What is a Stroop test?

A color-word game. You see a color word, such as RED, printed in blue or in red letters, and you choose the color of the letters. It is named after J. Ridley Stroop, who described the effect in 1935.

What is a good score?

We do not say, because we do not compare your result with other players. You compare with yourself: same device, about the same time of day, then see whether your mistakes and your difference in milliseconds change.

Can the difference be negative?

Yes. It means you were faster on the mismatched turns than on the matching ones. In a round of 40 turns that can happen, for example if you only get into your stride halfway through.

Do mistakes count toward my time?

No. Only correct answers go into the averages. Mistakes are listed separately, along with any turn where you had not chosen after 4 seconds.

What if I find red and green hard to tell apart?

Then the difference is harder to read in this game, because the colors are fixed. In the attention test, color plays no part.

Stroop test

Tap the color of the letters and ignore what the word says. 40 turns, about a minute.

Take the full Brain Check

A Stroop test is a color-word game: you see a color word and choose the color of its letters, even when the word says something else. After 40 turns you see your average reaction time on matching and mismatched words, the difference in milliseconds and your mistakes.

How the game works

One word at a time appears on the dark panel: red, blue, green or yellow. Under the panel are four buttons with those same colors, always in the same place. Pick the color the letters are printed in and leave the word alone. If it says GREEN in yellow letters, yellow is right. On a keyboard you can also press 1, 2, 3 and 4.

A round has 40 turns. In 20 of them the word matches its color, and in the other 20 it does not. Every word and every color comes up 10 times, so guessing one color gets you nowhere. There is a short pause between turns. If you have not chosen after 4 seconds, the turn counts as a mistake and the game moves on, so one glance away from your phone does not end up in your average.

Why mismatched words usually take longer

A fluent reader reads a word without deciding to. With GREEN in yellow letters, the word and the color point at two different buttons, and sorting that out takes a moment. With RED in red letters, both point the same way. John Ridley Stroop described this difference in 1935, which is why the game carries his name. This game measures it in milliseconds, and after each round you see how large it was for you.

What your result shows

Three times and a count: your average on the matching turns, your average on the mismatched turns, the difference between them and the number of mistakes. Only correct answers go into the times. A mistake is often a reaction to the word that came too fast, and counting it would make your average look better than it was.

The result describes how this round went, today, on this device. It is not a medical test, and you do not get a comparison with other players.

Comparing your score with yourself

Your best round stays on your own device. We pick it on the number of mistakes first and the smallest difference second, because otherwise you could set a record by tapping at random on the hard words. To put two rounds side by side, play them on the same device: a touchscreen and a keyboard give different times, and that comes from the screen. Two rounds in a row can also differ by tens of milliseconds for no particular reason.

More games

For plain speed, try the reaction time test. In the attention test you look for the difference between shapes. All the games with a score are on the brain games page.

Frequently asked questions

What is a Stroop test?: A color-word game. You see a color word, such as RED, printed in blue or in red letters, and you choose the color of the letters. It is named after J. Ridley Stroop, who described the effect in 1935.
What is a good score?: We do not say, because we do not compare your result with other players. You compare with yourself: same device, about the same time of day, then see whether your mistakes and your difference in milliseconds change.
Can the difference be negative?: Yes. It means you were faster on the mismatched turns than on the matching ones. In a round of 40 turns that can happen, for example if you only get into your stride halfway through.
Do mistakes count toward my time?: No. Only correct answers go into the averages. Mistakes are listed separately, along with any turn where you had not chosen after 4 seconds.
What if I find red and green hard to tell apart?: Then the difference is harder to read in this game, because the colors are fixed. In the attention test, color plays no part.