Phasic alertness: Do warning tones exacerbate interference from salient distractors?

Using a global/local processing task, Weinbach and Henik (Cognition 133 (2), 414-419, 2014) found that an alerting tone modulated attentional bias for salient stimuli, increasing interference when they were irrelevant to the task. They proposed that phasic alertness broadens attentional focus, increasing one's susceptibility to salient distractors. However, Han and Proctor (2023) failed to replicate their finding using the same task. Here we approached this question with a different paradigm that is commonly used to assess capture by salient color singletons. Specifically, we asked whether phasic alertness amplifies attention capture by salient color singletons. In Experiment 1, participants searched for a predefined target shape among five heterogeneous shapes, which sometimes contained irrelevant colored distractors. The critical manipulation was whether the colored distractor was salient (one irrelevant colored distractor; a singleton) or non-salient (three irrelevant colored distractors; a triplet). The alerting tone was present prior to the search display on half of the trials. Although alerting generally sped up target search, alerting did not increase capture by irrelevant color singletons compared to triplets. Similar results were obtained in Experiment 2 when we promoted capture by the salient color singleton by making it task relevant. Contrary to the saliency-based phasic alertness account, we found no evidence that alerting makes people more susceptible to being captured by salient distractors. PUBLIC SIGNIFICANCE STATEMENTS: Warning tones are often used in real-world contexts to alert users that some task needs to be performed. Understanding how they affect our performance is important for improving safety. Previous studies have suggested that warning tones not only prepare us to do the task but can also have a negative side effect. They may bias our attention to unique but irrelevant salient distractors, increasing their ability to disrupt task performance. However, our study suggests that this negative side effect does not always occur. We found no evidence that an alerting tone increased susceptibility to capture by salient distractors.