Choice reaction · Hick's law

Choice Reaction Time Test

A simple reaction test asks one question: did it change? This one asks a harder one: which one changed? Four pads, one lights up at random, and you have to hit the correct one. That extra decision costs you time. That’s Hick’s law, and you can feel it here.

Hit the pad that lights up

Four pads. One turns blue at random, so tap it fast. Ten rounds.

The cost of choosing

Here is the thing most reaction tests hide: in real life you almost never just react. You react and choose. A keeper guesses a corner. A driver picks the brake over the horn. A player picks which enemy to track. That choosing happens in the slowest, most flexible part of the reaction (the decision step in the middle), and it is exactly what this test measures.

Watch what happens to your number. A simple reaction might be 250 ms; with four pads to pick from, you will likely land north of 400. That gap is not you getting worse at reacting. It is the price of the decision, and Hick's law says it grows predictably: every time you double the number of options, you pay roughly the same extra slice of time. Two pads, four pads, eight pads: each step costs about the same, which is why a cluttered choice punishes you more than a simple one.

How to read your result

  • Median, not best. We take the median of your correct hits so one lucky pad does not flatter you.
  • Accuracy counts. Hitting the wrong pad fast is not skill. The test tracks your errors separately.
  • Compare it. Run the simple test and subtract: the difference is your decision time.

Frequently asked questions

What is choice reaction time?
It is how fast you react when you have to pick the right response from several options, instead of just reacting to a single signal. Adding choices adds processing time: simple reaction runs about 150–300 ms, while four-choice reaction often lands in the 300–500 ms range.
What is Hick's law?
Hick's law says reaction time rises with the logarithm of the number of choices: RT = a + b·log₂(N), with a around 200 ms and b around 150 ms per bit. In plain terms, each doubling of options adds roughly the same fixed amount of time. Read the full explainer in simple vs choice reaction time.
How do I compare this to my simple reaction time?
Take the standard reaction test first for your simple time, then this one. The gap between them is your decision cost: the time your brain spends choosing, not reacting.

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