Esha Brar¹, Han Zhang², John Jonides³; ¹University of Michigan

Abrupt onsets have been known to capture attention. Is it because abrupt onsets are highly salient? In this experiment, we objectively quantified the level of salience and then examined if more salient onsets lead to greater oculomotor capture. Using the psychophysical procedure developed by Stilwell et al. (2023), we measured the salience levels of abrupt onsets, color singletons, and color-singleton abrupt onsets. In phase one, on each trial, participants (N=54) reported whether the critical item was absent or present, with the display duration dynamically adjusted based on previous trial performance. In phase two, the same participants completed a visual search task in which instead of being the target of detection, abrupt onsets, color singletons, and color-singleton abrupt onsets served as distractors. In phase one, we found that participants needed a longer time to detect abrupt onsets compared to color singletons and color-singleton abrupt onsets, suggesting that abrupt onsets were the least salient among the three. However, only abrupt onsets captured attention in the visual search task of phase two. Abrupt onsets induced a distractor-presence cost in reaction times (RT) and captured initial eye movements. Color singleton and color-singleton abrupt onsets induced a distractor-presence benefit in RT, and initial eye movements to these distractors were suppressed. These results suggest that abrupt onsets can capture attention, but not necessarily because they are physically salient.