Perceiving the World Through Echolocation and Vision

Abstract

Bats use echolocation to collect sensory information about the nocturnal scene and use the information to orient and find prey. Like vision, echolocation provides high spatial resolution; however, there are distinct differences among the physical stimuli, receptor organs, and early neural processing of the two distal sensing systems. Nevertheless, a comparison of vision and echolocation reveals some striking parallels that can guide a more informed understanding of higher-level perceptual mechanisms across modalities. Both echolocating bats and visually guided animals aim their central gaze (sonar sound beam or retinal fovea) precisely and sequentially at targets they are attending, although both the acoustic and visual fields of view are broad. There appear to be comparable features in the processing of temporally interrupted sensory input in echolocation and vision: Bats emit short calls separated by comparatively long silences, yielding a “stroboscopic sampling” of the world. Visual information in human observers is suppressed during eye movements, also yielding an interrupted sampling of information. Yet, human observers experience a continuous perceptual world, and we hypothesize that bats’ sonar experience of the world also is continuous, in spite of the interrupted nature of echo snapshots of the environment. Indeed, a comparison of echolocation and vision indicates that beyond early stages of sensorineural processing, higher-order representations of scenes in the two systems may operate on similar principles. In both systems, the perceptual scene must be a functional representation of the layout of the physical scene, allowing the animal to navigate effectively in its surroundings. From this perspective, comparisons of echolocation and vision can lead to broader insights into the common functions of perceptual systems in interpreting sensory input and enabling complex spatial behaviors in dynamic environments.