Do alerting signals increase the size of the attentional focus?

Testing the saliency-based account of phasic alertness

As an essential component of the human attention system, the effect of phasic alertness refers to the change of performance with the presence of a preceding warning signal. Weinbach and Henik (Cognition, 133 (2), 414-419, 2014) argued that phasic alertness is an adaptive mechanism that diverts attention to salient events. This mechanism enhances selective attention when the critical event is more salient than others. When selective attention to less salient details is required, phasic alertness can lead to more interference from task-irrelevant information. The experiment on which this saliency-based account of phasic alertness is based has not been replicated. In two experiments, the present study attempted to replicate the alertness-related findings of Weinbach and Henik. Although we used a similar design, the results did not reveal evidence for an interaction between phasic alertness and response congruency in the global/local processing task. Our results do not support the saliency-based account of phasic alertness. We argue that more systematic investigation is needed for this phasic alertness account.

Warning signals only support the first action in a sequence

Acting upon target stimuli from the environment becomes faster when the targets are preceded by a warning (alerting) cue. Accordingly, alerting is often used to support action in safety-critical contexts (e.g., honking to alert others of a traffic situation). Crucially, however, the benefits of alerting for action have been established using laboratory tasks assessing only simple choice reactions. Real-world actions are considerably more complex and mainly consist of sensorimotor sequences of several sub-actions. Therefore, it is still unknown if the benefits of alerting for action transfer from simple choice reactions to such sensorimotor sequences. Here, we investigated how alerting affected performance in a sequential action task derived from the Trail-Making-Test, a well-established neuropsychological test of cognitive action control (Experiment 1). In addition to this task, participants performed a classic alerting paradigm including a simple choice reaction task (Experiment 2). Results showed that alerting sped up responding in both tasks, but in the sequential action task, this benefit was restricted to the first action of a sequence. This was the case, even when multiple actions were performed within a short time (Experiment 3), ruling out that the restriction of alerting to the first action was due to its short-lived nature. Taken together, these findings reveal the existence of an interface between phasic alertness and action control that supports the next action.

Effects of a neutral warning signal under increased temporal uncertainty

Han and Proctor (2022a, Quarterly Journal of Experimental Psychology, 75[4], 754-764) reported that in a visual two-choice task, compared with a no-warning condition, a neutral warning tone caused shorter reaction times (RTs) but at the expense of an increase in error percentages (a speed-accuracy trade-off) at a constant 50-ms foreperiod but shorter RTs without an increase in error percentages at a 200-ms foreperiod. Also, the spatial compatibility of stimulus-response mappings was found to interact with the foreperiod effect on RT. We conducted three experiments to investigate whether these findings can be replicated without the constancy of foreperiod within a trial block. In Experiments 1 and 2, participants performed the same two-choice task as in Han and Proctor's study but with the foreperiod randomly varied among 50, 100, and 200 ms and RT feedback provided after each response. Results showed that as the foreperiod increased, RT decreased while EP increased, demonstrating a consistent speed-accuracy trade-off. Also, the mapping effect was found to be largest at the 100-ms foreperiod. In Experiment 3, RT feedback was not provided, and the warning tone speeded responses without evidence of an increase in error percentage. We conclude that the enhanced information processing at a 200-ms foreperiod depends on constancy of foreperiod within a trial block, whereas the mapping-foreperiod interaction found in Han and Proctor is relatively unaffected by increased temporal uncertainty.

Is the alerting-congruency interaction that is seen in experiments with stimulus-response motor associations moderated by a concurrent working-memory load?

The mechanisms underlying attention, distraction, and cognitive control have been widely studied, and results consistently show that reaction times are affected by alerting cues as well as by concurrent distraction. In addition, when distractors have pre-existing directional motor associations, alerting and distractor congruency interact in a manner where distractors have a larger effect when people are alerted to an upcoming target relative to when people are not alerted to the target's presentation. However, does a concurrent working memory load moderate this interaction in multitasking experiments, and if so, does it magnify or suppress this effect? The current study (N = 40) finds that although a memory-load significantly slows reaction times it does not moderate the alerting-congruency interaction. Discussion focuses on theoretical and applied implications of this empirical result.

Effects of a neutral warning signal on spatial two-choice reactions

Posner et al. reported that, at short fixed foreperiods, a neutral warning tone reduced reaction times (RTs) in a visual two-choice task while increasing error rates for both spatially compatible and incompatible stimulus-response mappings. Consequently, they concluded that alertness induced by the warning does not affect the efficiency of information processing but the setting of a response criterion. We conducted two experiments to determine the conditions under which the trade-off occurs. In Experiment 1, participants performed the same two-choice task as in Posner et al.'s study without RT feedback. Results showed that the warning tone speeded responses with no evidence of speed/accuracy trade-off. In Experiment 2, RT feedback was provided after each response, and a speed/accuracy trade-off was found for the 50-ms foreperiod. However, better information-processing efficiency was evident for the 200-ms foreperiod. We conclude that the foreperiod effect of a 50-ms foreperiod is a result of response criterion adjustment and that providing trial-level RT feedback is critical for replicating this pattern. However, fixed foreperiods of 200 ms or longer benefit both speed and accuracy, implying a more controlled preparation component that improves response efficiency.

A nonspatial sound modulates processing of visual distractors in a flanker task

Successful navigation of information-rich, multimodal environments involves processing of both auditory and visual information. The extent to which information within each modality is processed varies due to many factors, but the influence of auditory stimuli on the processing of visual stimuli in these multimodal environments is not well understood. Previous research has shown that a preceding sound leads to decreased reaction times in visual tasks (Bertelson, 1967). The current study examines if a non-spatial, task-irrelevant sound additionally alters processing of visual distractors that flank a central target. We utilized a version of a flanker task in which participants responded to a central letter surrounded by two irrelevant flanker letters. When these flankers are associated with a conflicting response, a congruency effect occurs such that reaction time to the target is slowed (Eriksen & Eriksen, 1974). In two experiments using this task, results showed that a preceding tone caused general speeding of reaction time across flanker types, consistent with alerting. The tone also caused decreased variation in response time. Critically, the tone modulated the congruency effect, with a greater speeding for congruent flankers than for incongruent flankers. This suggests that the influence of flanker identity was more intense after tone presentation, consistent with a nonspatial sound increasing perceptual and/or response-association processing of flanking stimuli.

Audiovisual integration capacity modulates as a function of illusory visual contours, visual display circumference, and sound type

Research into the capacity of audiovisual integration has previously assessed whether capacity is strictly limited to a single item, or whether it can exceed one item under certain environmental conditions. More recently, investigations have turned to examining the effects of various stimulus factors on capacity. Across two experiments, we looked at a number of factors that were expected to play a modulatory role on capacity. Experiment 1 deployed a manipulation of illusory polygons, revealing an increase in audiovisual capacity, even in an absence of visual connections. This demonstrates that exceeding the capacity of 1 does not only represent a functional increase in the binding of a singular, complex visual object, but that it can also represent binding of multiple simpler objects. Findings also support the hypothesis that capacity modulates quantitatively, but not qualitatively, with respect to speed of presentation. Experiment 2 examined the effects of different sound types (sine tones or white noise) and of different spatial visual field sizes on the capacity of audiovisual integration. The results indicate that capacity is maximized when stimuli are presented in a smaller circle (7.5°) if alongside a sine tone, and when presented in a larger circle (18.5°) alongside white noise. These results suggest that audiovisual integration capacity is dependent on the combination of sound type and visual spatial field size. The combination of these results reveal additional phenomenological features of the capacity of audiovisual integration, and provides impetus for further research into applications of the findings.