The visuotactile temporal binding window widens with spatial congruency.

Signals from different senses are integrated into multisensory events
or segregated according to their temporal and spatial relations. If signals are integrated, we perceive synchrony between them even in the presence of slight
stimulus onset asynchronies (SOA). The range of SOAs during which physically
asynchronous signals are perceived to be synchronous is called the temporal
binding window (TBW). The TBW depends on various factors. Here we investigated how spatial congruency affects the width of the visuotactile TBW in a naturalistic setting, given that spatial congruency of signals in the single senses
should promote multisensory integration and thereby binding. In a virtual reality
(VR) environment, we presented visual and vibrotactile stimuli in different locations. Vibrotactile stimuli were presented on the participants’ hands or forearms,
and visual stimuli were rendered in real time on virtual counterparts of the tracked
hands or forearms. We varied SOAs between vision and touch and asked if visual
and tactile stimuli had occurred synchronously. Similar to what has been found
in the audiovisual domain, the temporal binding window was wider when visual
and tactile stimuli were spatially congruent— possibly due to enhanced multisensory integration. Thus, we extend the previous findings and conclusions on
spatial congruency effects to visuotactile interactions in VR environments.