwislocki et al, 1959). It has been proposed that slopes less than 1 occur when the masker level falls in a range where the basilar-membrane response is highly compressive and the signal level falls in a range where the response is more nearly linear (Moore, 2003;Moore and Oxenham, 1998;Oxenham and Moore, 1995;Plack and Oxenham, 1998).…”