What is the Stroop test?
The Stroop test is a classic experiment in attention. Color names flash up in mismatched ink, the word GREEN in yellow for example, and you have to name the ink, not the word. Your brain reads automatically, so every clash slows you down a little.
Take the Stroop effect test online free here. It takes about a minute, and you can try again to beat your time.
The history of the Stroop effect
The test is named after John Ridley Stroop, an American psychologist who published the classic experiment in 1935 in the Journal of Experimental Psychology. He showed that people take longer to name the ink color of a word when the word itself names a different color. Reading is so automatic for adults that the word pushes in, and you have to hold it back to give the right answer.
The Stroop effect became one of the most studied findings in psychology. Researchers use versions of it to study attention, self-control and how the brain handles conflicting information.
How this test works
Color names appear one at a time, and you tap the button for the color of the ink, not the word. In the Colors clash round, the ink and the word never match. In the Colors match round they always do. Comparing your times in the two rounds shows how much the clash slows you down: that gap is your Stroop effect.
Tips for a better score
- Focus on one letter. Looking at the middle of the word, and paying attention to its color, helps stop you reading it.
- Slow down to be accurate. A wrong answer costs more than a fraction of a second.
- Practice both rounds. Your matched round is your baseline. The smaller the gap, the better your control.
Is it a medical test?
No. Clinical versions of the Stroop test are used by professionals as part of a wider assessment, but this online version is a game for practice and fun. If you enjoy it, the Schulte table is another short test of attention.
How to play Stroop Test
- A color word appears, such as RED, printed in a different ink color.
- Choose the ink color, not the word you read.
- Answer all 20 words as quickly as you can.
- Your score is your total time and the number of correct answers.
Stroop Test tips
Blur the word slightly
Focusing on the shape of the letters rather than reading them helps many people see the color first.
Accuracy before speed
A wrong answer costs more than a short pause. Start steady and speed up once you feel in control.
Practice both rounds
Try a round where words and colors match, then one where they clash. The gap between your two times is your personal Stroop effect.
Frequently asked questions
What is the Stroop effect?
It is the delay you feel when a word's meaning and its ink color clash, for example BLUE printed in red. Reading is so automatic that it gets in the way of naming the color.
Who discovered the Stroop effect?
The American psychologist John Ridley Stroop described it in 1935. It is still one of the best-known experiments in psychology.
Does this test diagnose anything?
No. It is a fun attention exercise, not a medical or psychological assessment.
