Surprise leads to noisier perceptual decisions

Abstract

Surprising events in the environment can impair task performance. This might be due to complete distraction, leading to lapses during which performance is reduced to guessing. Alternatively, unpredictability might cause a graded withdrawal of perceptual resources from the task at hand and thereby reduce sensitivity. Here we attempt to distinguish between these two mechanisms. Listeners performed a novel auditory pitch-duration discrimination, where stimulus loudness changed occasionally and incidentally to the task. Responses were slower and less accurate in the surprising condition, where loudness changed unpredictably, than in the predictable condition, where the loudness was held constant..