Detection and Relative Discrimination of Auditory “Jitter.”

Abstract

Thresholds for the minimal departure from periodicity and thresholds for discrimination of relative departure from periodicity were obtained in order to explore the limits of temporal resolution for auditory pulse trains. In a forced-choice test, listeners were presented pulse trains, one of which was subjected to more variability, or jitter, than the other three. The principal experimental variables examined were: the number of intervals; the mean interpulse interval; and, the jitter of the reference pulse train. Minimum thresholds for jitter, relative to the center interpulse interval, is less than 0.1% for a large number of pulses. Threshold jitter decreases with shorter interpulse intervals for a large number of pulses. Jitter thresholds are minimal for interpulse intervals of 4–6 msec for a small number of pulses. Jitter discrimination is approximately independent of the reference jitter for a small number of pulses and is nearly directly proportional to the reference jitter for a large number of pulses. The temporal precision of the auditory system, in contrast with its precision of spectral analysis, appears insufficient to account for minimal jitter thresholds.