Final answer:
Binocular rivalry occurs when different images are shown to each eye, and perception alternates between them, illustrating the brain's active role in constructing our visual reality rather than passively receiving images.
Step-by-step explanation:
The phenomenon where an image is presented to the left eye while a different image is presented to the right eye, leading to a back-and-forth alternate perception, is known as binocular rivalry. This occurs because each eye processes visual information independently before the brain combines the images to give the perception of depth and three-dimensionality, which is the principle behind 3-D movies.
This demonstrates that the brain is not a passive recipient of visual information but an active participant in the construction of our perceptual reality. It adjusts and interprets visual cues such as color and alignment (e.g., the checkerboard illusion) based on various factors, including expected lighting conditions and occlusion (shadow effects). The optic chiasm plays a significant role, as it is the point where the optic nerves cross to allow the visual field to be correctly processed by the opposing hemisphere of the brain.