Final answer:
To compare relations between objects and guide movements, the brain uses depth perception through monocular and binocular cues. Monocular cues come from the two-dimensional visual field, while binocular cues compare different eye perceptions for depth and motion analysis. The brain's parallel pathways process what objects are and their location or movement in space.
Step-by-step explanation:
To understand the different spatial information needed to determine relations between objects compared to the information required to guide eye, hand, or limb movements, we need to delve into the realm of depth perception and visual processing in the brain. Depth perception is key for recognizing spatial relationships in a three-dimensional space, allowing us to detect whether objects are in front, behind, above, below, or to the side of other things.
There are two main types of cues used to gather depth information from the retinal signal: monocular cues and binocular cues. Monocular cues rely on information within the two-dimensional visual field, such as an object overlapping another or relative size differences. In contrast, binocular cues involve comparing the slightly different images captured by each of our two eyes. The brain processes these differences to perceive depth and the relative position of objects, even assessing motion in space when objects move at different rates in each eye's field of vision.
Furthermore, the brain processes visual information through parallel pathways—the 'what pathway' for object recognition and identification, and the 'where/how pathway' for locating objects in space and how one might interact with them. This exemplifies how the brain uses spatial information to distinguish relations and guide movements differently, catering to the specifics of each task.