Video: Using a High-Speed Camera and a Ruler to Test Reaction Times

There’s nothing like high-speed footage to put your reaction time in perspective. Knowing this, David Prager and Mauricio Balvanera of Distort put a high-speed camera to use capturing people doing the ‘ruler test,’ where a ruler suspended just above your fingers drops at a random moment, and you have to try and catch it as soon as possible.

In lighthearted fashion, they’ve dubbed the video Measuring Your Dumbness With A Ruler, and lest you start to think that you would do much better than the “slow” participants in the video, keep in mind that there’s some interesting science behind these tests.


It turns out that the average response time from seeing something happen, processing it, and acting on that information for us humans is about 190 milliseconds. If that seems like an eternity to a photographer who is constantly trying to capture the “perfect” moment, it’s worth noting what all has to happen during a ruler test.

MD PhD Neuroscientist Adam Gazzaley explains in the video:

If you laid out all the sequences it would be: anticipation, so they’re ready, maybe a motor sequence already ready to fire; then the sensation comes in, which is just the retina picking up the information that it started moving; then the perception, which is really an interpretation of what’s happening. And all that happens in the visual parts of the brain.


And that’s not all. Your pre-frontal cortex then has to decide to grab the ruler, the pre-motor cortex decides how to do it and “programs” an action, and then the motor part of your brain actually sends the signal that has you perform that action. Considering all that has to happen, 190 milliseconds average doesn’t sound too bad at all.

Of course, if the science doesn’t interest you, you can just watch the interesting 400fps footage of people going through all of these internal processes as the ruler makes its way towards the ground … sometimes much closer to the ground than the participants might like to admit.

(via Laughing Squid)