Question

Prepare an ONE Page Reflection on Perceiving Depth and Size

Answer 1

Perception and vision are two very complicated things. We are able to see and perceive when Light enters through our eyes as Visual stimuli and reach the photo-receptors located in the retina, where it is transformed into neural impulses. The Impulses then travel through the CNS (Central Nervous System) via the sensory way-station of the thalamus where they are then directed to the Visual Cortex. The Visual Cortex transfers the information to the Parietal Lobe and the Temporal Lobe. Approximately one-third of the Cerebral Cortex has a major role in processing Visual Stimuli.

Perception of Depth: It is the visual ability of three-dimensional perception of the world attributed with the ability to analyze the distance of an object from the eye or lens. Monocular vision (one eye) is very poor at determining depth because when an image is projected on a single retina, signals are generated about the relative size of the object compared to other objects but cannot be compared. In Binocular vision (two eyes), these relative sizes can be compared as two different images are seen based on varying angles of the two individual eyes.

Depth perception is dependant on the convergence of the sight of both eyes on a single object, the relative differences in the shape and size of the images projected on each retina, the relative size of two or more objects in relation to one another, and other hints like the texture. Shape constancy allows an individual to see an object as a single constant shape when seen from two eyes at different angles so that each individual eye recognizes a single shape and not two different images. When the images from both the eyes are compared, Stereopsis occurs i.e., the impression of depth.

Perception of Size: Size of objects are also determined in relation to the image formed in both the eyes of each other. Visual reminders, like distant objects appearing smaller and nearby objects appearing larger, are developed early in life. Convergence of vision at a single point is another visual facility that helps understand distance. Objects tend to converge into a single point as they keep moving farther away in distance from the eyes, an example being the illusion of rails disappearing into each other at a distance.

There are Optical illusions like the Ebbinghaus illusion that show how our perception of size is altered by the change in relative sizes of other objects around what we see. In an experiment, if the size of the surrounding circles is changed keeping the size of one circle intact, an illusion of change in the size of the unchanged circle is created.