Perceived duration of auditory oddballs: test of a novel pitch-window hypothesis.

Abstract

Unexpected oddball stimuli embedded within a series of otherwise identical standard stimuli tend to be overestimated in duration. The present study tested a pitch-window explanation of the auditory oddball effect on perceived duration in two experiments. For both experiments, participants listened to isochronous sequences consisting of a series of 400Hz fixed-duration standard tones with an embedded oddball tone that differed in pitch and judged whether the variable-duration oddball was shorter or longer than the standard. Participants were randomly assigned to either a wide or narrow pitch-window condition, in which an anchor oddball was presented with high likelihood at either a far pitch (850Hz) or a near pitch (550Hz), respectively. In both pitch-window conditions, probe oddballs were presented with low likelihood at pitches that were either within or outside the frequency range established by the standard and anchor tones. Identical 700Hz probe oddballs were perceived to be shorter in duration in the wide pitch-window condition than in the narrow pitch-window condition (Experiments 1 and 2), even when matching the overall frequency range of oddballs across conditions (Experiment 2). Results support the proposed pitch-window hypothesis, but are inconsistent with both enhanced processing and predictive coding accounts of the oddball effect.