Preparing for distraction: Attention is enhanced prior to the presentation of distractors

How do people prepare for the presentation of distractors, if at all? Previous studies have shown that sometimes, paradoxically, observers actively allocate attention to expected distractors. However, this was mainly found in selective-attention tasks in which to-be-attended targets were also expected. The present experiments are designed to probe attention when the only stimuli expected to appear in the display are distractors. Specifically, participants performed a change-detection task while interfering stimuli appeared at a fixed moment during the retention interval. Additionally, they were asked to respond to a dot-probe that appeared unexpectedly in a small proportion of the trials. Experiment 1 found that participants were faster to detect the probe when it appeared in distractor blocks than in no-distractor blocks, both when the probe appeared at the exact moment of the expected distractor and earlier. Experiment 2 showed a similar effect when the expected stimuli were informative, rather than distracting, confirming that people actively allocate attention to all upcoming stimuli. Experiments 3 to 5 replicated and extended the preparation effect by showing that it was not spatially specific. Experiments 6 and 7 ruled out alternative explanations concerning temporal uncertainty and general arousal. Together, these findings strongly suggest that observers not only do not inhibit distractors prior to their presentation but, in fact, allocate more attentional resources when expecting distractors. This enhancement is not temporally or spatially specific, suggesting that the attentional system is more alerted when a stimulus is about to appear, even when it is clear that this stimulus is distracting.