Auditory-visual information transfer in echolocating Egyptian fruit bats

Abstract

Egyptian fruit bats have good vision but can also accurately echolocate relying on their well-developed auditory system. We asked two questions: 1. Can these bats acquire a mental image of an object using vision (or hearing) alone? 2. If such a mental image has been formed, can it be transferred from one sensory modality (e.g., vision) to another (e.g., hearing)? We trained the bats to first localize a rewarded object (an X) that was presented pseudo-randomly at either the left or right side using either vision (group 1) or hearing (group 2) alone. After only a few weeks, all experimental bats were able to perform these tasks. We then had the bats discriminate between a rewarded object (the X) and an unrewarded object (a circle) using either vision (group 1) or hearing (group 2) alone. Again, all bats mastered this task after only a few weeks of training. Finally, we tested if the same bats could also discriminate the objects using the other sensory modality (group 1: hearing; group 2: vision). After only a few sessions, the bats performed correctly suggesting that the bats can indeed transform a mental image that they obtained using one sensory modality to another modality.