Final answer:
Binocular disparity, also known as retinal disparity, is a depth cue based on the slightly different images that each eye perceives due to the eyes' horizontal separation, allowing the brain to perceive depth in the environment.
Step-by-step explanation:
The difference between the image of a scene received by the right eye and that received by the left eye can serve as a depth cue termed binocular disparity. Binocular disparity, sometimes also called retinal disparity, is the slightly different view of the world that each of our eyes receives due to the horizontal separation between them. This disparity is crucial for depth perception, as our brain processes these different images to gauge the relative distances of objects in our environment.
Other depth cues include monocular cues, which only require one eye and are based on size, overlap, perspective, and other aspects of objects within a two-dimensional visual field. However, binocular cues like binocular disparity offer a unique and vital way to perceive the three-dimensionality of the world, and are the basis of how 3-D movies create the illusion of depth on a two-dimensional screen.