Naked Science Forum
Life Sciences => Physiology & Medicine => Topic started by: Eric A. Taylor on 06/11/2010 08:30:39
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In 1988 (I was 18 at the time) something happened to me that shook my faith in my own vision. I was driving to work and was almost there when I made a left (across oncoming traffic) The pick-up truck I was driving came to a very violent stop. I had no idea what had happened until I looked up and saw a wrecked car in front of me. I then realized I'd just crashed! I had turned left right in front of another driver. Fortunately no one was badly hurt (we were all wearing seat belts.)
I never saw the other car until after the crash. The other guy was going about 50 MPH and I was going about 20 MPH. We figured when I started the turn the other drive was around 50 feet from the intersection. Why didn't I see him?
I can understand not seeing things that a clearly not a threat to safety (like the cow 100 feet away from the side of the road) but this car was clearly a threat to my safety. I was belted but my head still hit the steering wheel so hard that it bent the wheel and a hammer in the back of the other guys pick-up had it's head broken off by the force of the impact.
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Hi Eric
One explanation could be the optic blind spot, we all have it and is thought to be a reasonable explanation why some drivers do say they literally did not see the other vehicle.
http://en.wikipedia.org/wiki/Blind_spot_(vision)
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Eric, vision is an active attention process. If you are not programmed to look for something you may not be able to see it very well. You were probably thinking of something else at the time and at 18 your driving habits may have still been developing. There is a test that you can take to check out how good your selective attention is. This can be difficult, but carefully try to keep track of the ball in this video-
Variola, You don't have a blind spot if both your eyes are normal and open because the spot in both eyes are within the region of binocular overlap and on opposite sides of the visual field. It is also quite small and small movements of the visual field, of the eye, or of the head would cause something to be visible if you were only using one eye. Take the blind spot test associated with your wiki link.
Steve
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Variola, You don't have a blind spot if both your eyes are normal and open because the spot in both eyes are within the region of binocular overlap and on opposite sides of the visual field. It is also quite small and small movements of the visual field, of the eye, or of the head would cause something to be visible if you were only using one eye. Take the blind spot test associated with your wiki link.
Indeed usually both eyes open is enough to counteract the blindspot in both eyes, however at certain angles, and particularly when you have other blindspots, such as the structure of a car, it is not enough to allow adequate information and processing for recognition of an object in the brain. As I recall there have been studies done in the past to test visual perception when driving. As for the blind spot test, I have taken it before thanks.
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Eric, vision is an active attention process. If you are not programmed to look for something you may not be able to see it very well. You were probably thinking of something else at the time and at 18 your driving habits may have still been developing. There is a test that you can take to check out how good your selective attention is. This can be difficult, but carefully try to keep track of the ball in this video-
Variola, You don't have a blind spot if both your eyes are normal and open because the spot in both eyes are within the region of binocular overlap and on opposite sides of the visual field. It is also quite small and small movements of the visual field, of the eye, or of the head would cause something to be visible if you were only using one eye. Take the blind spot test associated with your wiki link.
Steve
This is very true. It was payday and I was thinking about the weekend and the girl I was going out with that night (the date was postponed).
Here's a neat driving trick I learned. When driving at night on a dark road, when another car is coming at you close one eye (but only one eye, never both at the same time) this will shield one eye from the bright light and you will still be able to see after the other car goes by. (I'm assuming that you know enough to open the closed eye after the car has passed)
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Eric, vision is an active attention process. If you are not programmed to look for something you may not be able to see it very well. You were probably thinking of something else at the time and at 18 your driving habits may have still been developing. There is a test that you can take to check out how good your selective attention is. This can be difficult, but carefully try to keep track of the ball in this video-
Variola, You don't have a blind spot if both your eyes are normal and open because the spot in both eyes are within the region of binocular overlap and on opposite sides of the visual field. It is also quite small and small movements of the visual field, of the eye, or of the head would cause something to be visible if you were only using one eye. Take the blind spot test associated with your wiki link.
Steve
This is very true. It was payday and I was thinking about the weekend and the girl I was going out with that night (the date was postponed).
Here's a neat driving trick I learned. When driving at night on a dark road, when another car is coming at you close one eye (but only one eye, never both at the same time) this will shield one eye from the bright light and you will still be able to see after the other car goes by. (I'm assuming that you know enough to open the closed eye after the car has passed)
Also if you're blind in one eye this trick will not work as well
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Eric:
You are correct that the blind spot in one eye becomes relevant if the other eye is not available. However, it is also true that the spot is quite small and unlikely to overlap something important when the head and eye are free to move, and when one is moving within the visual field. If the blind spot was a significant detriment to vision it would have been corrected by evolution. On the other hand, selective attention has a huge effect on the accuracy of vision, and this is because it is very important from an evolutionary perspective. If you accurately counted the items in the youtube video test I linked, and watched the explanation, the power of selective attention is obvious.
Closing one eye to preserve dark adaptation against some oncoming clown who leaves his high beams on is a nifty idea. I am going to do it.
Steve