Previous work has shown that abrupt visual onsets capture attention. Possible mechanisms for this phenomenon include: (a) a luminance-change detection system and (b) a mechanism that detects the appearance of new perceptual objects. Experiments 1 and 2 revealed that attention is captured in visual search by the appearance of a new perceptual object even when the object is equiluminant with its background and thus exhibits no luminance change when it appears. Experiment 3 showed that a highly salient limunance increment alone is not sufficient to capture attention. These findings suggest that attentional capture is mediated by a mechanisms that detects the appearance of new perceptual objects.
Abstract