The role of a change heuristic in judgments of sound intensity

Leboe and Mondor (2008) demonstrated that participants will apply a change heuristic when making duration judgments. In this study we investigated whether participants would apply this same change heuristic when making judgments about the perceived intensity of a sound. In two 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 louder or quieter than the first. In Experiment 1, participants were more likely to judge sounds that increased in frequency as louder in intensity than sounds that maintained a constant frequency. In Experiment 2, participants were more likely to judge sounds that either increased or decreased in frequency as louder in intensity than sounds that maintained a constant frequency. We interpret these results as evidence that reliance on a change heuristic leads to the illusion of increased intensity.