Quote from: ginoe on August 08, 2005, 11:45:59 AM
how about this...
motion camouflage
An article in the March issue of the UK magazine Bike added a bit to the understanding of why cars pull out in front of motorcycles. Research on how certain insects attact prey was applied to the SMIDSY crash (sorry mate, I didn't see you).
When attacking, a dragonfly stays directly in the line of sight between its potential dinner and a fixed point in the distance. If dinner moves, the dragonfly alters its path just enough to stay on that line of sight. It doesn't swoop out to "lead" its victim. This tactic has the effect of keeping the dragonfly at the same point in the prey's visual field. Because the prey sees no change in the big picture, it is unaware of the impending attack. This is called motion camouflage.
Motion is difficult to perceive when it is directly along the line of sight. Because the object is stationary relative to the background, an observer doesn't see a change in the overall image and thus isn't cued to the presence of a moving object. Though the object increases in apparent size as it nears, the change goes unnoticed at first--moving from 1000ft distant to 900ft may not affect the image enough trigger a response. A motorcycle is particularly susceptible to motion camouflage because its cross-section area as seen by an observer is much less than that of a larger vehicle.
But as the object gets closer, apparent size increases more rapidly. At constant speed, an approaching object takes the same time to move from 200ft to 100ft as it did from 1000ft to 900ft, but the apparent size increase is greater. Eventually the object seems to grow suddenly in size, and the motion camouflage is broken. This is called the looming effect. According to the Bike article, when an observer is startled by the looming effect, he may freeze in his tracks. If the observer is an oncoming left-turner, he may stop in the middle of the intersection, making a bad situation even worse.
Duncan MacKillop, the riding instructor who related motion camouflage to motorcycling, suggests that diverging from the direct line of sight will break the motion camouflage and get the observer's attention. For example, a driver stopped at a cross-street on your right will be looking left at a slight angle to the path of the road. If you stay to the left of your lane, you will diverge from his line of sight, making yourself more noticeable. But if you're veering right (say, moving from the left to the right lane) you'll be moving along the crossing driver's line of sight, helping to hide your motion against the background.
MacKillop recommends: "I observed a smooth, gentle, single, zig-zag motion, at any point along the line, created a rapid edge movement against the background and destroyed the motion camouflage. Drivers' eyes snapped towards me and they froze the movement I swept left to right and back again."
I read this post earlier, then got tied up with a lot of nonsense and didn't have time to reply until now; thanks for posting this. Though many seem to have read it already (57 times as I type this), I didn't want you to feel your efforts weren't appreciated.
If you've ever attended a class on patrol tactics (I don't know your MOS), you've probably been advised not to look straight ahead when you're trying to detect motion; as this article demonstrates, it is much easier to detect motion from an angle, which has been taught in military tactics for centuries.
Baseball pitchers who throw fastballs on a (relatively) flat trajectory (such as Nolan Ryan and Roger Clemens in their younger days, for example) use the "looming effect" to their advantage. Even umpires can have trouble seeing the ball in flight, and they are facing the pitcher head-on. That is why some hitters have made comments to umpires (and others) about how a certain pitch "sounded" low, or outside, or whatever, because they weren't able to follow the trajectory of the ball after it left the pitcher's hand. The looming effect strikes again...
this was the first i'd heard of the "looming affect"
My MOS was in aviation. I got out awhile back. My reenlistment came up in Iraq.
I gave them the big :flipoff:
very interesting, and it makes sense. Who knew dragonflies were so clever?
-M
is it true Dragon fly's only live for a 24hr period? as the actual fly?
Quote from: 3imo on April 12, 2006, 07:35:58 AM
is it true Dragon fly's only live for a 24hr period? as the actual fly?
a lot of sources claimed to be so but they actually live upto 2 months
house fly has upto 30-day lifespan
Quote from: 3imo on April 12, 2006, 07:35:58 AM
is it true Dragon fly's only live for a 24hr period? as the actual fly?
You are mixing that up with mayflies. And those have a lifespan of a few days as well.
If the Dragonfly were so short lived it would not bother with hunting for prey. The short lived insects don't busy themselves with eating, just with procreation. Now that's a life! The only thing on your mind is sex!
But as with most insects, the larva stadium is much more long-lived in the dragonflies (about 2 years, IIRC). Still, that's nothing compared to the periodic cicada. (17 years)
Quote from: MarkusN on April 12, 2006, 07:55:48 AMThe only thing on your mind is sex!
I don't see how thats much different from most people I know....
Quote from: Unnamed on April 12, 2006, 01:04:47 PM
Quote from: MarkusN on April 12, 2006, 07:55:48 AMThe only thing on your mind is sex!
I don't see how thats much different from most people I know....
you say it like its a bad thing
Oh not at all... I certainly have my days ;)
Enough of the boner talk already.
Seriously though, that's really interesting stuff. Good find!
great article. I also once read an article debunking the idea that bright colors will make you more visible. It was directed at bicyclists and I think it was in Scientific America or something like that. That was an eye opener too and applies to the idea of using a bright helmet for motorcycles.
thanks for sharing that with us.
Quote from: pantablo on April 12, 2006, 03:33:49 PM
great article. I also once read an article debunking the idea that bright colors will make you more visible. It was directed at bicyclists and I think it was in Scientific America or something like that. That was an eye opener too and applies to the idea of using a bright helmet for motorcycles.
thanks for sharing that with us.
Bright colours were no good? Please explain
it was along the same lines of that article. If I recall, it had to do with your mind seeing an anomoly in the visual field (your bright colors) but filling it in with the surrounding visual to compensate for what it considers a "mistake" for lack of better terminology. I wish I had saved it-actually I did but I couldnt find it. Its come up before and the article would help support my position. I was shocked by it and it goes against common sense, but was backed up with experiments.
The visual cortex (part of the brain that handles vision) is like a sub processor or a graphics card if you want to use a electronic computer analogy. It handles control of the eyes and does pattern recognition and depth perception among other things and then "hands" the final visual picture to the contiouse <sp> mind.
Part of that is that it is hard wired to notice and track motion (change in the image) first before anything else. Thats why this and phenomenon like optical illusions work...
I just assume that other drivers either; don't see me, or if they do, are attempting to run me over on purpose. :mad: And ride accordingly. :flipoff:
I found that the annoying green color of my old jacket changed things a little... But, it was very little...
Although, it helped my friends and neighbors recognize and find me when I was riding. :laugh:
Do you suppose reflective things like those Halo straps for helmets fall into the same catagory, or would they be more noticable?
I say wear bright clothes until someone posts a decent reference about it.
I'd hate someone to go with black just cause they read here that it dont matter.
If its true then fine...prove it.
YAY!!!! colors :thumb:
I think the point is that colors don't make a driver more likely to notice you, but might make you stand out more for someone that notices you... At least that's what it seemed like to me... Drivers that don't look wouldn't see you if you had a 1,000,000 candle power light shining on you whenever you road.
When I had my bright green jacket, I'd notice people doing a double take... They'd see me in their mirror or peripheral and they'd get a look like, "WHAT THE HELL IS THAT?!?!?" and really look at me. But, I still had lots of people trying to drive through me.
I think it also has a lot to do with the "impending threat" theory... You're a little moto... Like you'd do any damage. :?
I definitely need to see some "proof" that bright colors don't make you more noticeable. I for one see the dudes wearing the white full face helmets from a mile away!
jeff
The Hurt Report found that bright colours significantly reduced involvements in accidents.
See point 14 at http://www.clarity.net/~adam/hurt-report.html
I, for one, am wearing bright colours, even if I look severely fashion-challenged.
Mike
I purchased myself a saftey vest like this for night / bad weather riding and have found in these conditions it has helped me stand out and be seen.
ITs 2nd benefit is that it makes me look like a police officer (work cover requires them to wear a vest), so cars naturally slow down around me.
(http://media.msanet.com/NA/USA/MSASafetyWorks/BodyFirstAid/SafetyVests/ClassIISafetyVest/ANSI-Class-II-Safety-Vest.jpg)
Cost me $15 AUS and I purchased it to fit over my jacket.
Quote from: 3imo on April 13, 2006, 12:30:51 PM
I say wear bright clothes until someone posts a decent reference about it.
I'd hate someone to go with black just cause they read here that it dont matter.
If its true then fine...prove it.
YAY!!!! colors :thumb:
I'm going to look it up, but it follows the theory of the eye's blind spot. Bet you didnt know your brain was its own little photoshop, did you. here's an explanation of the eye's blind spot and how the brain "completes" the picture, including a little experiment you can do.
http://ourworld.compuserve.com/homepages/cuius/idle/percept/blindspot.htm
I'm still looking for the exact article I read previously though, stay tuned.
"lateral inhibition in the retina"
closer to what I am talking about:
http://serendip.brynmawr.edu/bb/latinhib.html
there's this famous experiment, which resulted in people not seeing a man dressed as a gorilla beating his chest (50% didnt see him!):http://www.sciamdigital.com/index.cfm?fa=Products.ViewIssuePreview&ARTICLEID_CHAR=E7827E04-2B35-221B-6548C570D8D033D6
QuoteIn fact, 50 percent of subjects in this remarkable experiment by Daniel J. Simons of the University of Illinois and Christopher F. Chabris of Harvard University did not see the gorilla, even when asked if they noticed anything unusual (see their paper "Gorillas in Our Midst" at http://viscog.beckman.uiuc.edu/djs_ lab/
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HA! this is the phenomenon I am referring to-INATTENTIONAL BLINDNESS http://www.visualexpert.com/Resources/inattentionalblindness.html
QuoteWe see objects, not because of their absolute brightness, but by their contrast with the background. When there is higher contrast, objects are more conspicuous. For example, black cars are involved in many more accidents, presumably because they harder to notice at night. We also are more likely to notice objects which are large and which move or flicker. That's why school busses, police cars, ambulances, railroad crossings and so on all use flickering light. Recent research has shown , however, factors such as bright colors, movement and flicker do not ensure conspicuity. For example, Britain experienced a rash of accidents where drivers struck police cars parked on road shoulders. In order to reduce the accidents, the entire police car rears were painted the "highly conspicuous" chevron pattern as shown in the figure. Although the cars might now seem conspicuous, the rate of these accidents actually increased.
ALSO FROM SAME LINK:
Quote3. Expectation
Past experience exerts a strong control on attention because it teaches us what is and isn't relevant. For example, think about your breathing. You can now sense the movement of your chest. Of course, the movement was always there but you were inattentionally blind to it because it is highly uninformative. Nothing new ever happens, so attention filters away the sensation to conserve mental processing.
Expectation has a powerful effect on our ability to see and to notice. When my wife and I go to the mall, we sometimes separate to perform errands. When I go to look for her, I usually recall her coat and search for someone wearing he right color. At first, I did this unconsciously, but after I while I realized that I was adopting an attentional set on purpose. Color blobs (a coat) are far easier to scan and search than are the finer details of facial feature. This strategy usually works, but once in a while I'll have forgotten which coat she wore that day and expect to see the wrong color. On those occasions, I've walked right by her, completely blind to the other features, all highly familiar, which should have attracted attention to my wife.
Errors often occur when there is a new and unusual combination of circumstances in a highly familiar circumstance. The driver who hit the bicyclist had pulled into the same driveway every workday for a year and had never seen anyone. She had unconsciously learned that there wasn't anything important to see down the sidewalk. The submarine captain had learned that if there were no blips on the sonar, then there should be no ships in view. The nurse was used to picking out the same size and shape bottle that contained a different drug.
Thanks for the links, I like the one with the blind spot finder. Pretty neat.
I don't doubt any of what those papers and articles say. But I think it may be inappropriate to take the conclusions or assertions they support and extend that to other issues they're not directly addressing. As was previously stated, the Hurt report suggested decreased incidence of collisions for brightly dressed riders. If the research in those links was 100% relevant to our problem this would not be the case, right?
Perhaps I'm oversimplifying, but consider camoflage. Our soldiers (or hunters and ninjas for that matter) wear it so they blend in with their surroundings, making them less noticeable. The opposite, that if you stand out from your surroundings you are more noticeable, has to be true. This explains the weird bright orange hunters use - to animals it doesn't look so bright, but to other hunters it does! Therefore, riding with your headlight on and wearing bright clothes should make you more noticeable, and therefore less likely to be hit.
I think these articles talk to the reasons we can still be hit, regardless of what we're wearing or doing, but I'm not sure they point to a conclusion that bright gear won't help.
jeff
Quote
Errors often occur when there is a new and unusual combination of circumstances in a highly familiar circumstance. The driver who hit the bicyclist had pulled into the same driveway every workday for a year and had never seen anyone. She had unconsciously learned that there wasn't anything important to see down the sidewalk. The submarine captain had learned that if there were no blips on the sonar, then there should be no ships in view. The nurse was used to picking out the same size and shape bottle that contained a different drug.
Let me toot my horn again against installing loud horns on a motorcycle. Put in a big horn might scare the crap out of the dozing grandma, but she will look out for a big truck and miss a tiny motorcycle. The only solution is to ride defensively, which is the price we all pay for being motorcyclists.
Cheers,
e.
Thanks Pablo, I will share this with my Motorcycle buddys around town.
although I think Jeff is 100% right, it's still a good thing to know and consider on the road.
Quote from: Jeff P on April 14, 2006, 04:03:21 AM
I think these articles talk to the reasons we can still be hit, regardless of what we're wearing or doing, but I'm not sure they point to a conclusion that bright gear won't help.
jeff
The articles don't really conclude bright colours make you less likely to be seen.
Just that normal driver behaviour usually results in drivers going into autopilot and not changing their driving style, like checking their mirrors just that little bit more before changing lanes, or looking left/right and actually being prepared to stop at intersections.
I know as a car driver, I used to make an effort to look right down a low traffic road before pulling out, but the one time a car was actually coming the other way (after months on months of never seeing a car) I realised that even though I looked right, I was not actually expecting to stop. My late reaction time meant there could have been an accident if I hadn't seen the other car until a fraction of a second later.
If the bright clothing allows you to be seen 100th of a second earlier by drivers, thats a big :thumb: in my book.
Regarding camouflage - I think it is more important to wear a solid color, thus appearing as a larger more singular object, than multiple colors that break up against a background like camouflage. A solid white, or black, helmet; all black leathers...