At what age do infants begin to use motion information to judge depth?

Infants begin to use motion-carried information—also known as kinematic information—to judge depth at approximately two months of age. This occurs when an infant observes one surface moving in front of another, providing a visual cue for distance.1

While this sensitivity to motion-based depth cues emerges early, other forms of depth perception develop subsequently. For instance, infants gain the ability to perceive depth through stereopsis (using the difference in optical projections between the two retinas) at about four months of age. By seven months, they are able to perceive depth in two-dimensional pictures, and by eight to ten months, they demonstrate an avoidance reaction to depth when crawling, as observed in experiments using the visual cliff.12