Saturday, August 29, 2015

Motion Induced Blindness


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 driver's 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. The reason is, 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.

When I was in college, I got a Summer job driving busses for Greyhound.  I recall that there were six of us hired, and we had to go through a driver school for several weeks to learn how to drive a big bus with manual transmission and a long turning radius. Our teacher, a full-time driver, taught us several 'tricks of the trade' to keep ourselves alert and awake on those long haul trips.  One thing he drilled into us was to keep our eyes moving at all times and never focus on one point or distance. One way to do that was to do a mirror check every minute. That meant checking both the right and left mirrors.  (Busses and large trucks don't have 'rear-view mirrors like cars do on the windshield.)

I incorporated most of what Tim taught me way back fifty years ago, and I still drive that way today in my car, except that I do have the rear-view mirror to check along with the other two.  It has kept me out of harm for all those years.

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.

Don't believe it?  Just watch the yellow dots for some time to ensure that they don't go anywhere!  https://www.youtube.com/watch?v=Hfrb94mKCJw

Another great pointer that Tim gave was to "think ahead."  When you see a slower moving vehicle up ahead in your lane and you know that you will have to pass it, don't wait until you are within 100 yards or less to pull out.  Check your mirrors and start your pass as soon as you can. 
 
You probably have seen that sign on the back of 18-wheelers that says "If you can't see my mirrors, I can't see you".  It's there for a reason.  Don't get so close to trucks - which are usually held to a speed limit 10 miles slower than passenger vehicles - that you cannot see the side mirrors.  You put yourself and the trucker in danger when you do that.

I have never been able to teach my wife the above lesson, and she constantly gets up behind slower vehicles waiting to pull out while traffic from behind continues to pass us and the slowpoke.  I've tried to tell her to pull out as soon as she knows she needs to pass, but she insists on staying in the lane until we become part of the slow-moving traffic.  Too many prompts and I become the backseat driver.  Well, maybe I can teach someone out there to relieve my frustration.