Less Salient, More Capture: The Curious Case of Abrupt Onsets

Abrupt onsets are commonly assumed to capture attention due to their high physical salience. Using a technique recently introduced by Stilwell et al. (2023), we directly compared the salience level of a color singleton, an abrupt onset, and a color singleton + abrupt onset item. We then assessed the magnitude of capture by these items in a visual search task, in which these items served as distractors. In an oddball-detection task, 26 participants reported the presence or absence of the critical item among four heterogeneous shapes. Applying the exact algorithm from Stilwell et al. (2023), we determined the exposure threshold for each item type. Abrupt onsets exhibited a significantly larger exposure threshold (61 ms), indicating lower salience, compared to color singletons (25 ms; t(25) = 5.41, p < .001) and color singleton + abrupt onset items (22 ms; t(25) = 5.92, p < .001). Next, another group of 30 participants completed a visual search task with the same display. Surprisingly, only the pure onset distractor elicited a capture effect, as indicated by response time differences (23.5 ms, t = 5.46, p < .001). In contrast, we found suppression effects for both the color singleton distractor (29.1 ms, t = 5.28, p < .001) and the color singleton + abrupt onset distractor (26.3 ms, t = 3.45, p < .001). The interaction between distractor presence and distractor type was highly significant, F(2, 58) = 30.15, p < .001. Finally, these findings were replicated when the same group of participants (N = 26) completed both tasks. Overall, individuals could suppress an abrupt onset distractor with high salience but not with lower salience. These results suggest that abrupt onsets maintain a privileged status in the visual system and tend to capture attention, despite their relatively low salience.