Brain Games

Stroop test

A color word shows up in a different color of ink. Press the ink color as fast as you can. Your brain wants to read the word, and that's the whole test.

Press the button for the color of the ink. Ignore what the word says.

This game runs in your browser. Nothing you do here is sent to a server.

How to play

  1. Pick 20 words for a quick round or 40 for a steadier result.
  2. Press Start. A + appears, then a word like BLUE printed in some color.
  3. Press the button for the color of the ink. On a keyboard you can use keys 1 to 4.
  4. Go fast, but try not to make mistakes. Wrong answers don't count toward your times.
  5. At the end you see your average time on matching words, on mismatched words, and the gap between them.

What the Stroop test measures

Reading is automatic for most adults. When the word says RED but the ink is blue, your brain has to hold back the word to give the right answer. That holding back takes time.

The gap between your mismatched and matching times is called the Stroop effect. Psychologists use the task to study attention and self-control, which they call inhibition.

Where it comes from

John Ridley Stroop described the effect in 1935 in the Journal of Experimental Psychology. In his version people said the ink colors out loud from printed cards, and a timer measured the whole card.

This online version uses button presses and times every word on its own. The idea is the same, but the numbers aren't comparable with lab norms. Compare your results with your own earlier rounds.

Reading your result

Almost everyone is slower on mismatched words, so a positive number is normal. A smaller gap means the word got in your way less.

Your first round is usually the slowest because you're still learning the buttons. Play two or three rounds before you judge.

Tired, distracted or using a slow touchscreen? Your times go up. Try to test under the same conditions each time.

Color blindness

The four colors are red, blue, green and purple, and every button also has the color's name. If you have trouble telling some of them apart, the test will feel harder and your score won't mean much. That's a limit of the test, not of you.

FAQ

What is a normal Stroop effect?
There's no fixed number for online tests, because screens, devices and the way you answer all change the times. Nearly everyone is slower on mismatched words. Compare your result with your own earlier rounds.
Why does the test only count correct answers?
A wrong answer is often a fast guess. Leaving it out keeps your average times honest. Your accuracy is shown on its own line.
Can I use this as a medical or ADHD test?
No. It's a game version of a research task. It can't diagnose anything. If you're worried about attention or memory, talk to a doctor.
Does practice make the effect go away?
Practice usually makes you faster overall, and the gap can shrink a bit. It rarely disappears, because reading stays automatic.

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Last updated 2026-11-06