Guest post: Inattentional Blindness & Conspicuity

Originally, I had expected to be laid up today following carpal tunnel surgery. 

So when Phillip Young sent me the following piece, I thought it would make a perfect guest post for today when I wouldn’t be able to write. 

But now that my surgery has been cancelled due to the surge in Covid-19 cases, I want to share it with you anyway. 

Because it could help you be seen. And that could make all the difference on your next ride.

………

Good info that may save your life about what car drivers actually see especially inconsequential bicyclists and motorcyclists.

Before I read it I too couldn’t understand how drivers don’t see cyclists, often cyclists in bright clothing during daylight.  After all, I know I saw them. Our brethren Down Under have a term…SMIDSY (Sorry Mate, I Didn’t See Ya). Or you hear about drivers who say “the cyclist came out of nowhere.”  I remember thinking drivers say this stuff as an excuse because they were texting or something.

But this article by Marc Greek Ph.D. explains the difference between sensory conspicuity and cognitive conspicuity, and how they’re both important for us to notice something. It talks about looking at something and not seeing it, and why.  And most important to cycling safety, or the thing that made the biggest revelation for me, is the importance of the role that relevance plays in cognitive conspicuity. In short, the more relevant something is to us for some reason, the more likely we are to notice it, and vice-versa.

First of all, this explains why we cyclists are better at noticing cyclists when we are driving than are drivers who are not cyclists. Cyclists are inherently interesting to us.  Do we know them? What are they riding? What are they wearing? What are they doing? Would we do that? These are all questions we cyclists are likely to ask ourselves about any randomly-encountered cyclist that non-cyclist drivers would never ask and couldn’t care less about. This makes any cyclists in our visual space relevant to us and therefore likely for us to notice. For non-cyclist drivers there has to be more for the cyclist to be relevant to them and therefore for them to be likely to take notice.

Secondly, I think it explains why cyclists are generally noticed and treated better in places where 80% of drivers also regularly ride bikes than here where it’s like 2%.

Most importantly it explains why drivers often don’t notice cyclists as they pass them.  Consider:

  • The less relevant the cyclist is to the overtaking motorist the more likely the motorist is to not notice the cyclist.
  • Compared to a cyclist using the full lane and “in their way,” edge riding in a travel lane makes a cyclist easier to pass and, so, less relevant and more likely to be overlooked to approaching motorists
  • Riding in a traditional striped class 2 bike lane makes a cyclist even easier to pass and less relevant and therefore even more likely to be overlooked than a cyclist edge riding in a travel lane.
  • Riding in a class 2 bikeway separated from the travel lane by physical barriers makes a cyclist even easier to pass and less relevant and therefore even more likely to be overlooked than a cyclist riding in a striped bike lane.
That is, a driver’s primary focus area (see graphic below) — naturally concentrated on the course ahead — is likely to stop at the right edge of their  lane. And that edge is probably sharper when it has barriers than when it’s just paint. And it only makes sense that the further a cyclist is from a driver’s primary focus area — “further” by relevance not just pure physical distance — the more likely they are to be unnoticed by the driver.
CBEB124C-951F-4A47-B2DC-343366B3D19B.png

Attention test: https://www.youtube.com/watch?v=vJG698U2Mvo

Some excellent bicycling safety links at the bottom of the article.

Wear brightly colored [Yellow (best), White (2nd Best) or Orange (3rd Best)]:

  1. Jersey
  2. Helmet
  3. Reflective vest
  4. Shoes, shoe covers, or socks and pants (bio movement)
  5. Front and back blinky lights. Lights with bio movement are the best on arms and legs.
  6. Spoke reflectors and other rotating reflectors (pedals and cranks)

One comment

  1. Harv Woien says:

    The above mention of riding with blinky lights is, to me, of paramount importance. After starting to use daytime running lights (DTR) on my bike, I noticed that passing car traffic would give me more clearance. The brighter the tail light, the more clearance distance I get. I don’t use the (relatively) feeble bicycle lights, I use red LED flashlights with several hundred lumens output. Random pattern blinking is best, so set light to “SOS” if possible.
    .
    For the front DTR, I use a high output green or amber LED flashlight set to blink and aimed high. White lights will blend into the various bright daylight reflections in the background. I have experienced car drivers slow down and ask me about my green headlight. It is that conspicuous. For night riding, I switch to a steady white headlight of 500 to 1000 lumens, which is brighter than a typical car headlight, taking care to aim it low enough to avoid blinding oncoming car drivers.

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