Temporal relations in profile comparisons

Abstract

In these experiments, the standard alone consists of 21 equal‐amplitude components spaced at equal log‐frequency intervals between 200 to 5000 Hz, presented for 500 ms. The listener's task is to discriminate whether the 1000‐Hz (signal) component is at the same level as the 20 other components or slightly higher in level. Absolute level of the signal component is not a reliable cue because the overall level of the tones is chosen randomly on each presentation. The results show that the listener is very sensitive to the relative difference in the temporal onset of signal and standard. The threshold for an increment is smallest when the onsets are the same, but increases 15–20 dB if the signal component begins 50 ms before the onset of the standard. The results imply that the internal representation of intensity level is not a static quantity but a process having considerable dynamics. Unless the starting times in relevant channels are nearly the same, the channels are not coherent, and any cross‐channel co...