Stimulus-driven attentional capture by a static discontinuity between perceptual groups.

After C. L. Folk, R. W. Remington, and J. C. Johnston (1992) proposed their contingent-orienting hypothesis, there has been an ongoing debate over whether purely stimulus-driven attentional capture can occur for visual events that are salient by virtue of a distinctive static property (as opposed to a dynamic property such as abrupt onset). The present study identified 3 methodological criteria for establishing that attentional capture is stimulus driven and not contingent on top-down attentional control settings. In 5 experiments, attentional capture occurred for a static discontinuity at the boundary between one group of homogeneous items (red Xs) abutted next to a group of homogeneous items that were featurally different (green Xs) within a single row. Experiment 1 intentionally violated one of the criteria for demonstrating stimulus-driven capture so as to establish that contingent attentional capture can occur for this novel type of static cue. In the remaining 4 experiments, even with all 3 criteria for stimulus-driven capture partially or completely satisfied, the static discontinuity captured attention. These attentional capture effects are the first to be obtained when all 3 criteria for establishing that they are purely stimulus driven have been satisfied.