Why does our brain invert the image received from our eyes?

Pythagorean

Not at all. We're talking about why there's a preference. The evolutionary development is a different discussion.

Pythagorean

Though, I think the developmental story would still be about computation and efficiency (and efficiency pertains to availability), just not among neurons alone, so much as genetic code and protein signaling and the whole complicated set of processes involved in life.

madness

I still haven't worked out why any configuration would require more computation than another. I don't think there is any "right way up" and "upside down" as Dave wrote, just conventions that we've grown used to. Even if our proprioception was inverted with respect to our vision, we would just experience the world like looking in a mirror and that would seem normal to us.

russ_watters

True.... another useful effect of this I can see is that it acts as as a sort of built-in image stabilization. Try bobbing your head from side to side (not too many times!) and see how the image stays pretty stable.

Evo

Try standing on your head for 8 hours (don't really do this) and tell me that there is no up or down. For example, if our brain didn't correct the image and we saw an uncorrected upside down and reversed image, the sky would be at the bottom and the ground would be at the top.

Pythagorean

Try watching tv lsideways or upside down. In the time before you adapt, you might find it somewhat laborious to interpret the screen sideways.

To continue withe the my other analogy, try using a map that's backwards to navigate. It requires an extra step to transform from one coordinate system to another.

Even if up and down are just conventions, we still want up on our map to match up in the world, however we define it (wrt gravity most commonly).

zomgwtf

I'm failing to make sense of what many people here are claiming. If we perceived naturally the inverted image it would not make a difference to 'up-down' orientation. It would be normal for us to see that way and this way would still be this way even if to our present normal vision it would be backwards. I do not think there would be any difference in efficiencies... this is just the way we've evolved. If we evolved seeing the world inverted it wouldn't make the slightest difference.

It seems people seem to be thinking that if we pereived things as being inverted we would have to think about what we're seeing in order to know what's going on... what they fail to accoutn for though is that our brains would be acustomed to the 'invertedness' of our vision and it would just be normal. If I wanted to go to the door that is on my left right now my brain would still perceive where the door is relative to my position and I would be able to move as such to get to the door.

zomgwtf

This analogy isn't too great I'd say. If you were to stand on your head for 8 hours you wouldn't be inverting your perception, it's completely different. Your perception is still normal but you are upside down relative to your normal position.

If your vision were to truly be inverted it would be your normal position that everything else is relative to.

Monique

Exactly, that is also my interpretation.

zomgwtf

So you're going to argue that with our normal present perception if we were to try and force it to work differently it would require extra work and you think that's a good argument?
See above.

Some how if we invert our vision our brain will no longer be able to determine what is above us and what is below us RELATIVE to us?

russ_watters

Try examining the issue from the opposite direction: Our brains are making a correction (actually, quite a lot of them from the examples given). If this correction was unnecessary, then there should have been no evolutionary pressure to make our brains wire themselves that way.

zomgwtf

Corrections? I thought I already stated that if we just perceived the world as inverted everything would be inverted and perceived as normal... there's really no 'correction' here... If we still knew 'left-right-up-down' in such a world those directions would still travel with us to our new perceptions... they wouldn't be the same directions though if you looked at one from the other perspective. They'd be inverted, of course.

It's hard to explain it but the directions are actually relative to us... there is no objective 'up' direction to perceptions. The only thing objective about up is that it is above us...

And evolutionary pressure? I assume you are trying to say that all things that happen in biology due to evolution must be a 'good' or 'positive' change? Or that the changes are for the benefit of the organisms? This may very well be true, in regard to our vision, but I do not think any of the reasons listed about computational advantage or efficiencies are involved at all.

russ_watters

Are you saying that you don't notice a difference in the way the world looks when you flip yourself upside down nor do you notice that after a while that difference goes away?

Our brains do manipulate up and down in the processing of our vision.

The way I first read your objection was that you believe that this correction was unnecessary: that if the correction wasn't made we'd still be able to learn to coordinate motion just as easily as we can with this correction applied.

zomgwtf

Yeah relative to what is already normal.. not relative to any objective standard of direction.

If it was normal from the beginning to be 'inverted' then that would mean the new inverted is the old normal. Maybe then we would be thinking about how weird and crazy it would feel to live in a world where we pereived things as inverted (normal to us now) but as far as I can see things look pretty normal!!!

EDIT: In response to the added bit, that is exactly my objection with the exception about 'learn to co-ordinate motion'. We wouldn't 'learn' anything it would just be normal, w would do it the same way we do now... because everything we perceive is always relative to us.

Monique

Actually, the example you've given (about watching television at an angle) is caused by the brain interpreting the rotation of your head: it takes into account the signal from the vestibular system in your ear. This is to correct for the movements that your head makes during every day life. Chickens have their own system to stabilize their vision, watch this video: http://www.youtube.com/watch?v=_dPlkFPowCc

russ_watters

...btw, I thought of a good reason why the images need to be corrected: binocular vision. If the image orientation wasn't corrected, then our depth perception and even the overlay of the two fields of view themselves wouldn't work.

russ_watters

Yes, I understand that. It takes an input from our internal gyro and uses it to correct the orientation of the picture. I suspect it also does the same thing when we stand on our head and after a while the image flips. So that fits just fine with my point: the brain is making a correction. If this correction was unnecessary, why bother?