Carly J. Leonard¹ (), Ryan V. Ringer¹; ¹University of Colorado Denver

There is no question that individual differences are prevalent across a wide range of psychological and physiological processes. Previous work has shown that this is indeed true for oculomotor behavior, with individuals varying substantially on measures such as average fixation duration and saccade amplitude during visual tasks. Recent studies in our lab have focused on the latency of initial saccades during visual search for a target defined by contour integration. Of particular interest is a speed accuracy tradeoff, such that some individuals tend towards fast first eye movements that land further from the target, while others wait longer and make a more accurate first saccade. The question of interest here is how this initial eye movement behavior relates to task completion (i.e., manual response), as previous results suggested that it may not (Leonard, 2024). To address this, eye movements during visual search were analyzed in a large sample of participants (N = 74). Results replicated previous individual difference findings, showing a correlation between first saccade latency and its landing distance from the target. Critically, the results showed that this first saccade latency did not significantly correlate with manual reaction time. This suggests that while those with slower eye movements may have higher first saccade accuracy, delaying did not directly confer benefits to task performance. More detailed analyses show nuances of how the first saccadic decision is mediated by intermediate saccade behavior and decision time to result in overall manual response speed. These results indicate the importance of considering how small decisions, like that of making a single eye movement, may differ between individuals but not always translate to more comprehensive measures of performance. More broadly, the findings are discussed in terms of how individual differences in a range of processing abilities may interact with eye movement decisions.

Acknowledgements: R15EY035056-01 to CJL