If depth perception works because the brain checks the difference in the position of the object between the two eyes and concludes how far away it is, how can we still see depth when one eye is closed?
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You can’t, not really. However, your brain will try to guess based on your experiences, shape, shadows, size… It’s the same as when you’re watching a movie: there’s no depth, but you can still tell that a building in the background is farther than the person speaking.
Try this: cover one of your eyes with an eye patch (pice of cloth for example). Stay that way for a bit, then try to reach for things (small, suspended ones worked well in my experience). You’ll see that while you have a general idea of how far things are, but trying to tell where they actually are in order to tell your hands where to go is a different matter.
For most situations, our brains have developed multiple “checks” to determine distance.
First and foremost is depth perception from our eyes both working.
After that, it’ll check things like relative size of objects. For instance, when you’re driving, they tell you to check multiple times for motorcycles. The reason is that our brains learned to understand that something small is probably far away, so when we’re seeing a motorcycle that is much smaller than a car, our brain instinctively thinks it is far away. But if you look at in a few seconds later, your brain understands that it’s actually not far away.
Shadows and other things also give us depth perception.
The only time people struggle to judge distance with only one eye is when there’s only one or two visual cues to go by. A ball traveling through the air is significantly harder to catch with one eye, because the only real visual cue to judge the distance and position is having the stereoscopic vision from both eyes.
You think you can see depth, but in reality it’s your brain giving you a best estimate based on knowledge of sizes, shadows, movement, sound, but in to see true depth with one eye is simply impossible. To proof this you can ask someone to hold a finger in front of you, somewhere between your eyes and almost your maximum reaching length of your arm (this will be somewhere around 0 to 60cm, 0 to 2 feet). Now to touch this finger from the side is easy with two eyes. Touching it with one eye? You’ll miss most of the time.
You think you can see depth, but in reality it’s your brain giving you a best estimate based on knowledge of sizes, shadows, movement, sound, but in to see true depth with one eye is simply impossible. To proof this you can ask someone to hold a finger in front of you, somewhere between your eyes and almost your maximum reaching length of your arm (this will be somewhere around 0 to 60cm, 0 to 2 feet). Now to touch this finger from the side is easy with two eyes. Touching it with one eye? You’ll miss most of the time.
You think you can see depth, but in reality it’s your brain giving you a best estimate based on knowledge of sizes, shadows, movement, sound, but in to see true depth with one eye is simply impossible. To proof this you can ask someone to hold a finger in front of you, somewhere between your eyes and almost your maximum reaching length of your arm (this will be somewhere around 0 to 60cm, 0 to 2 feet). Now to touch this finger from the side is easy with two eyes. Touching it with one eye? You’ll miss most of the time.
Neural networks, your brain creates a model of the world and constantly checks that model against reality.
So for instance, say I see a stop sign up ahead. I’ve already seen many stop signs, so my brain already has a pretty good idea of how big it should be. If only one eye is open, the brain can’t directly measure depth, but it can use those estimates based on how big I know a stop sign should be in order to approximate how far away it is.
And honestly, 99% of the time you don’t need full information, because the estimates are usually pretty accurate – however, optical illusions exploit this knowledge to have your brain create a mental image that isn’t actually there.
You can’t. Try playing tennis with one eye closed. The ball doesn’t come at you, it just gets bigger.
You can’t, OP.
Wear a patch on one eye for a day or two. Eventually, you’ll lose your depth perception.
I have amblyopia. I have never had depth perception.
As someone who only has one good eye (my left eye has a very narrow field of vision, I can actually see further to the left with my right eye than my left eye), I use various tricks like shadows, known size vs apparent size, movement, etc to judge depth. This works fine for normal everyday tasks, but where I started to notice problems is driving. I have no real depth perception, and I just can’t judge depth well enough at vehicle speeds so I don’t drive.
Lots of people ignoring the fact that your eyes have to change shape to focus much like a camera lens. You can perceive depth this way by racking focus between different objects.
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