Stroop Test

By the Reaction Benchmark team · Published

Color words appear on the screen in the wrong color, like BLUE written in red ink. Pick the color of the ink, not what the word says. There are 24 words, your score is the time it takes, and every wrong pick adds one second.

It is the classic Stroop task from 1935, the best-known test of how well you can hold back an automatic habit. One round takes about half a minute.

Press Start to begin

24 words. Pick the color of the ink, not what the word says. A wrong pick adds 1 second, and the word stays until you get it.

How to play

Color words appear in a different ink, and each time the ink color is picked rather than the word, then the time shows. Tap to pause.
  1. Press StartThe clock starts the moment the first word appears.
  2. Look at the inkIf BLUE is written in red, the answer is red. Ignore what the word says.
  3. Pick the colorTap one of the four color buttons, or press 1 to 4 on a keyboard. A right pick brings the next word at once.
  4. Finish all 24Half the words match their ink and half do not. Each wrong pick adds a second, and the same word stays until you pick its color.

What the Stroop effect is

In 1935 the American psychologist John Ridley Stroop asked people to name the ink color of printed words. When the word itself was a different color name, such as GREEN printed in red, people were clearly slower than when they named plain patches of color. That slowdown is the Stroop effect, and it has been repeated in a great many studies since. By 1991, a review by Colin MacLeod was already summing up half a century of research on it.

The reason is that reading is automatic for a skilled reader. You cannot look at a familiar word and not read it. When the word and the ink disagree, your brain has to stop the answer that reading hands you and give the one the color asks for. The test measures how quickly and cleanly you can do that.

That is why the words are shown in the language of the page. The effect is strongest in a language you read without thinking. This is a game and a classic psychology demonstration, not a medical test for ADHD, dementia or anything else.

What counts as a good time

The badge on your result follows this table. Times are stored in milliseconds, so both units are shown. Published Stroop studies report time per word rather than per round, so the lines below are per-word times multiplied by 24. Two studies set the range. In a lab study by Zurrón and colleagues (2009), people answered with two buttons in about 563 ms for matching words and 623 ms for mismatched ones. In an online study by Crump and colleagues (2013), people typed out the color name, which is slower: 859 ms and 1,152 ms. Four buttons sit between those two setups.

TimeBadgeWhere the line comes from
under 13.2 s (13200 ms)Superhuman550 ms a word, faster than the lab average for matching words even with twice as many buttons.
13.2-15.6 s (to 15600 ms)Pro tier650 ms a word, about the lab average for mismatched words.
15.6-18 s (to 18000 ms)Skilled750 ms a word, the faster end of the gap between the two studies.
18-24 s (to 24000 ms)StandardUp to 1,000 ms a word, close to the online study's average across both kinds of word.
24-30 s (to 30000 ms)Warming upUp to 1,250 ms a word, slower than the online study's mismatched words.
30 s or moreNeeds practicePast that. Tiredness and second-guessing show up here first.

These lines are a first estimate. No published norms use exactly this four-button setup, so the table will be checked against real results from this site once enough rounds come in, the same way the other new tests were.

What it measures

The main skill is holding back an automatic response. Psychologists call it inhibition. Reading the word is the fast, easy answer, and every mismatched word asks you to block it and give the slower one.

Your result also shows your own Stroop effect: how much slower you were on mismatched words than on matching ones, in milliseconds. The smaller the number, the less the words got in your way. In the online study above, the average gap was about 290 ms.

The total time adds plain processing speed on top. Seeing a color and moving your finger to the right button takes time even when the word agrees with the ink, which is why matching words count as well.

Getting faster

Look at one letter

Some people find it helps to rest their eyes on a single letter instead of taking in the whole word. The color is the same on every letter, and the meaning is easier to tune out.

Learn the button spots

Once your thumb knows where red and yellow sit without looking, the only work left is the color itself. On a keyboard, keep your fingers resting on 1 to 4.

Do not hurry the first word

The first few words set your rhythm. A calm, steady pace beats a fast start followed by a string of second-guesses.

Accuracy before speed

A wrong pick costs a full second, which is longer than most answers take. If you catch yourself reading, let the color decide anyway.

The effect never fully goes away with practice, because you cannot stop being a reader. What practice changes is how quickly you recover after the word pulls at you. Your first few rounds usually improve the most.

If you have color blindness, some of these colors may be hard to tell apart, and the test may not work for you. The four colors were picked so they stay as far apart as possible for the most common red-green types, but full color blindness makes the task impossible by design.

Frequently asked questions

Why does my time jump during a round?

You picked a wrong color. Each wrong pick adds one second at once, and a red "+1 s" appears on that button. The result shows your accuracy and how many seconds were added.

Can I use the keyboard?

Yes. Keys 1 to 4 match the four buttons from left to right and top to bottom. The numbers are shown on the buttons when you use a mouse.

Why did the round stop when I switched tabs?

Browsers slow timers down in hidden tabs, so the time would no longer be accurate. The round is cancelled and you can press Start to play a fresh one.

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