Motion Induced Blindness —how your eyes can play tricks
In a motor accident, wherein a speeding car hits a slower moving vehicle coming from the side, the speeding car drivers often swear that they just didn’t see the vehicle coming from the left or right. Well, they aren’t lying. They really don’t see the vehicle coming from the side, in spite of broad daylight. This phenomenon on the car drivers’ part is known as “Motion Induced Blindness”. It is definitely frightening.
Once airborne, pilots are taught to alternate their gaze between scanning the horizon and scanning their instrument panel, and never to fix their gaze for more than a couple of seconds on any single object. They are taught to continually keep their heads on a swivel and their eyes always moving. Because, if you fix your gaze on one object long enough while you yourself are in motion, your peripheral vision goes blind. Till about three decades ago, this “heads on swivel & eyes moving” technique was the only way to spot other aircraft in the skies around. Now-a-days they have on-board radars, but the old technique still holds good.
Let me give you a small demonstration of motion induced blindness. Just click on the link below. You will see a revolving array of blue crosses on a black background. There is a flashing green dot in the center and three fixed yellow dots around it. If you fix your gaze on the green dot for more than a few seconds, the yellow dots will disappear at random, either singly, or in pairs, or all three together. In reality, the yellow dots are always there. Just watch the yellow dots for some time to ensure that they don’t go anywhere!
So, if you are driving at a high speed on a highway and if you fix your gaze on the road straight ahead, you will not see a car, a scooter, a buggy, a bicycle, a buffalo or even a human being approaching from the side.
Now reverse the picture. If you are crossing a road on foot and you see a speeding car approaching, there’s a 90% chance that the driver isn’t seeing you, because his/her peripheral vision may be blind! And you may be in that blind zone.