Individual differences in first saccade latency predict overt behaviour during search for a contour integration target

During everyday functioning, the visual world is explored by using saccadic eye movements to direct the information-rich fovea to specific locations. These eye movements are guided by visual input from outside of the fovea, where processes of perceptual organization piece together scene and object structure, including contour information. The current study investigates variation in how the typical population uses eye movements to complete a search for a closed-contour target formed by oriented gabor patches. Performance at contour integration tasks varies across a range of clinical populations, although it is unknown the degree to which performance differs within the typical population and if these differences relate to how individuals move their eyes during the task. The results show large variation in first saccade latency between individuals, with these differences correlating with first saccade accuracy and the total number of fixations needed to complete the task. Within-subject performance variation across trials mirrored these effects, although equivalent changes in first saccade latency did not influence saccadic behavior for all participants in the same way. This finding that longer first saccade latency improves eye movement guidance differently across participants is discussed in terms of the potential benefits of having additional time for recurrent processing and individual differences in ability to spatially spread attention.