The role of a change heuristic in judgments of sound duration.

The present study investigated whether the quality of a frequency change within a sound (i.e., smooth vs. abrupt) would influence perception of its duration. In three experiments, participants were presented with two consecutive sounds on each of a series of trials, and their task was to judge whether the second sound was longer or shorter in duration than the first. In Experiment 1, participants were more likely to judge sounds consisting of a smooth and continuous change in frequency as longer in duration than sounds that maintained a constant frequency. In Experiment 2, the same bias was observed for sounds incorporating an abrupt change in frequency, but only when the frequency change was relatively small. The results of Experiment 3 suggested that the application of a change heuristic when generating duration judgments depends on the perception of change as originating from a single, integrated perceptual object.