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Published July 24, 2012 | public
Journal Article Open

A Simple Strategy for Detecting Moving Objects during Locomotion Revealed by Animal-Robot Interactions


An important role of visual systems is to detect nearby predators, prey, and potential mates, which may be distinguished in part by their motion. When an animal is at rest, an object moving in any direction may easily be detected by motion-sensitive visual circuits. During locomotion, however, this strategy is compromised because the observer must detect a moving object within the pattern of optic flow created by its own motion through the stationary background. However, objects that move creating back-to-front (regressive) motion may be unambiguously distinguished from stationary objects because forward locomotion creates only front-to-back (progressive) optic flow. Thus, moving animals should exhibit an enhanced sensitivity to regressively moving objects. We explicitly tested this hypothesis by constructing a simple fly-sized robot that was programmed to interact with a real fly. Our measurements indicate that whereas walking female flies freeze in response to a regressively moving object, they ignore a progressively moving one. Regressive motion salience also explains observations of behaviors exhibited by pairs of walking flies. Because the assumptions underlying the regressive motion salience hypothesis are general, we suspect that the behavior we have observed in Drosophila may be widespread among eyed, motile organisms.

Additional Information

© 2012 Elsevier Ltd. Received: April 10, 2012; Revised: May 2, 2012; Accepted: May 11, 2012; Published online: June 21, 2012. We wish to thank Andrew Straw for his help with the design of experiments and the development of the software used to create the "fly's eye view" in Movie S2. Peter Weir and Joel Levine provided helpful comments on the manuscript. Funding for this research was provided by US National Institutes of Health grant R01 DA022777 (M.H.D. and P.P.), US National Science Foundation grant 0623527 (M.H.D.), ONR MURI grant 1015-G-NA-127 (P.P.), and the Paul G. Allen Family Foundation (M.H.D.).

Attached Files

Supplemental Material - mmc1.mp4

Supplemental Material - mmc2.mp4

Accepted Version - nihms389033.pdf


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August 19, 2023
August 19, 2023