Respond by the rule: same side, opposite side or by colour, with 2, 4 or 8 choices.
This task records choice 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 target appears in one of several places. Respond by the rule you picked: the same side, the opposite side, or by its colour. Use the arrow keys, or click or tap that side of the screen.
Efficiency score (median time ÷ accuracy). 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.
Choosing between more options costs more time: that pattern (Hick's law) is one of the most reliable findings in psychology. 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.
