F1 reaction test

Nobody has published a study that timed people on a row of start lights in a browser. The nearest is a study of 1,469 adults who reacted to a single light on a screen: their average was 230.8 ms^[1]. That is a different task, because here you know when the lights can go out and you watch a row of them, so the first view of your result shows that average as a mark beside your time, never as a rank. How we measured this also draws your earlier results as short ticks on a ruler.

Your own numbers tell you plenty. If your middle time falls from one day to the next, you are getting sharper, or you are using a faster screen or mouse. If your fastest start is far ahead of your slowest, your attention comes and goes; that is normal, and it is the reason the middle time counts rather than the best one.

Each light is drawn at the start of a new picture on your screen, and the time of that picture is what the clock uses. The moment the lights go out is timed the same way: from the picture in which they disappear. Your press is timed from the browser's own record of your tap, click or key, not from the moment our code got round to reading it. On a 60 Hz screen each picture stays for a sixtieth of a second, so the moment the lights go out is known to within one picture.

A browser cannot see two small delays: the time your screen needs to show the picture, and the time your touch screen, mouse or keyboard needs to report the press. They are in every number you see, and they are the reason this page compares you with your own earlier results on the same device and never with other people. If you switch to another tab or app during a start, or the screen stalls while the lights are going out, that start does not count and you do it again.

Your result is saved in this browser and nowhere else: it never goes into a link, and it is never sent to us. You can read about us to see who makes the site.

If the lights always went out after the same wait, you would soon learn it and press before you could possibly have seen anything. A random wait takes that away: the lights stay on for between 0.2 sec and 3 sec after the last one comes on, and only the picture of the lights going out tells you when to press. The first lights are different. They come on at a steady beat of 1 sec, which gives you something to follow, but it says nothing about the last moment.

That is also why the jump start is a real rule here. Pressing early does not give you a quick time; it gives you no time at all, and the start is done again.

• Rest your finger on the button, the key or the screen before the first light, so that you only have to press and not to find it.
• Look at the middle of the row of lights, not at one light: you see all of them at once, and you see them go out at once.
• Do not try to guess. A guess is right only by luck, and a wrong one costs you the start.
• A wired mouse or a keyboard usually reports a press sooner than a touch screen does. Compare yourself only with results from the same device.
• Take a few starts to warm up. The first start of the day is often the slowest.

If you would rather have a plain signal, the reaction time test turns the whole screen green after a random wait. The sound reaction test asks you to react to a beep instead of to something you see, which is a different skill again, and your own results will show it.