Sound gaps boost emotional audiovisual integration independent of attention: Evidence from an ERP study

The emotion discrimination paradigm was adopted to study the effect of interrupted sound on visual emotional processing under different attentional states. There were two experiments: Experiment 1: judging facial expressions (explicit task), Experiment 2: judging the position of a bar (implicit task). In Experiment 1, ERP results showed that there was a sound gap accelerating the effect of P1 present only under neutral faces. In Experiment 2, the accelerating effect (P1) existed regardless of the emotional condition. Combining two experiments, P1 findings suggest that sound gap enhances bottom-up attention. The N170 and late positive component (LPC) were found to be regulated by emotion face in both experiments, with fear over the neutral. Comparing the two experiments, the explicit task induced a larger LPC than the implicit task. Overall, sound gaps boosted the audiovisual integration by bottom-up attention in early integration, while cognitive expectations led to top-down attention in late stages.