h a l f b a k e r yExperiencing technical difficulties since 1999
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I'm not talking about staring at something in particular. Rather, that gazing sensation after looking somewhere for a short while with no concentration on what's in the center. It happens much more quickly when tired, and is almost unavoidable when looking out at a large, distant area. It's a fairly
abrupt change. Vision goes from strongly favoring what's in the middle to the exclusion of the edges to an even view of the entire field. The switch can be controlled, even, with a little concentration.
The optic nerve is pretty low bandwidth. Less than 10Mbps per eye according to most sources. There are far more rods and cones than are able to transmit back simultaneously. It's also evolutionarily much less expensive to grow receptors than it is to wire them each all the way back to the brain.
I propose that the sensation of staring off in the distance is a mode switch. When concentrating on the center of one's view, a signal tells the eye to send a lot of data from the center and very little from the edges. When an entire scene needs to be taken in, to search for motion, for example, the eye allocates the bandwidth used to make the center extra sharp to evenly cover the entire field of one's view. Either way, the same total bandwidth is used.
Alternatively, all pixels could be sending data back at a very low refresh rate, and the gaze switch is entirely in the brain's focus on different sets of data. Either way, something doesn't have the capacity to take in and combine data from all available photoreceptors, and switching is occurring, either at the software or hardware level.
(This isn't strictly an invention, but I also don't think it falls under theory, which would qualify it for deletion. If you read it in reverse, it becomes a brain implant-style invention for switching viewing modes that we actually already have pre-installed but goes unnoticed. Delete if desired, though.)
Magnetoencephalography
http://en.wikipedia...netoencephalography
[bungston, Mar 15 2010]
Lawnmower effect but odder.
http://www.spiegl.o...r/flash/wonker.html
[MaxwellBuchanan, Mar 16 2010]
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Gazing at this so-called idea causes a similar sensation [dd]. Your lawnmower should have a key or a switch to turn it off, failing which stand up - there should be an auto-cut-out in the seat. |
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//After a couple of hours on a ride-on lawnmower & focussing ahead at a constant distance, stopping & looking up into a sky with clouds in it produces quite an amazing effect of the clouds receding away from me// |
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I have experienced this but always in conjunction with long periods of vibration such as riding a lawn mower or operating a hammer drill. Also various other circumstances with varying focal length attentions. |
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As for the idea, this doesn't make much sense in relation to my limited knowledge of evolution or the workings of vision. My guess is what you are experiencing is your consciousness filtering out data to simplify the experience. My guess would be that the other data is there and would be presented if the processing systems felt it was important. i.e. HUNGRY TIGER! FLEE! |
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Again this is all Discovery Channel knowledge so correct me if I am wrong, but the eye isn't sending back pixels, it is sending back something like edge vectors. i.e. if you are a computer nerd like me, more like Postscript than BMPs. |
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The lawnmower thing is different: it is the same thing as looking out the window of a taxiing airplane then feeling everything is moving when you come to a halt. |
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This would be hard to test because bandwidth prioritization is probably very evolutionarily flexible as the authors proposes. Test animals might not do it like we do. It would be hard to noninvasively test this in humans. |
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But not impossible: maybe it could be done with mri magnetoencephalography? |
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I think this is a theory, to be honest. I also suspect that
the change is not in the data being sent from the eye, but
in the attention given to it by the visual parts of the brain.
(I'm not aware of innervation *from* the brain *to* the
retina, though there might be such a thing). If it *is* an
attention thing, it might be simply that the visual cortex
wants a rest, or perhaps it enhances our ability to detect
movement or significant objects in a wide visual field by
concentrating less on the centre. |
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As for the lawnmower/plane/etc illusion (where stationary
things appear to move in the opposite direction to
previous movement), there are lots of similar illusions (try
the link), all involving "contrast" (movement/stillness,
light/darkness, opposing colours etc). Many of them seem
paradoxical, but they arise from the fact that the many
aspects of a scene (shape, colour, movement, edges,
brightness, colour) are actually processed independently
before being merged into what we think of as an
integrated image. So, for example, if you saturate the
"movement" receptors and then look at something still,
you get a perception of movement in the opposite
direction, even though the positions of objects appear not
to change. It is what neuro-optic psychologists call
"fucking weird". |
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