Reaction time test
How fast can you actually react to something you see? This is a simple visual reaction time test you run on yourself. Wait for the panel to turn green, react as fast as you can, and after five tries it shows your median time next to typical values.
Reaction time is one of the few things about your own nervous system you can measure in a few seconds without any equipment. The catch is that a browser can only measure it roughly, so treat your number as a way to race yourself and your friends rather than a lab result.
Ready when you are
You will do 5 trials. Wait for green, then click, tap, or press space. If you go before green it counts as a false start and you redo that trial.
The science
What this test measures is the whole loop from your eyes to your hand. Light hits your retina, the signal runs back to your visual cortex, your brain decides it is time to move, and a command travels down to the muscles in your finger. Studies of college-age adults put the accepted figure for simple visual reaction time at about 190 milliseconds for a flash of light. On an everyday laptop or phone it usually runs higher, somewhere around 200 to 270 milliseconds, so that is the range this test compares you against.
Here is the honest caveat. A browser test also folds in the time your screen takes to draw the color and the time your keyboard or touchscreen takes to register the press, and both of those vary from device to device. So read your number as a relative score against your own runs and against friends on the same setup, not as a clinical measurement of your nervous system.
Reference. Aditya Jain, Ramta Bansal, Avnish Kumar, and K. D. Singh. A comparative study of visual and auditory reaction times on the basis of gender and physical activity levels of medical first year students. International Journal of Applied and Basic Medical Research, 2015, volume 5, issue 2, pages 124 to 127. Read it here.
Built for The Neuroscience Review by Cameron Hunterton, who studies neuroscience at Columbia. Want more interactives like this one? Visit the full Lab or head back to the homepage.