Follow a drifting ring with your cursor and react fast to dots in your side vision.
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.
The centre ring drifts slowly around the screen: keep your eyes and your cursor inside it. A dot appears out in your side vision: press Space, click or tap as fast as you can. Unlike Peripheral Detection (which asks whether you saw a brief flash), this one is about reaction speed while your hand is busy following.
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.
A screen covers only part of your field of view; sit at the same distance each time. 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.
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.
