Auditory Attentional Load Modulates Audiovisual Integration During Auditory/Visual Discrimination

Attention modulates numerous stages of audiovisual integration, and studies have shown that audiovisual integration is higher in attended conditions than in unattended conditions. However, attentional resources are limited for each person, and it is not yet clear how audiovisual integration changes under different attentional loads. Here, we explored how auditory attentional load affects audiovisual integration by applying an auditory/visual discrimination task to evaluate audiovisual integration and a rapid serial auditory presentation (RSAP) task to manipulate auditory attentional resources. The results for peak benefit and positive area under the curve of different probability showed that audiovisual integration was highest in the low attentional load condition and lowest in the high attentional load condition (low > no = medium > high). The peak latency and time window revealed that audiovisual integration was delayed as the attentional load increased (no < low < medium < high). Additionally, audiovisual depression was found in the no, medium, and high attentional load conditions but not in the low attentional load condition. These results suggest that mild auditory attentional load increases audiovisual integration, and high auditory attentional load decreases audiovisual integration.