ELi5: How come when there’s something in your field of vision, your eyes can basically “see through” the object when you’re looking past it?
In: Biology
You have two eyes which act like two different cameras for your brain. If you put your finger in front of your right eye and close your left eye you’ll see your finger straight on, but if you close your right eye and open your left eye you’ll see the side of your finger and a more unobstructed view of what’s in front of you. The brain combines these two camera images into one image and uses the size of the gaps caused by objects to determine how far away from you they are so that it can create a single 3D image. When you change what you’re looking at, the brain prioritises giving you the most important image, so if one eye can see past something close to your other eye, it’ll use that information to fill in the image that the blocked eye can’t see. The brain is a very clever editor.
The images your brain gets from your eyes get merged together into one image that you “see.” Since there’s a lot of overlap between the two inputs, objects that don’t match what your brain expects or that are deemed irrelevant (like your nose) are just ignored/erased if there’s enough data to do so, and merged into a composite if there isn’t.
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