Resetting the pitch-analysis system. 2. Role of sudden onsets and offsets in the perception of individual components in a cluster of overlapping tones.

Experiments on young adults studied the effects of suddenness of onset or offset on the discrimination of the order of pitches of individual tones in a 1-s, 4-tone cluster of overlapping pure tones. In experiment 1, the tones, all within a critical band, went on asynchronously. Each rose and decayed linearly in amplitude. Faster onsets, within the range 10 to 640 ms as measured on the first tone, increased the accuracy of the discrimination of the order of onsets, but 10-ms onsets were slightly worse than 40-ms onsets in early sessions. Experiment 2 found similar effects for the abruptness of offsets of tones in clusters whose components came on synchronously but went off asynchronously. Onset order was very much easier to detect than offset order. The auditory system may use neural onset and offset responses to reset itself and carry out new analyses at frequency-by-amplitude points of sudden amplitude change, thereby contributing to auditory scene analysis.