Auditory enhancement of visual searches for event scenes

The label-feedback effect is influenced by target category in visual search

The label-feedback hypothesis states that language can modulate visual processing. In particular, hearing or reading aloud target names (labels) speeds up performance in visual search tasks by facilitating target detection and such advantage is often measured against a condition where the target name is shown visually (i.e. via the same modality as the search task). The current study conceptually complements and expands previous investigations. The effect of a multimodal label presentation (i.e., an audio+visual, AV, priming label) in a visual search task is compared to that of a multimodal (i.e. white noise+visual, NV, label) and two unimodal (i.e. audio, A, label or visual, V, label) control conditions. The name of a category (i.e. a label at the superordinate level) is used as a cue, instead of the more commonly used target name (a basic level label), with targets belonging to one of three categories: garments, improper weapons, and proper weapons. These categories vary for their structure, improper weapons being an ad hoc category (i.e. context-dependent), unlike proper weapons and garments. The preregistered analysis shows an overall facilitation of visual search performance in the AV condition compared to the NV condition, confirming that the label-feedback effect may not be explained away by the effects of multimodal stimulation only and that it extends to superordinate labels. Moreover, exploratory analyses show that such facilitation is driven by the garments and proper weapons categories, rather than improper weapons. Thus, the superordinate label-feedback effect is modulated by the structural properties of a category. These findings are consistent with the idea that the AV condition prompts an "up-regulation" of the label, a requirement for enhancing the label's beneficial effects, but not when the label refers to an ad hoc category. They also highlight the peculiar status of the category of improper weapons and set it apart from that of proper weapons.

Semantically congruent bimodal presentation modulates cognitive control over attentional guidance by working memory

Although previous studies have well established that audiovisual enhancement has a promoting effect on working memory and selective attention, there remains an open question about the influence of audiovisual enhancement on attentional guidance by working memory. To address this issue, the present study adopted a dual-task paradigm that combines a working memory task and a visual search task, in which the content of working memory was presented in audiovisual or visual modalities. Given the importance of search speed in memory-driven attentional suppression, we divided participants into two groups based on their reaction time (RT) in neutral trials and examined whether audiovisual enhancement in attentional suppression was modulated by search speed. The results showed that the slow search group exhibited a robust memory-driven attentional suppression effect, and the suppression effect started earlier and its magnitude was greater in the audiovisual condition than in the visual-only condition. However, among the faster search group, the suppression effect only occurred in the trials with longer RTs in the visual-only condition, and its temporal dynamics were selectively improved in the audiovisual condition. Furthermore, audiovisual enhancement of memory-driven attention evolved over time. These findings suggest that semantically congruent bimodal presentation can progressively facilitate the strength and temporal dynamics of memory-driven attentional suppression, and that search speed plays an important role in this process. This may be due to a synergistic effect between multisensory working memory representation and top-down suppression mechanism. The present study demonstrates the flexible role of audiovisual enhancement on cognitive control over memory-driven attention.

The dissociation of semantically congruent and incongruent cross-modal effects on the visual attentional blink

Introduction

Recent studies have found that the sound-induced alleviation of visual attentional blink, a well-known phenomenon exemplifying the beneficial influence of multisensory integration on time-based attention, was larger when that sound was semantically congruent relative to incongruent with the second visual target (T2). Although such an audiovisual congruency effect has been attributed mainly to the semantic conflict carried by the incongruent sound restraining that sound from facilitating T2 processing, it is still unclear whether the integrated semantic information carried by the congruent sound benefits T2 processing.

Methods

To dissociate the congruence-induced benefit and incongruence-induced reduction in the alleviation of visual attentional blink at the behavioral and neural levels, the present study combined behavioral measures and event-related potential (ERP) recordings in a visual attentional blink task wherein the T2-accompanying sound, when delivered, could be semantically neutral in addition to congruent or incongruent with respect to T2.

Results

The behavioral data clearly showed that compared to the neutral sound, the congruent sound improved T2 discrimination during the blink to a higher degree while the incongruent sound improved it to a lesser degree. The T2-locked ERP data revealed that the early occipital cross-modal N195 component (192-228 ms after T2 onset) was uniquely larger in the congruent-sound condition than in the neutral-sound and incongruent-sound conditions, whereas the late parietal cross-modal N440 component (400-500 ms) was prominent only in the incongruent-sound condition.

Discussion

These findings provide strong evidence that the modulating effect of audiovisual semantic congruency on the sound-induced alleviation of visual attentional blink contains not only a late incongruence-induced cost but also an early congruence-induced benefit, thereby demonstrating for the first time an unequivocal congruent-sound-induced benefit in alleviating the limitation of time-based visual attention.