This question started out life as a session of idle wondering; I was sitting thinking whether there would be any surgical technique that would allow me to see my own brain directly (i.e. without the use of mirrors etc; would it be possible to open the skull in such a way that the patient remains conscious, but the eyes have sufficient freedom to be able to see the exposed brain…
Anyway, that got me to thinking about what it would be like if I was able to pop out my eyes and mount them on the sides of my head, facing backwards. In this case, apart from facing the wrong direction for ambulation, the right eye would be on the left side of the new field of view and vice versa.
I haven’t been drinking or anything, honestly.
Anyway, suppose I was able (without disturbing the optic nerve connections) swap my left and right eyes with each other; would my perception of depth be reversed? Would the outside of solid objects start to look more like the inside of hollow ones?
I don’t think it would affect your depth perception at all, off the top of my head. Don’t you swap the position of your left and right eyes when you hang upside down from something?
In any case, perception occurs in the brain, not the eyes (as you know, not being patronizing). It seems like so long as you had eyes facing forward your brain could translate the image.
Near and far would be reversed. If you have red/blue 3D glasses you can test this by putting the glasses on backwards and see for youself that close objects become background and background objects appear closer.
Someone did an experiment on the brain and visual perception when I was in college. Test subjects wore glasses that made things look upside down. Within a short time (a day or so?), things began to look right side up again…until they took their glasses off.
Mangetout, I don’t have depth perception because about 90% of the vision in one of my eyes is gone. I general, I perceive my “self” as being behind my left eye. If I participated in your experiment, I’m wondering what it would do to my mind! Would my consciousness seem to be in a new location?
Do you wear a shirt warning people to stay away from you?
The brain has a remarkable ability to reprogram itself situationally (studies have shown that if you take away vision, that part of the brain is used for other processes like touch, and upon vision returning, the brain re-adapts and vision takes over that part again). Coupled with the study Zoe mentioned, I would WAG that the brain would be confused at first, but re-wire itself to show the “correct” vision (in the same way you feel like you’re swaying when you get off a ship after a week at sea).
How the brain does this is one of the more wonderous things… studies have also shown that the general form of a human face is hard-coded into our brain to aid in recognition (a good explanation of why we can point to some vague form in a chip and say it is a face, but there are disorders where people can’t connect a face to a person any more than they can an elbow). It may be just simple calibration to a default…
In this example, with the eyes in the right place, the left eye sees sides [4-1],[U-Y] of the object, the right eye sees sides [9-6],[Y-U].
Swapping the eyes around (but retaining their existing wiring to the brain, the left eye sees [4-1],[U-Y] (the right side of the object) and the right eye sees sides [9-6],[Y-U] (the left side).
My impression is that the brain would not realise that the eyes are in the wrong place, but would interpret the incoming sense data as an the view of the inside of a hollow object that looked like this:
Real easy way to test this: swap the images in a 3-D viewer. The resulting inside-out image is called pseudoscopic – the parts that should be closest to you seem farther away, and vice-versa. I see these kind of images when I look at some of those “Magic Eye” stereograms and I cross my eyes, instead of “looking through” the image. So instead of seeing, say, a pyramid popping out at me, I’ll see a pyramidal gouge taken out of the page.
I would imagine though, as Zoe says, that the perceptual system would adjust to fit round the new configuration, were it made permanent.
OK; another question; if I were to replace my biological eyes with (hypothetical) wide-angle cyber-eyes, one mounted on either side of my head (to give a 360[sup]o[/sup] field of view, like most birds have… would my brain adapt to the new sensory input and perceive it as a full wraparound view, or would I jusr perceive it as ‘in front’ of me, but distorted?
IIRC, that’s not exactly correct. It wasn’t the fact that they saw “right-side up” again, but that their brain eventually accepted “upside-down” as ‘normal’, and were able to function AS IF they saw everything “right-side up”.
I think the value of binocular vision in depth perception is real, but a bit over rated. Any time you’re not absolutely still, relative motion between nearby and more distant object gives a lot of depth information.
I had an eye injury once that required me to wear an eye patch for three weeks. I was surprised at how little trouble this gave me.
CalMeacham re: your daughter’s comment.
Ever seen the film THE OTHERS? Sounds like your daughter is…well…check out the film…
Sorry for the hijack.
Back to eye swapping. Before doing any surgical transplants, wouldn’t it be easier to simply make two low powered telescopes with flexible shafts? Then you could crisscross the lenses and look through to see what the difference would be.
My personal guess is that once you look at things half-ass, eyeball backwards, you will finally understand current US foreign policy.
