Attentional capture by onsets and offsets

Abstract

An object that appears abruptly captures attention. To investigate the underlying mechanisms of onset capture, two related questions were asked: (1) Is capture driven by the luminance transients that accompany the onset? (2) Is capture modulated by the observer's attentional set? The questions were addressed by comparing attentional capture by an onset, and an offset, stimulus. If the onset's luminance transients drive, an offset, which also evokes luminance change, should successfully capture attention. Two different top-down contexts were examined: When the target location was defined by (1) a static, and (2) a dynamic, discontinuity. The results showed that an irrelevant onset cue successfully captured attention even when the attentional setting was not programmed to monitor onsets. But, an offset stimulus only captured attention when observers were set, specifically, to monitor an offset, or a luminance change.

Keywords:

• Attentional capture
• Onset capture
• Offset capture
• Attentional control setting

This research was supported by NUS Grant R-581-000-136-112.