Interoceptive awareness selectively predicts timing accuracy in irregular contexts.

Awareness of psychophysiological changes has been proposed to play a role in duration perception; however, evidence on whether interoceptive awareness affects timing is mixed, and it is not clear which task features favor the reliance on bodily changes to track time. Here we tested the hypothesis that interoceptive awareness is selectively involved in timing when the context does not provide reliable cues on elapsed time. We developed a novel paradigm assessing interval reproduction in two conditions: 1) with regularly spaced stimuli during the encoding/reproduction phase (regular condition), 2) with irregularly spaced stimuli during the encoding/reproduction phase (irregular condition). Interoceptive awareness was assessed using the "Self-Awareness Questionnaire", investigating the frequency of common bodily sensations. Interoceptive awareness predicted timing accuracy in the irregular, but not in the regular condition; also, the contribution was specifically due to awareness of visceral sensations rather than somatosensory sensations. Overall, results suggest that individual differences in interoception differently affect timing according to contextual features, consistently with evidence that different mechanisms mediate timing in different conditions.