Lack of Motion Induced Blindness

[doc47]

My apologies if this has been covered before.

This subject came to me by email this morning and is excellent advice. It brings to mind all the reading I did as a young guy about WW II fighter pilots and how they were constantly moving their heads, swiveling their necks. One writer even commented that the reason they wore silk scarves was to prevent their necks from chafing on their flying jackets from all the constant motion.

 

Good info and demo. Lack of motion Induced Blindness was presented as a flying issue, but one can also miss things while riding, so, keep your heads and eyes moving. The below link is a great illustration of what was taught about scanning outside the cockpit. Military pilots are taught to scan the horizon for a short distance, stop momentarily, and repeat the process.

 

This is the most effective technique to locate other aircraft. It is emphasized repeatedly not to fix one's gaze for more than a couple of seconds on any single object. The instructors, some of whom are combat veterans with years of experience, instruct pilots to continually "keep your eyes moving and head on a swivel" because this is the best way to survive, not only in combat, but from peacetime hazards (like a midair collision) as well.

 

The most dangerous target is the one that has NO apparent motion. This is the one you will hit without evasive action and also the one you will NOT see as presented below.

 

 

Link

 

[Rougarou]

The technique is not only taught to pilots, but to grunts on the ground, especially for night ops. Staring into the darkness will net you less visible objects. The constant scanning, you pick up on "things" that go boom in the night. Another that is taught is to off-set your sight as when you do pick up an object in the dark with your sight, look to the left or right of it and you will make out the object in a more clear fashion.

[doc47]

Our nervous systems are hard-wired to detect motion. Stationary objects don't attract attention (unless it's that parked Volkswagen I'm about to hit!).

 

(Nice-looking women are, of course, an exception, even if motionless.)

 

The part of the retina that we use all the time, in the center of our vision, is loaded with cone cells. These are fine-grained and register color. The surrounding area has rod-cells. These transmit only black-white images to the brain but are much more sensitive to low levels of light. Hence, looking slightly away from the object at night allows the image to fall on the rod-cells. Color is no use in low-light situations. The rod-cells, however, can't define an image as well as cone cells. The image will appear more hazy/blurry.

 

Probably more than anybody needed to know.....

[Horse]

The most dangerous target is the one that has NO apparent motion. This is the one you will hit without evasive action

 

There's an effect known as 'constant bearing (or heading), which shows that if two vehicles are travelling on different paths, but each is on a constant heading when viewed from the other, they will hit. Unfortunately, a constant heading is the worst for obscuration (muck on a driver's screen, blind spot in the eye, hidden by 'A' pillar, etc.

 

Plus, being a 'fixed point' against a background is really bad from the conspicuity point of view - a point used by some creatures when hunting - eg dragonflies will move against the background as their prey moves, so they remain 'fixed'!

 

So, to make yourself more visible when approaching junctions . . .

 

 

A couple of variations on a theme.

 

The first is 'Z Line':

 

http://the-ride-info.blogspot.com/2008/08/z-line-introduction.html

http://the-ride-info.blogspot.com/2008/08/z-line-2-limits-on-vision.html

http://the-ride-info.blogspot.com/2008/08/z-line-3-prepared-for-action.html

http://the-ride-info.blogspot.com/2008/08/z-line-4-ouellet.html

http://the-ride-info.blogspot.com/2008/08/z-line-4-how-it-helps.html

 

The second, for the same circumstance, is weaving:

 

 

 

I prefer the 'Z Line' alternative as it movesyou away from the potentially encroaching vehicle - giving more time for you to react - and means that if you do have to react then the bike is straight and upright for the 'final approach'.

 

 

Finally:

 

http://www.youtube.com/watch?v=B-Lav2IOsjE

 

May I suggest that those of a gentle disposition, or in 'work' or 'home with small children' situation, may wish to mute the sound

[4wheeldog]

The silk scarves originated in WWI. They were an used in association with goggles, and total loss engine oiling. The scarf was handy to remove the oil from the goggles, thus restoring some semblance of vision.

 

Keeping one's head on a swivel is good advice always....Even when walking in urban environs. Only when safely in your own house should you relent.

 

[Dave_zoom_zoom]

Thanks Doc

 

"Good tip"!

 

Who knew? Not I!

 

Thank You

[ESokoloff]

 

So, to make yourself more visible when approaching junctions . . .

 

 

 

The second, for the same circumstance, is weaving:

 

 

I came up with the weaving technique when I returned to riding after t-boning a motorist that pulled out on me.

[Rocer]

Hi Doc, the concept of constant scanning is (still) used in the training of private / recreational pilots. It's also used in many driver's ed programs as part of their defensive driving techniques.

 

One of my best driving instructors used to say that if you look in your rearview mirror and are surprised to see a car there or anywhere in your visual periphery then you weren't scanning frequently enough. There's nothing like the feeling of vulnerability when riding a moto to accentuate the need to constantly scan. Thanks for the reminder. Maybe we should buy stock in the silk scarf industry.

[upflying]

Hi Doc, the concept of constant scanning is (still) used in the training of private / recreational pilots. It's also used in many driver's ed programs as part of their defensive driving techniques.

 

One of my best driving instructors used to say that if you look in your rearview mirror and are surprised to see a car there or anywhere in your visual periphery then you weren't scanning frequently enough. There's nothing like the feeling of vulnerability when riding a moto to accentuate the need to constantly scan. Thanks for the reminder. Maybe we should buy stock in the silk scarf industry.

Very true about scanning, also known as situational awareness. If you are doing it correctly there is no need to look over your shoulder for vehicles prior to a lane change. You know from scanning whether there is a vehicle there or not.

[Paul Mihalka]

"If you are doing it correctly there is no need to look over your shoulder for vehicles prior to a lane change. You know from scanning whether there is a vehicle there or not."

 

Correct, but I still look over my shoulder - just in case...

[SteveHebert]

My apologies if this has been covered before.

This subject came to me by email this morning and is excellent advice. It brings to mind all the reading I did as a young guy about WW II fighter pilots and how they were constantly moving their heads, swiveling their necks. One writer even commented that the reason they wore silk scarves was to prevent their necks from chafing on their flying jackets from all the constant motion.

 

Good info and demo. Lack of motion Induced Blindness was presented as a flying issue, but one can also miss things while riding, so, keep your heads and eyes moving. The below link is a great illustration of what was taught about scanning outside the cockpit. Military pilots are taught to scan the horizon for a short distance, stop momentarily, and repeat the process.

 

This is the most effective technique to locate other aircraft. It is emphasized repeatedly not to fix one's gaze for more than a couple of seconds on any single object. The instructors, some of whom are combat veterans with years of experience, instruct pilots to continually "keep your eyes moving and head on a swivel" because this is the best way to survive, not only in combat, but from peacetime hazards (like a midair collision) as well.

 

The most dangerous target is the one that has NO apparent motion. This is the one you will hit without evasive action and also the one you will NOT see as presented below.

 

 

Link

 

Good points here Doc and a topic that the US Army beats to death in flight school.

 

The two blind spots that we as humans encounter are:

 

1. The physiological or so called "day" blind spot which is caused by the lack of all photoreceptive cells in the area of the retina where the optic nerve is attached. This area is roughly 5.5-7.5 degrees wide and is offset 15 degrees from the center of the field of vision. Becasuse we use binocular vision, each eye compensates for the other and this is rarely noticed. The issue is when we stare straight ahead and do not scan with our eyes or move our head. Objects in the periphery coming into the field of view are not detected until they are in the central viewing area. Obviously, the farther away an object is, the larger it can be and go unnoticed.

 

2. The night blind spot is in addition to the physiological blind spot and should not be confused with it. This is caused by the lack of rod cells in the central viewing area of the eyeball (fovea centralis), and covers an area roughly 5-10 degrees wide. The cells in the fovea centralis are called cone cells and are responsible for color vision, etc. They instantly are able to see if the level of light is bright enough. Once the light level decreases, humans become blind in the central viewing area and rely on the rod cells in the fovea centralis. Those cells require some time to build up a level of rhodopsin, the chemical which allows us to detect motion. There is no color vision in this area of the peripheral retina. It takes approximately 30-45 minutes to dark adapt to the best level that we can achieve. Many factors affect that such as exposure to bright light during the day. Your starting level can be very different from one another in that regard. But what ever the case, the rods detect movement only. If an object does not move and you stare at it, it will disolve or dissapear from the central viewing area. We learn to "see" stationary objects by either scanning or using off center vision, looking 10 degrees to the sides or above/below every few seconds. So if an object is not moving to stimulate the rod cells, we induce movement by turning our heads or shifting our eyes every few seconds.

 

I hope that helps a bit.....

[4wheeldog]

 

So, to make yourself more visible when approaching junctions . . .

 

 

 

The second, for the same circumstance, is weaving:

 

 

I came up with the weaving technique when I returned to riding after t-boning a motorist that pulled out on me.

 

I got pulled over one fine NM Sunday for doing just that........Cop insisted I was going to fall down, if I continued to do that. He told me he was going to give me a ticket for "Failure to maintain control". He got called away on something more important.......At least that is what he told me, after he asked how long I had been riding, and I told him I was really looking forward to seeing him in court.

[doc47]

Steve and 4wheel,

 

Good input. Thanks. Steve, I hadn't thought about the retinal- disc-created blind spot. Good point.

And a good video. But, why can't those Limeys learn to drive on the right side of the road????? No wonder they have accidents!

[Skywagon]

don't confuse scanning with sweep. As you scan you need to hold your position for about 2 seconds about every 7-10 degrees. If you just sweep from left to right, up to down, or their inverse, you are highly likely to miss conflicting traffic.

 

 

[Horse]

And a good video. But, why can't those Limeys learn to drive on the right side of the road????? No wonder they have accidents!

 

We do, sometimes, and call it 'off-siding' - but it's hotly debated in training circles as ther is high potential for 'cluster___'