One reason that motorcycle accidents happen is drivers fail to look at their blind spots, or they simply fail to watch out for (and respect) motorcyclists on the road. Motorcyclists and driver of other vehicles may have a somewhat rocky relationship out on the road — but that shouldn’t prevent drivers in closed, protected cars from dismissing the presence of a motorcyclist. People on motorcycles are inherently more prone to injuries in an accident.

But why is it like this? Why do so many motorcycle accidents happen because the driver of a car “just didn’t see him coming?”

A professor at Texas Tech set out to discover the answer to this question, and her findings are quite interesting. The professor set up a computer simulation where participants would watch two objects — one a larger, farther away object, the other a smaller, closer object. The objects would come at them, and the participant had to judge which one would strike first. The program was designed so that the smaller, closer object would always strike first.

The professor found that participants repeatedly chose the larger, farther away object — and she wondered why.

It comes down to the way our brain perceives optical information. “Optical invariant” is the most accurate way our brain perceives this information. The object is projected onto the eye — and as we get closer, the object expands. The brain reads this and makes a determination. But the brain can also cheat, using shortcuts to generally determine how close an object is. When this happens, it is less accurate in regard to the proximity of smaller objects.

Source: Claims Journal, “Vehicle/Motorcycle Accident Link to Brain Miscalculation: Study,” Sept. 10, 2013