texture gradient monocular depth perception cue, the tendency for textured surfaces to appear to become smaller and finer as distance from the viewer increases. motion parallax monocular depth perception cue, perception of motion of objects in which close objects appear to move more the quickly than objects that are farther away. accommodation as a monocular cue of depth percep- tion, the brain's use of information about the changing thickness of the lens of the eye in response to looking at objects that are close or far away.