Friday, February 5, 2016

The 'Death Farm': Some Thoughts on Obstacle Blindness

The country roads in County Derry are notoriously bendy. But one bend near the town of Limavady has an especially bad reputation. Although neither as sharp nor as awkwardly cambered as some of the others, it is said to have claimed the most lives. And so continuing on the theme of the senses from the previous post, let me tell you about the Death Farm.

In fairness this farm is a lush, picturesque enterprise, set amidst much Queens Lace and soothing mountain views. But it is situated on a bend. And the tall, curved stone wall of the farm's main structure sits in such a way as to turn invisible when perceived from certain angles.

I first experienced this phenomenon just shortly after having moved to the area. I was cycling to my then-home nearby and approached the bend from the west for the very first time. The green roof blended so perfectly with the trees and the mountain behind it, and the gray stone wall with the road in front, that I felt myself compelled to cycle straight ahead - along the "road" and toward the "trees" instead of turning into the bend. The illusion was remarkable. My mind knew there was a bend, not least because of the prominent warning arrows. And yet my eyes saw a straight road ahead. It was like that early X-Files episode about mind control, where the guy keeps saying "cerulean blue" in a soothing tone of voice until the driver of the police car crashes into a truck, convinced it's an expanse of sky he is heading toward.

I've been told this farm has a history of vehicles smashing into it - every year or two, like clockwork. Whether this is truth or local lore I cannot say for certain (an attempted search for evidence of traffic deaths on this road has proved unsuccessful). But my own experience certainly makes it seem plausible - I can especially see how drivers passing through and unfamiliar with this road might fall victim. Even today, with the trees standing bare and the green of the mountain reduced in the dead of winter, the illusion was strong.

It made me think of visibility. And namely, of other instances of "obstacle blindness." How many times have we watched someone walk into a door or a window right in front of them, or done it ourselves? Tripped over a large and obvious object right under our nose? Bumped into the person next to us, whether on foot or two wheels?

Along a woodsy cycle path in Belfast, they've recently installed these waist-high poles straight through the centre of the lane - presumably to prevent cars from entering. Seeing shots of this on twitter made me wince for the people of that fine city. Because, you see, similar contraptions can be found along the Minuteman Bikeway in Boston. And, despite being painted bright yellow, they're often cited as culprits by cyclists visiting the ER.

The human brain is an economical instrument. It lets us see what it "thinks" we need to see, often discarding in the process the information it deems extraneous. Most of the time this type of economy is useful. But sometimes it proves erroneous, making us blind to what is literally right in front of us.

As cyclists we focus on making ourselves visible. But are there measures we can take, I wonder, to train ourselves to notice obstacles?


22 comments:

  1. Very useful pointer about reliability of our perceptions on the road. As you note, the brain is economical. It "fills in" the visual field but in especially tricky lighting/circumstances, appearances can be deceptive. Often in low light, the brain renders an object ahead as a person that upon drawing closer turns out to be a post or sign or whatever. Maybe we need collision avoidance systems for bikes:)! Does show that we need to do constant scanning of the road and not become complacent. Thanks. Jim Duncan

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  2. Apparently it is all to do with saccades and fixations!

    I came across this article by a pilot that explains why people sometimes "look but don't see".

    www.londoncyclist.co.uk/raf-pilot-teach-cyclists/

    Like a lot of things, training can improve this but of course road users aren't trained...

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    1. I immediately thought of that same article, Michael!
      The original source article is cited but can be found here:
      https://dl.dropboxusercontent.com/u/90471/1211%20Road%20Survival%20Guide%20Final.pdf

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    2. Thanks, this is very interesting. My husband is a glider pilot instructor and he talks about this as well.

      Visual illusions such as the "death farm," however, are a little different than target fixation: We look, and we do see, but we see something different from what is actually there.

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  3. Is it a perception test? My brain said there must be a missing picture, my gut said find a link...

    The local cycleway into the city has these death traps along with a random collection of stupid obstacles no cyclist would ever have allowed. Why do they only ever employ those who have no clue?

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    1. Ha. Do you mean the too-subtle colour of the links within the text?

      I found the previous colour distracting. But maybe I should make it a tiny bit more contrasty.

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  4. Michael, I believe these are different issues. The pilot's problem is that it is hard for converging aircraft to spot each other because converging paths define a constant relative bearing. Our peripheral vision is wired to detect relative movement, of which in collisions courses there is none except at the very end. Saccadic movement comes into the picture too but it is actually helpful - certainly better than attempting a 'fluid scan'. Optical illusions are a different matter, having to do with our pattern recognition hardware (that exists at several levels starting at the retina itself before going into the brain proper). Our gentle host provides a deadly example of a perspectival illusion, but optical illusions may be hazardous or benign depending on context. I am amused by the occasional bits of road (we have all encountered them) that seem to climb while descending or vice-versa. Architects and other artists have used perspectival illusions scientifically since the renaissance and empirically long before that. The Death Farm could cease to be with a more judicious choice of colour.

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  5. With all that talk I ended up not addressing the original question: how can we cyclists train ourselves to notice obstacles? Beyond the well know fact that our wheels follow our eyes, thus look ahead, not straight at the thing you want to avoid, I do not know if there are any useful general techniques. What we may call good 'ridership', a mix of attention, proficiency and preparedness, that's it.

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    1. Looking ahead works for me when I'm unsure of my maneuver or road position, both when cycling and when practicing driving.

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  6. All this about saccades and fovea is just fine. It is simpler than that.

    People see what they expect to see.

    People see what they want to see.

    Mere sensory input is far less potent than preconceived ideas.

    If you start to see your physical surroundings you will be a much safer cyclist. You will also be at constant loggerheads with your companions and with your culture. One reason why cycling is and will remain an outsider activity.

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    1. Than why don't I ever see Bigfoot? Huh? HUH?

      Maybe someday...

      Spindizzy

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  7. What you describe seems like the phenomenon "Target Fixation". Pilots are trained not to look directly at a an object.
    Look just to the side of the object otherwise they will be more likely to hit the object. I have read that that is why blinking bike lights are not allowed in Germany. I personally find them annoying and for a moment, stare at it.

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    1. Target fixation is a little different in that you notice the object, but are compelled toward it despite trying to avoid it. Happens to motorists too, especially at night. (And yes I believe that is the main reason blinkies are illegal in some countries.)

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  8. Have a listen to the podcast on fatcyclist with Megan Hottman, especially the last 5 or 10 mins about how she rides, very interesting

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  9. I would like to think anyhow I would take measures to avoid hitting a building or balustrade.

    There have been times I have definitely perceived a pot hole in my path yet failed to take evasive measures or slow the bike before riding into it.

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    1. Have you noticed this happening with specific bicycles?

      I have noticed that some bikes seem to be "psychic" in this regard, evading the pothole before my conscious reaction time catches up, whereas on other bikes I need to be more deliberate about it, and even then can end up riding straight into the thing despite knowing it's coming.

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    2. Forced to think about it, I would have to say I am less likely to do a duh! when riding the Kellogg road bike.

      Suppose one possible reason may be the Kellogg is the more adroit of my bikes. Path corrections can seem almost telepathic on that bike. Also, unlike my other bikes which I typically ride when I have to get somewhere, or do something other than riding, when I am on the Kellogg my sole purpose is riding a bike. Perhaps the riding senses are better attuned then.

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    3. For me, my DIY 650B bike is the most "auto-evasive," so I assumed it was the low trail. But of course it could be any number of things.

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  10. Thanks for the back story; I had been wondering about "the death farm"!

    My one close encounter with a stone wall was on a steep descent. My mates knew the road and I didn't, I had too much speed on and did not anticipate the hairpin bend. Lucky I got off with a broken arm!

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    1. Ouch, sorry to hear that. After a few situations that nearly resulted in same, if I don't know the route I always ride with a zoomed-in Garmin map in front of me, which allows me to anticipate bad bends.

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  11. Speaking of using the senses, sometimes one can be used in place of the other. Whilst I cannot see a car approaching over a crest on a narrow road I can usually hear it.

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