Duel, the reaction game
Wait for green, then tap as fast as you can. Five draws, and your median time in milliseconds is your score. It is the oldest measure in experimental psychology, and one of the steadiest (Donders, 1868, Woods et al., 2015b).
- Reaction speed
- Alertness
Play it live
Wait for green, then tap.
The screen turns green after a random delay, so tap at once, over five draws where the median counts.
Space bar works too
What it asks of you
Duel asks for simple reaction time, the delay between seeing a signal and moving your finger. Nothing to choose, nothing to remember, just the signal and you. That purity makes it a clean readout of how awake and ready you are.
The delay before green changes every time, so you cannot guess the rhythm. You have to stay ready and react, the exact state you need when something changes in front of you.
How to play
- Hold your finger above the screen, or above the space bar.
- Wait while the screen stays dark. The delay is random, between one and four seconds.
- The moment it turns green, tap.
- Five draws in a row. Your score is the median, so one slow draw does not spoil the round.
- Tap before green and that draw starts again. After more than three false starts the round does not count.
The research behind it
Franciscus Donders timed simple reactions in 1868 to measure the speed of mental processes (Donders, 1868). A century and a half later, it is still the reference measure of speed.
It is also one of the most reliable measures there is. Taken once a week for three weeks, a precise simple reaction time test reached a test retest reliability of 0.83 (Woods et al., 2015b). Your number is stable, so when it moves, it tells you something real about your day.
Many things shape it, age, the hand you use, the device, how alert you are (Woods et al., 2015a). That is why Duel compares you with yourself first, morning after morning.
On your weekly card
Duel feeds your Reflexes stat. It shares the reflexes slot of the morning routine with Grid, and the two take turns through the week.
On Sunday the reflex games of your week become one figure from 1 to 99 on your card, next to Memory and Focus.
Questions
What is a good reaction time?
The reaction time test places your median in a distribution of more than 70,000 public games (Human Benchmark, 2026). The average reaction time guide explains what moves it.
Does Duel get faster with practice?
Simple reaction time stays remarkably stable from one session to the next (Woods et al., 2015b). That is its strength. Duel works as a mirror of your form, sleep, focus, time of day, and the changes you see are real.
Phone or mouse?
Both work. Scores shift a little from one device to another (Passell et al., 2021), so keep the same device to compare your games.
Sources
- Donders F.C. (1868, translated 1969). On the speed of mental processes. Acta Psychologica 30, 412 to 431. doi.org/10.1016/0001-6918(69)90065-1
- Woods D.L., Wyma J.M., Yund E.W., Herron T.J. (2015). The effects of repeated testing, simulated malingering, and traumatic brain injury on high-precision measures of simple visual reaction time. Frontiers in Human Neuroscience 9, 540. PMC4637414. doi.org/10.3389/fnhum.2015.00540
- Woods D.L., Wyma J.M., Yund E.W., Herron T.J., Reed B. (2015). Factors influencing the latency of simple reaction time. Frontiers in Human Neuroscience 9, 131. doi.org/10.3389/fnhum.2015.00131
- Human Benchmark, score distributions embedded in humanbenchmark.com, read on 13 October 2026. Reaction time n 70 940, sequence memory n 35 868, chimp test n 27 233, number memory n 24 084. humanbenchmark.com
- Passell E., Strong R.W., Rutter L.A. et al. (2021). Cognitive test scores vary with choice of personal digital device. Behavior Research Methods 53(6), 2544 to 2557. PMC8568735. doi.org/10.3758/s13428-021-01597-3
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Your full card, every Sunday.
Three 20 second games each morning, phone down sessions, and a card with six stats revealed every Sunday. Coming soon to the App Store, Google Play next.
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