Relative contributions of oculomotor capture and disengagement to distractor-related dwell times in visual search.

In visual search, attention is reliably captured by salient distractors and must be actively disengaged from them to reach the target. In such attentional capture paradigms, dwell time is measured on distractors that appear in the periphery (e.g., on a random location on a circle). Distractor-related dwell time is typically thought to be largely due to stimulus-driven processes related to oculomotor capture dynamics. However, the extent to which oculomotor capture and oculomotor disengagement contribute to distractor dwell time has not been known because standard attentional capture paradigms cannot decouple these processes. In the present study, we used a novel paradigm combining classical attentional capture trials and delayed disengagement trials. We measured eye movements to dissociate the capture and disengagement mechanisms underlying distractor dwell time. We found that only two-thirds of distractor dwell time (~ 52 ms) can be explained by oculomotor capture, while one-third is explained by oculomotor disengagement (~ 18 ms), which has been neglected or underestimated in previous studies. Thus, oculomotor disengagement (goal-directed) processes play a more significant role in distractor dwell times than previously thought.