Respond the moment the stimulus changes.
This task records reaction latency on a fixed, repeatable version of the task. Your result is comparable to your own previous attempts on the same device.
It does not diagnose anything, and it does not claim to improve anything beyond performance on this task. Reported times include display and input latency from your own hardware.
Stop if you feel dizzy, nauseous or strained.
A ring shows "Wait…". When it turns into a gold ball (or the shape or sound you chose appears), click, tap or press Space as fast as you can. Pressing before that counts as too soon.
Median reaction time. Lower is better. Each difficulty (Easy, Normal, Hard) keeps its own personal best, and custom settings are saved but not ranked, so your bests stay comparable.
Reaction times include roughly 10–50 ms of screen and input delay from your own device. Compare against your own earlier results on the same device and input, not against other people's. Anything faster than 100 ms is treated as a guess and repeated. Getting faster on this test is practice on this test; it has not been shown to make you faster in games or daily life. Not medical advice.
A reaction time is several things added together: seeing the change, deciding what to do, and moving. On a computer it also includes your screen and mouse or touchscreen, which add roughly 10 to 50 milliseconds depending on the device.
More choices take longer (Hick's law), and holding back a response has its own timing. We use the median of several trials and ignore anticipations under 100 ms, because those are guesses.
Respond by the rule: same side, opposite side or by colour, with 2, 4 or 8 choices.
Follow a drifting ring with your cursor and react fast to dots in your side vision.
Respond to the arrow fast. Hold back when the stop signal comes.
