Neuro toolkit / 02
Reaction time game
When the panel turns green, tap as fast as you can. Five rounds, median score, bragging rights stored on this device only. It is a game: sleep, caffeine, age and your screen's own lag all move the number, which is half the fun.
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Last round
0 / 5
Rounds done
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Best median, this device
What actually moves the number
- In lab conditions, young adults average roughly a quarter of a second to react to a visual signal, and the latency lengthens gradually with age (Woods et al, 2015).
- Sleep debt, alcohol and sedating medicines slow reactions markedly; caffeine speeds them slightly.
- Your screen, browser and touch hardware add tens of milliseconds: scores travel between devices about as well as lap times travel between racetracks.
- Practice helps a little, warm hands help more than you would think, and anticipating the green (you tried it) is cheating.
Sources
- Factors influencing the latency of simple reaction time Frontiers in Human Neuroscience (Woods DL, Wyma JM, Yund EW, Herron TJ, Reed B), 2015Typical visual simple reaction times and what moves them.
Last reviewed: 2026-07-16
Slow today?
Reaction speed is exquisitely sensitive to short sleep and lingering caffeine. Our sister site sleep.mu can show you both: chart last night against your caffeine curve.