The role of eye movements in a contour detection task

Van Humbeeck, Nathalie and Schmitt, Nadine and Hermens, Frouke and Wagemans, Johan and Ernst, Udo A. (2013) The role of eye movements in a contour detection task. Journal of vision, 13 (14). ISSN 1534-7362

Full content URL: http://www.journalofvision.org/content/13/14/5.ful...

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The role of eye movements in a contour detection task

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Abstract

Vision combines local feature integration with active viewing processes, such as eye movements, to perceive complex visual scenes. However, it is still unclear how these processes interact and support each other. Here, we investigated how the dynamics of saccadic eye movements interact with contour integration, focusing on situations in which contours are difficult to find or even absent. We recorded observers' eye movements while they searched for a contour embedded in a background of randomly oriented elements. Task difficulty was manipulated by varying the contour's path angle. An association field model of contour integration was employed to predict potential saccade targets by identifying stimulus locations with high contour salience. We found that the number and duration of fixations increased with the increasing path angle of the contour. In addition, fixation duration increased over the course of a trial, and the time course of saccade amplitude depended on the percept of observers. Model fitting revealed that saccades fully compensate for the reduced saliency of peripheral contour targets. Importantly, our model predicted fixation locations to a considerable degree, indicating that observers fixated collinear elements. These results show that contour integration actively guides eye movements and determines their spatial and temporal parameters.

Keywords:eye movements, Contour integration, Fixation duration, Saccade amplitude, Association field, saliency
Subjects:C Biological Sciences > C830 Experimental Psychology
Divisions:College of Social Science > School of Psychology
ID Code:16368
Deposited On:07 Jan 2015 16:30

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