January 30, 2014
I found out about this visual effect called optic flow and how it helps a Honey bee (aka honeybee) determine it’s speed and relative position to objects. This all makes sense….the faster you are going, the faster objects near you move by. That sensation is called optic flow and there are all kinds of mathematical formulas developed to measure that. But researchers wanted to see how a Honey bee figures out it’s place in space (there’s an interesting place called the All Weather Bee Flight Facility at the Australian National University). You know, you can fool these insects if you mess with their surroundings. If you put a Honey bee in a solidly painted room, it can’t figure out if it’s really near anything when it flies. Nothing is moving by it so it will fly into the wall thinking it’s just in open space. What a dirty trick! Apparently Honey bees don’t have sonar.
In this book I’m reading called, The Eye – A Natural History by Simon Ings, this Honey bee researcher wanted to know how a pilot knows how to land a plane as the plane is aiming down at the runway. The pilot said he looks at a point and then when the ground “explodes” you flatten out. I remember that effect. My CFI (certified flight instructor) demonstrated the landing technique to me and I thought we were going to explode in a metal carnage on the runway but right before that he leveled the plane for a smooth landing. I bet a Honey bee never worries about a crash landing. They’re pretty light weight anyway so bumping into a wall might not be carnage for them….just a slight brain bruise. We humans sure do need a lot of nurturing and mind control before attempting strange things like flying a small plane.
When you’re driving down a highway with stripes on the road or if you’re a passenger, those white lines move by at a certain rate which I’ll figure out for you. We’re not landing on the road with a plane but as you’re driving down the road those stripes are flowing by at a certain pace like….optic flow. I found out that the distance between them is supposed to be 30 feet and the length of the stripe is 10 feet. I used a chart from an Indiana state drivers manual (in case you want to see what Indiana says about driving) to calculate how fast your car would have to go to make each stripe go by once per second. That would be about 24 mph. That’s pretty slow. If you were going 72 mph (3 times as fast) then 3 stripes would go by each second. Since those stripes would go by that fast it’s easy to see how one might think the stripes were closer together than they really are. But who uses stripes to estimate speed when we’ve got it easy by looking at a speedometer? Maybe I’ll try it and see how close I can guess how fast I’m going by timing the stripes next time I’m flying down the freeway (in a car).
Going back to the exploding view that a pilot has when headed towards the runway I wonder how else we use optic flow or if we’re even aware of it. I think it’s more of a subconscious calculation like our little Honey bee friends use when they’re flying around….subconscious except only when you’re in the front seat of a small plane headed towards concrete for the first time!
This picture was taken out of the book I mentioned in this article.