The bimodality of saccade duration during the exploration of visual scenes

ABSTRACT

Eye movement parameters are consistently investigated, and the distribution of these parameters are well known. Whereas saccade duration has been studied along with saccade amplitude , the distribution of saccade duration has not yet been reported. We aim to investigate the distribution of saccade duration in several eye movement datasets from the literature and from our own data to confirm the common, but never reported, observation that the distribution of saccade duration is bimodal. We consistently observed the bimodality of saccade durations, not task- or stimuli-dependent. We created two groups of saccades based on the saccade duration distribution. Our results suggest that short duration saccades could be partly linked to bottom-up processes and long duration saccades to top-down processes. This study highlights the importance of reporting the distribution of eye movement data, in addition to means, which do not allow a correct and representative analysis in the case of bimodal distributions.

KEYWORDS:

• Eye movement
• saccades
• bimodality
• top-down
• bottom-up

Acknowledgements

This work was supported by the ONR grant N00014-14-1-0670. We thank T. Adams, C. Bird, W. Carpenter, K. Corby, L. Hall, S. Martis and Y. Shi as well as S. Asante, B. Baker, A. Hobbs, K. Hubert, E. Krahn, J. Le, J. Leonard, R. Lundberg, K. Miller, A. Nye, A. Shah, N. Smith, L. Tunnicliff and S. Walworth for research assistance. We also thank William Carpenter for editing the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1 Wilming et al., Dryad https://doi.org/10.5061/dryad.9pf75 (2017).

2 More data for DS1 are available online: https://osf.io/48bkq/?view_only=78be244957834e7caaa7b69bb5187438.

3 Plots for the other conditions are shown online: https://osf.io/48bkq/?view_only=78be244957834e7caaa7b69bb5187438.

4 The model was downloaded from this website http://saliency.mit.edu/results_mit300.html.

Additional information

Funding

This work was supported by Office of Naval Research [grant number N00014-14-1-0670].