Multisensory integration of looming signals by rhesus monkeys.

Looming objects produce ecologically important signals that can be perceived in both the visual and auditory domains. Using a preferential looking technique with looming and receding visual and auditory stimuli, we examined the multisensory integration of looming stimuli by rhesus monkeys. We found a strong attentional preference for coincident visual and auditory looming but no analogous preference for coincident stimulus recession. Consistent with previous findings, the effect occurred only with tonal stimuli and not with broadband noise. The results suggest an evolved capacity to integrate multisensory looming objects.