Reaction Time Game
Wait for green. Tap. Do not fall for the traps.
About Reaction
Reaction is the classic reflex test, with a twist for higher levels. A grey box says 'Wait…'. After a random delay it turns green and shows TAP!, and you tap as fast as you can. Your reaction time is shown in milliseconds, and the score depends on how close you get to the fastest times people can reach.
A run has eight rounds, more than most games, because reaction times vary a lot from one attempt to the next. On the first levels the signal simply comes after one to three seconds. From level 4 an orange decoy flashes up, and from level 7 twice, saying 'Not yet!', and tapping on it ends the round with 0 points, so patience matters as much as speed.
How to play
- Wait with your finger ready. The box shows 'Wait…'. Do not tap yet.
- From level 4 on, an orange decoy can flash up. It means 'not yet': ignore it.
- When the box turns green and says TAP!, tap anywhere on it, or press the space bar.
- Your time in milliseconds appears, together with the score.
Wait until the box turns green and says TAP, then tap as fast as you can. Tapping too early scores zero. On harder levels red decoys appear: do not tap on those.
How scoring works
The score is 100 for 150 ms or faster and falls in a straight line to 0 at 600 ms. For example, 250 ms earns about 78 points, 300 ms about 67 and 400 ms about 44 points. A tap before the green signal, or on a decoy, earns 0. If you do not react within two and a half seconds the round ends with 0.
The time is taken from the moment the green colour is painted on the screen to your touch or key press event. Your device adds its own delay of tens of milliseconds, mainly through touch screens and display refresh, so results on a phone are somewhat slower than with a fast keyboard or mouse.
What it trains
The game trains simple visual reaction time and also response inhibition, the ability to hold back a response, which is a key part of executive control. The decoys test whether you can hold your finger still until the real signal comes, as drivers do at a traffic light.
It is not a measure of intelligence or health. Reaction time varies with sleep, caffeine, age, device and mood, so treat your result as a snapshot of today.
Tips for a higher score
- Rest your finger just above the box, not on it. A very light touch is faster than a push.
- Look at the whole box instead of staring at the centre, and stay relaxed. Tension slows the response.
- Do not try to anticipate. Guessing the timing leads to false starts, which score 0, while a slight delay costs only a few points.
- Play with a keyboard or a mouse on a computer to avoid the extra touch latency of a phone screen.
- Take short breaks. Reaction time gets worse when you are tired, and a rested run of eight rounds is the best way to test yourself.
The idea behind it
Simple reaction times to a visual signal have been measured since Hermann von Helmholtz in the 1850s and Franciscus Donders in the 1860s. Modern studies find averages of roughly 200 to 250 milliseconds in young adults, with auditory signals about 30 to 50 ms faster than visual ones, since sound is processed more quickly by the brain.
Reaction times increase slowly with age and are influenced by alertness. The addition of a decoy brings in a different effect, the speed-accuracy trade-off, where responding faster costs more false starts. Data from large online samples show that values below 150 ms are usually anticipations, not true reactions.
Frequently asked questions
Why is my result slower on a phone?
Touch screens, display refresh and the browser add a delay of several tens of milliseconds, so your device matters. Compare results only on the same device.
Is the delay random?
Yes, it is drawn at random for every round, so you cannot learn the timing.
What other skills are similar?
Go / No-Go in the Focus category also tests holding back a response, and Rhythm tests timing.
Related games
Free, no account. Your best scores are saved on your device.