Nonspecific competition underlies transient attention.

Cueing a target by abrupt visual stimuli enhances its perception in a rapid but short-lived fashion, an effect known as transient attention. Our recent study showed that when targets are cued at a constant, central location, the emergence of the transient performance pattern was dependent on the presence of competing distractors, whereas targets presented in isolation were enhanced in a sustained manner (Wilschut et al., PLoS ONE, 6:e27661, 2011). The current study examined in more detail whether the transience depends on the specific nature of the competition. We first replicated and extended the competition-dependent transient pattern for peripheral and variable target locations. We then investigated the role of feature similarity, compatibility, and proximity. Both competition by feature similarity and compatibility between the target and distractors were found to impair performance, but effects were additive with the effects of the cueing interval and did not change the transient performance function. Varying the spatial distance between target and distractors yielded mixed evidence, but here too a transient pattern could be observed for targets flanked by both close and far distractors. The results thus show that the presence or absence of competition determines whether attention appears transient or sustained, while the specific nature of the competition (in terms of location or feature) affects selection independent of time.