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Competing Viewpoints
Did you know that your two eyes do not see the same image? Cover one eye at a time and you'll see the difference. It's subtle but important. The similar-yet-distinct images are integrated in the brain and this visual fusion is responsible for depth perception and stereopsis.
Vision researchers from UC San Diego are studying why the brain can't fuse dissimilar images. For example, wearing glasses with one yellow lens and one blue lens will not create a green world. At any instant the brain decides to accept one image or the other, never both.
Retinal rivalry is the explanation for the brain's inability to fuse two different visual images.
This phenomenon also occurs in the tangible world. If you hold an apple with both hands you don't feel two apples, do you?
Here's a neat visual experiment for students scratching for science fair ideas. Prepare two 8"x8" cards with diagonal stripe patterns as seen above. Tape them onto a wall or other vertical surface 3 inches apart. Then insert a third plain card perpendicular to the wall between the two cards as a dividing barrier.
Bring your face close so that the eyes can only see each card separately. Intuitively you might suspect that the two patterns would fuse to create a diamond grid. Not so! Instead most viewers appreciate either one diagonal pattern or an alternating, wiggling mosaic.
Understanding the phenomenon of retinal rivalry has provided great insights (yes, a horrid pun) regarding visual changes in stroke victims and for patients with crooked eyes.
Want to learn more? Direct both of your eyes to the recent issue of Scientific American Mind cited below.
REFERENCE: Scientific American Mind (Dec06/Jan07) 'When the Two Eyes Clash'. pages 16-18.
Related Topics: Technorati Tags: vision, eyes, retinal rivalry, amblyopia, lazy eye, double vision, stroke vision, health-and wellness
Vision researchers from UC San Diego are studying why the brain can't fuse dissimilar images. For example, wearing glasses with one yellow lens and one blue lens will not create a green world. At any instant the brain decides to accept one image or the other, never both.
Retinal rivalry is the explanation for the brain's inability to fuse two different visual images.
This phenomenon also occurs in the tangible world. If you hold an apple with both hands you don't feel two apples, do you?
Here's a neat visual experiment for students scratching for science fair ideas. Prepare two 8"x8" cards with diagonal stripe patterns as seen above. Tape them onto a wall or other vertical surface 3 inches apart. Then insert a third plain card perpendicular to the wall between the two cards as a dividing barrier.Bring your face close so that the eyes can only see each card separately. Intuitively you might suspect that the two patterns would fuse to create a diamond grid. Not so! Instead most viewers appreciate either one diagonal pattern or an alternating, wiggling mosaic.
Understanding the phenomenon of retinal rivalry has provided great insights (yes, a horrid pun) regarding visual changes in stroke victims and for patients with crooked eyes.
Want to learn more? Direct both of your eyes to the recent issue of Scientific American Mind cited below.
REFERENCE: Scientific American Mind (Dec06/Jan07) 'When the Two Eyes Clash'. pages 16-18.
Related Topics: Technorati Tags: vision, eyes, retinal rivalry, amblyopia, lazy eye, double vision, stroke vision, health-and wellness
