What is the average human reaction time? And why your phone makes it worse
The average person clicks about 273 milliseconds after the screen changes color. Usain Bolt needed 146 at the start of his world record. Sounds like a huge gap, but it’s less than 130 milliseconds. I had to get these numbers right for the reaction duels in my game, so here’s what’s behind them.
Where 273 milliseconds comes from
The biggest pile of measurements is on Human Benchmark, where millions of people take a simple test: the screen turns green, you click. The median there is 273 ms. It’s a good number because it comes from ordinary people on ordinary computers, not students in a lab.
Median means half of people are faster and half are slower. If you get 250 ms, you’re above average. If you get 320, that’s not a disaster either, because part of it is your hardware.
What happens in that quarter of a second
Your eye catches the color change, the signal goes to your brain, your brain decides “now”, the signal travels to your hand, your finger presses. On top of that comes time that isn’t you at all, it’s the hardware:
- A 60 Hz screen shows a new frame every 16.7 ms, so the color change can appear a little late.
- A phone touchscreen usually adds more than a mouse. In my game I count about 30 ms for it.
- The browser and the operating system take a few milliseconds each.
That’s why on a phone the average human comes out at about 300 ms in my game, not 273. People aren’t slower on phones; the measurement is longer.
The sprinter and the 100-millisecond rule
In the 100 m final at the 2009 World Championships in Berlin, Usain Bolt reacted to the gun in 0.146 seconds and ran 9.58, still the world record. Sprinters react to a sound, not a picture, and they train this one movement for years.
The false-start rule is the interesting part. World Athletics counts any start faster than 0.100 seconds after the gun as a false start, even if the athlete moved after the signal. The idea is that no human can react that fast, so a start under 100 ms is a guess, not a reflex. If a reaction test gives you under 100 ms, you probably guessed too.
How to test your reflexes fairly
- Take several tries and look at the average or median, not your best result. One lucky try says nothing.
- Don’t guess. Clicking before the signal is a false start, and clicking “on a hunch” sometimes gives a great time that isn’t your reflex.
- Compare yourself on the same device. A phone result and a result on a computer with a fast monitor are two different things.
- Being tired or distracted slows you down. You’ll do worse in the evening after work than in the morning after coffee.
How it works in my game
In Smarter Than? there are reaction duels against opponents from a snail to a housefly. My average human is 273 ms with a mouse and 300 ms on a touchscreen, based on Human Benchmark data. The sprinter is 146 ms, from the Berlin final. The cat and the fly are estimates, since nobody has measured a cat tapping a screen. For every opponent I say whether the number comes from research, an estimate or a joke.
Sources
- Human Benchmark, reaction time test statistics (median 273 ms). humanbenchmark.com
- World Athletics, competition rules: a false start for any reaction faster than 0.100 s. worldathletics.org
- 2009 World Championships in Athletics, Berlin, men’s 100 m final: Usain Bolt’s reaction time 0.146 s, finishing time 9.58 s.