What is choice reaction time?
Choice reaction time is how long it takes to give the right response when there are several possible signals, each with its own response: here, four squares and four keys. Simple reaction time, by contrast, has one signal and one response. Choosing takes extra time, so choice reactions are slower. A goalkeeper deciding which way to dive and a driver choosing between braking and swerving are everyday examples.
How this test works
Four squares sit side by side. After a short random gap, one of them lights up, and you respond to that one: tap or click it, or press its key. The keys are D, F, J, K, left to right, so two fingers of each hand rest over the four squares.
As soon as you answer, a tick or a cross shows on the square you chose and the next round starts on its own, after a gap of between 0.8 and 2 seconds. The same square never lights twice in a row, so you can't win a round by pressing the same key again before you have looked. There are 20 rounds.
If you press during a gap, before anything is lit, you see Too soon. That press isn't scored and the gap starts again.
How we calculate your result
The timing works exactly like our Reaction Time Test: the clock starts in the animation frame in which the square is drawn lit, and stops at the timestamp your browser gives your press the moment it arrives, using the browser's high-resolution timer.
Your result is the average time of your correct answers. Wrong answers are left out of the average, because a fast press on the wrong square isn't a reaction to what you saw. They still show in your score, as the number correct out of 20, so a fast average with many mistakes can't pass for a good run.
Why this is slower than the simple test
In the simple test there is one signal and one response, so you can be ready to press before anything happens. Here you first have to see which square lit up and then pick the matching response. That decision takes time, and adding possible choices generally makes reactions slower, a pattern psychologists call Hick's law.
Try both tests on the same device in the same session. The gap between your two averages is roughly what the choice costs you, and because both tests share the same timing method, most of the device's own delay is the same in both.
Simple vs choice reaction time
| Simple reaction time | Choice reaction time | |
|---|---|---|
| Signals | One | Several |
| Responses | One | One for each signal |
| Decision | None: just go | Pick the response that matches the signal |
| Can you get ready? | Fully: your finger can be on its way | Only partly: you don't know which key yet |
| On this site | Reaction Time Test | This test |
Speed against accuracy
You can nearly always go faster by being less careful, and you'll see it in your score: the average drops while the number correct drops too. Neither number is the "real" result on its own. For runs you want to compare, aim for few mistakes first and speed second, and keep that approach the same every time.
What can change your result
- Keyboard or touch. Keys under resting fingers need no aiming. On a touchscreen your thumb has to travel to the right square, which adds time that has nothing to do with deciding.
- The display and input device. Refresh rate, touch processing and keyboard polling all add a little to every round, as they do in any browser reaction test.
- Hand position. Starting each round with your fingers already on D, F, J, K matters more here than in the one-key test.
What this test does not measure
It measures how quickly and accurately you pick one of four responses to a visual signal on your device. It isn't a medical or psychological assessment, and the result says nothing about intelligence or about how you would do in any other task. Results from different devices aren't directly comparable.
Prefer a single signal? The Reaction Time Test has one. For something that tests seeing rather than reacting, try Mental Rotation.