Stroop Test
A color word appears in colored ink. Your job: click the color of the ink, not the word you read. It sounds easy until the word and the color disagree.
A color word appears in colored ink. Click the ink color, not the word. 24 words, as fast and accurately as you can. Keyboard: R, G, B, Y.
How this Stroop test works
24
words, one at a time
4
colors: red, green, blue, yellow
½
of the words match their ink
In half of the words the word and the ink match (congruent); in the other half they don't (incongruent). Click the button for the ink color, or press R, G, B or Y on a keyboard.
| Number | What it is |
|---|---|
| Matching | Average time on congruent words |
| Mismatched | Average time on incongruent words |
| Stroop effect | Mismatched minus matching: the cost of interference |
| Accuracy | Share of correct answers; only correct answers count for the times |
Why is it so hard? The Stroop effect explained
For a fluent reader, reading is automatic: you cannot look at a familiar word and not read it. Naming a color takes a deliberate step. When the two point to different answers, the word you've already read competes with the color you're supposed to say, and resolving that conflict costs time.
| Explanation | The idea |
|---|---|
| Speed of processing | Words are processed faster than colors, so they arrive first |
| Automaticity | Reading needs less attention than color naming, so it happens whether you want it or not |
| Modern models | Combine the two: the stronger, more practised pathway interferes unless attention holds it back |
The original 1935 experiment
100
items per card in Stroop's experiment
≈ 74%
longer to name the ink of conflicting words than plain color patches
≈ 400
studies of the effect reviewed by 1991
John Ridley Stroop compared naming the ink colors of conflicting color words with naming the colors of plain colored squares. Reading the words aloud, by contrast, was barely affected by the ink color. That asymmetry is the heart of the effect: the automatic process disrupts the controlled one, not the other way around.
What the Stroop test is used for
Because it isolates the ability to suppress a strong habit, the Stroop task became a standard measure of inhibitory control, one of the core executive functions alongside working memory and mental flexibility. Researchers use versions of it to study:
- attention
- aging
- fatigue
- bilingualism
Variations on the Stroop task
| Variant | The task |
|---|---|
| Emotional Stroop | Name the ink color of emotionally loaded words; delays can reveal what grabs attention |
| Numerical Stroop | Judge which of two digits is physically larger when the larger number is printed smaller |
| Spatial Stroop | Respond to an arrow's direction, or a word like LEFT shown on the wrong side of the screen |
| Reverse Stroop | Read the word and ignore the color: much easier, which is exactly the original asymmetry |
How to improve your score
With practice, the gap between matching and mismatched words usually shrinks. Two approaches people find useful:
- Soften your focus so you see a patch of color rather than a word.
- Name the color first, in your head, before the word “lands”.
Try the Schulte table for visual search or the reaction time test for pure speed. In the Brainura app the Stroop Test is one of 26 short games, with levels that adapt as you improve.
Frequently asked questions
What is the Stroop effect?
The delay you experience when the meaning of a word conflicts with the color it is printed in. Naming the ink of the word RED printed in blue takes longer, and causes more mistakes, than naming the ink of a word that matches its color.
What does the Stroop test measure?
Mainly the ability to hold back an automatic response (reading) in favor of the one the task asks for (naming the color). Psychologists call this inhibitory control or interference control, one of the executive functions.
What is a good Stroop test score?
Almost everyone is slower on mismatched words, so a positive difference is normal. A smaller difference with high accuracy means you are handling the interference well. Scores vary a lot between attempts, so compare a few runs on the same device.
Who discovered the Stroop effect?
The American psychologist John Ridley Stroop published the classic experiments in 1935, in his doctoral work. Earlier researchers had noticed that naming colors is slower than reading words, but Stroop showed how much conflicting words slow color naming down.
Can I take the Stroop test if I am color-blind?
You can try, but if some of the four colors are hard to tell apart for you, your result will reflect color discrimination rather than the Stroop effect. The buttons show the color names to help.
Is this a medical or diagnostic test?
No. Clinicians use standardized versions of the Stroop task as one part of a wider assessment. This online version is for curiosity and practice, and its score says nothing about any condition.
Try next
Repeat digits forwards, backwards or a grid sequence. Find your memory span.
Reading Speed TestRead a short text, answer three questions, get your words per minute.
Reaction Time TestClick when the screen turns green. Five tries, average in milliseconds.
Schulte TableFind the numbers 1 to 25 in order. A classic attention and visual search drill.
Play the Stroop game every day
Brainura's Stroop Test game gets harder as you improve, and comes with 25 more short games for memory, attention and logic. No ads.
Free to install · no ads · no account needed
Sources
- Stroop, J. R. (1935). Studies of interference in serial verbal reactions. Journal of Experimental Psychology, 18(6), 643–662.
- MacLeod, C. M. (1991). Half a century of research on the Stroop effect: An integrative review. Psychological Bulletin, 109(2), 163–203.
- Diamond, A. (2013). Executive functions. Annual Review of Psychology, 64, 135–168.