Tap Space on every beat and click each target on its beat.
This task records timing error 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 metronome ticks. Press Space on every beat with your left hand. A target appears and its ring closes in on the next beat: click it exactly on that beat with your right hand.
Average timing error (both hands, on-beat). 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.
Doing two things at once costs something: the result shows how much each task slipped while the other was going on. This is practice on this task; it has not been shown to make you better at multitasking in general. 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.