Independent Multisensory Integration and Crossmodal Attention Processing: Evidence from Audiovisual Gender Congruency Tasks

Multisensory integration and crossmodal attention are two of the basic mechanisms in processing multisensory inputs, and they are usually mixed. Whether these two processes are dependent or independent remains controversial. To examine the relationship between multisensory integration and crossmodal attention, we adopted modified multilevel audiovisual gender judgment paradigms and evaluated the congruency effects in reaction time (RT) and the inverse effectiveness (IE) effects. If they were dependent, the occurrence of one effect would be accompanied with that of the other. Using both morphed faces and voices, we first performed a speeded classification task, in which participants were either asked to attend to faces (experiment 1a) or attend to voices (experiment 1b); then, we performed an unspeeded rating task with faces as the targets (experiment 2). We observed both a congruency effect in RT and an IE effect in experiment 1a, a congruency effect in RT alone in experiment 1b, and an IE effect alone in experiment 2. These results indicate that the two processes are independent of each other.