Pupil response hazard rates predict perceived gaze durations

Binetti, Nicola; Harrison, Charlotte; Mareschal, Isabelle; Johnston, Alan

Abstract

© 2017 The Author(s). We investigated the mechanisms for evaluating perceived gaze-shift duration. Timing relies on the accumulation of endogenous physiological signals. Here we focused on arousal, measured through pupil dilation, as a candidate timing signal. Participants timed gaze-shifts performed by face stimuli in a Standard/Probe comparison task. Pupil responses were binned according to "Longer/Shorter" judgements in trials where Standard and Probe were identical. This ensured that pupil responses reflected endogenous arousal fluctuations opposed to differences in stimulus content. We found that pupil hazard rates predicted the classification of sub-second intervals (steeper dilation = "Longer" classifications). This shows that the accumulation of endogenous arousal signals informs gaze-shift timing judgements. We also found that participants relied exclusively on the 2nd stimulus to perform the classification, providing insights into timing strategies under conditions of maximum uncertainty. We observed no dissociation in pupil responses when timing equivalent neutral spatial displacements, indicating that a stimulus-dependent timer exploits arousal to time gaze-shifts.

Citation

Binetti, N., Harrison, C., Mareschal, I., & Johnston, A. (2017). Pupil response hazard rates predict perceived gaze durations. Scientific Reports, 7, Article 3969. https://doi.org/10.1038/s41598-017-04249-9

• Journal Article Type: Article
• Acceptance Date: May 11, 2017
• Online Publication Date: Jun 21, 2017
• Publication Date: Dec 1, 2017
• Deposit Date: Jun 29, 2017
• Publicly Available Date: Jun 29, 2017
• Journal: Scientific Reports
• Electronic ISSN: 2045-2322
• Publisher: Nature Publishing Group
• Peer Reviewed: Peer Reviewed
• Volume: 7
• Article Number: 3969
• DOI: https://doi.org/10.1038/s41598-017-04249-9
• Public URL: https://nottingham-repository.worktribe.com/output/866956
• Publisher URL: https://www.nature.com/articles/s41598-017-04249-9