Attention and Control
The Stroop test shows how hard your brain works to ignore a word it reads automatically. Name the ink color as fast as you can and see how much the written word slows you down.
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This task depends on color vision. If you have a color vision difference, the Flanker Test or the Go/No-Go Test measure similar control processes without relying on color.
Example
The second card is harder. Your brain reads "blue" before it can stop itself, and that tiny conflict is exactly what the test measures.
Reaction times are measured from the frame the word is painted on screen, using the browser high resolution clock.
The same color-word conflict that John Ridley Stroop described in 1935, adapted for a modern screen.
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See the interference effect, congruent and incongruent times, accuracy, speed per minute and a trial-by-trial chart.
Practice mode tells you after every answer whether you were right, so you learn the task before it counts.
Ten more classic tasks for attention, speed and memory. Each one runs in your browser and keeps its own history.
How much slower you are when the word and the ink disagree. This is the classic Stroop score.
How it is calculatedIncongruent mean RT minus congruent mean RT, correct trials only
The share of trials where you picked the ink color correctly.
How it is calculatedCorrect answers divided by all answers, as a percent
Your typical response speed on correct answers. The median ignores a few unusually slow trials.
How it is calculatedAverage and middle value of correct reaction times
A single number that combines speed and accuracy, useful for comparing sessions of different lengths.
How it is calculatedCorrect answers divided by active minutes
These bands are site-defined guidance for adults on a desktop computer or a recent phone. They are not population norms and not a diagnosis.
| Band | Range | What it means |
|---|---|---|
| Excellent | below 60 ms | The word barely slowed you down. |
| Good | 60-119 ms | A small, healthy amount of conflict. |
| Average | 120-199 ms | Where many sessions land. |
| Needs practice | 200 ms or more | The word pulled strongly on your attention. |
| Band | Range | What it means |
|---|---|---|
| Excellent | 95% or more | Almost every answer was right. |
| Good | 85-94% | A few slips, mostly on mismatched words. |
| Average | 70-84% | Speed may be costing you accuracy. |
| Needs practice | below 70% | Slow down and focus on the ink. |
In 1935 the American psychologist John Ridley Stroop published a study in which people read color words and named ink colors. Naming the ink took much longer when the word named a different color.
The finding was so reliable that it became one of the most repeated experiments in psychology. Today the task appears in thousands of studies on attention and self-control.
The Stroop test measures selective attention and cognitive control: your ability to focus on one feature, the ink, while suppressing another, the word.
Researchers often describe this as a test of inhibition. You have to hold back a fast, automatic response and give a slower, deliberate one instead.
For a practiced adult, reading is automatic. You cannot look at a familiar word without understanding it, even when you try not to.
Naming a color is a less practiced skill. When the two compete, the brain has to resolve the conflict before answering, and that extra step costs time. Brain imaging studies link this conflict monitoring to the anterior cingulate cortex and the prefrontal cortex.
Sleep, stress, caffeine, age and reading fluency all affect Stroop performance. Testing in a language you read less fluently usually shrinks the effect, because the word is less automatic.
Practice also matters. Most people improve over the first few sessions as they learn to focus on the ink. That is why we suggest averaging several Standard sessions before drawing conclusions.
Say the ink color of each word out loud. The left card is congruent, the right card is not. Notice how the right one makes you hesitate.
Signs work best when color and meaning agree. A green STOP sign would slow drivers down.
Fluent readers cannot switch reading off, which is exactly why the Stroop effect exists.
A red button labeled Continue confuses people. Good apps keep color and label in agreement.
Brands rely on color associations. Mismatched colors make messages harder to process.
The effect is a vivid way to show students how practice turns skills into automatic habits.
Shoppers expect certain colors for certain flavors. Breaking the pattern slows recognition on the shelf.
Psychologists use Stroop tasks to study attention, aging, bilingualism, stress and the effects of sleep loss.
Teachers use the effect as a memorable classroom demonstration of automatic processing and how habits shape perception.
Some people use short daily sessions to notice how sleep, focus and routines change their performance over time.
Clinicians use standardized Stroop versions as one part of larger assessments. An online test like this one cannot diagnose anything.
Compare sessions on the same device and input method. A phone and a laptop give different times.
Some people find it helps to soften their focus and look at the color of the letters rather than their shape.
A fast wrong answer helps nobody. Aim for accuracy above 90 percent, then let speed come naturally.
Fatigue and stress raise the interference effect. Pick a quiet moment and close other tabs.
It is a classic attention task where color words appear in colored ink. You name the ink color and ignore the word. The slowdown on mismatched words is called the Stroop effect.
After a short countdown, a fixation cross appears for a quarter of a second, then a color word. You choose the ink color with a button or a key. A new word appears right after each answer until the timer runs out.
Practice takes 30 seconds, Standard takes 60 seconds and Challenge takes 3 minutes. Most people use Standard for tracking progress.
Yes. Use the pause button, or switch tabs and the test pauses automatically. The interrupted word is replaced with a new one. The Stop button ends the session and shows your result if you answered at least 10 words.
Any modern browser on a computer, tablet or phone. A keyboard gives the most precise timing, but touch works well too.
The interference effect shows how much the written word slowed you down. Accuracy shows how often you chose correctly. Lower interference with high accuracy means stronger control.
On this site, an interference effect below 60 ms with accuracy of 95 percent or more falls in the Excellent band. These bands are site guidance, not clinical norms.
Open the History page from the menu or use the View history button on the result screen. You can filter, sort, export and import your results there.
Results are saved only in your own browser storage. Nothing is sent to our server, and clearing your browser data removes them.
Reload the page and try again. If the test does not start, check that JavaScript is enabled and that you are using an up-to-date browser. Private browsing can block saving results.
The Stroop task depends on telling colors apart, so some color vision differences make it unreliable. The Flanker Test and the Go/No-Go Test measure similar control skills without relying on color.
Results depend on age, device, sleep, language, mood and practice. Average several sessions before drawing conclusions. This is not a medical or psychological diagnostic tool.
It takes about a minute. Your results stay private in this browser.