Jitter and asynchrony discrimination are considered as special cases of the discrimination of temporal irregularities within auditory pulse trains. Variation in the number of nonjittered intervals permits spanning the range between the discrimination of a single temporal discontinuity (the asynchrony or gap test) and the discrimination of temporal modification to each interval (the jitter test). At high pulse frequencies, the discrimination of temporal irregularities is determined primarily by the number of jittered intervals. Jitter thresholds are approximately inversely proportional with the fourth root of the number of jittered intervals.