On Some Poststimulatory Effects at the Threshold of Audibility

Abstract

Poststimulatory threshold shifts were 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 using test stimuli of varying duration following the prime stimulus at various time intervals. The poststimulatory threshold shift depends little on the duration of the test stimulus, but it depends critically on the time interval between the termination of the prime stimulus and of the test stimulus. The poststimulatory threshold decreases as the time increases, increases with sensation level, and 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.