Interrelation of kinetic and stereoscopic depth: behavior and physiology in vertebrates.

The target article gathers compelling behavioral evidence that motion parallax provides depth information in a variety of animal species. A more general evaluation of kinetic depth cues subserving depth perception would call attention to recent studies in monkeys, demonstrating the interrelation of kinetic and stereoscopic depth cues both on a behavioral and physiological level. Furthermore, it is argued that binocularity in birds has a clear function in stereopsis.