Perceptual constraints of motion shape animal movement strategies

Abstract

As animals explore their environment, self-generated motion can affect visual perception, while perceptual constraints shape movement decisions. Movement strategies should therefore balance the benefits of exploration against the potential perceptual costs of motion. Here, we test whether the movement strategies animals adopt can enhance information acquisition while accounting for the constraints that motion imposes on visual perception. We first quantified the visual perceptual abilities of freely moving fish in three dimensions by projecting virtual prey around three-spined sticklebacks (Gasterosteus aculeatus), determining how the likelihood of detecting prey varied across the fish's visual field as a function of their movement. Self-induced motion reduced the likelihood prey were detected, with increases in speed non-linearly reducing the perceptual abilities of the fish. Using agent-based simulations based on empirical models of visual perception, we demonstrate that when visual perception degrades non-linearly with speed, the strategy that maximizes prey detection is 'saltatory' locomotion, involving stationary pauses interspersed with movements. Moreover, experiments with freely swimming fish showed they adopted specific durations of stops and movements that improved prey detection given the way motion impacts their perception. Our results reveal that some movement strategies are more effective than others at gathering information during exploration.