Visual search clearly benefits from knowledge about relevant features. However, despite substantial evidence that stimulus timing also affects visual search performance, the effect of temporal certainty on visual search processes, and especially on distractor suppression, remains unclear. Can distractors be suppressed more effectively if we know when to expect them? Considering temporal positions as feature-like information, we examine temporal influences by varying temporal certainty of visual stimuli in a conjunction search experiment (N=40). Participants search for a red vertical bar among four differently orientated, colored bars, or have to suppress the red vertical bar and, instead, search for a non-red vertical bar. The target display is preceded by a cueing display - proactive processing is expected to result in shorter (search condition; due to facilitation) or longer (suppression condition; due to suppression) reaction times in trials in which the red cue and the target are presented at the same position compared to different-position trials.
We evaluate the impact of temporal certainty by implementing two different types of trial blocks; with certain (100 ms or 200 ms) or uncertain (mixed) cue-target intervals. Temporal certainty is hypothesized to result in stronger cueing effects (i.e., facilitation or suppression, depending on condition) of same-position vs. different-position cues compared to temporally uncertain trials.
Results are discussed in light of current theories and constitute significance for central aspects of everyday life, by revealing the impact of temporal certainty on attention control.