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Stroop Test

Read the word, or name the color?

You'll see a color word painted in another color. Click the color of the text, not the word itself.
About

Classic cognitive interference test. Click the matching color, not the word. Measures executive function.

The Zehano Stroop test runs the classic colour-word interference task in your browser. You see a colour word (RED, BLUE, GREEN) printed in a different ink colour, and you must name the ink, not the word. The slowdown between matching and conflicting trials is your Stroop interference, a clean measure of cognitive control.

How to use the Stroop Test

  1. Read the prompt. A word appears in a coloured ink. Sometimes word and colour match, sometimes they conflict.
  2. Name the ink colour. Click the button matching the ink colour, not the word. Speed and accuracy both matter.
  3. Complete the round. Move through a set of trials. The test mixes congruent and incongruent items.
  4. See your interference score. The difference between your average congruent and incongruent times is your Stroop effect.
  5. Compare across sessions. Your best is saved. Smaller interference means stronger cognitive control today.

Benefits

  • Tests executive function. A standard measure of inhibitory control used in clinical neuropsychology.
  • Sensitive to state. Performance drops noticeably with sleep loss, stress, and depression.
  • Quick to take. A round takes about a minute. Easy to use as a daily check-in.
  • Free and private. No signup. Scores stored locally in your browser.

The science

The Stroop effect was first described by John Ridley Stroop in 1935 and has become one of the most reliably replicated findings in cognitive psychology. Naming the colour of conflicting words takes adults roughly 100 to 300 milliseconds longer than naming the colour of matching words. The mechanism is conflict between two automatic processes: reading (very automatic for literate adults) and colour naming (less automatic). Brain imaging studies link the conflict to the anterior cingulate cortex, which monitors competition between responses, and the dorsolateral prefrontal cortex, which maintains the task goal.

Bilingual people often show smaller Stroop interference, attributed to lifelong practice in inhibiting one language while using another. The effect is modest and contested.

Tips for best results

  • Test when well-rested for your best baseline.
  • Keep your eyes on the centre of the screen, not pre-scanning the buttons.
  • Accuracy matters: a single error often takes longer to recover from than two slow trials.
  • Compare across different times of day to see your circadian rhythm in action.

FAQ

What does the Stroop test measure?+
Selective attention and inhibitory control, two components of executive function. People who score better tend to be more able to override automatic responses.
Why am I slower when the word and colour conflict?+
Reading is faster and more automatic than colour naming. The brain has to actively suppress the reading response to produce the colour name, which takes time.
Can I train myself to do better on the Stroop test?+
Yes, on the specific task. Transfer to broader cognitive function is small and contested. Better sleep and aerobic exercise produce more reliable improvements.
Why is the Stroop test used clinically?+
It is sensitive to executive function changes that come with traumatic brain injury, dementia, and ADHD. It is used as part of broader assessments, not as a stand-alone diagnostic.
Is this Stroop test free?+
Yes. All Zehano tools are free, with no signup or ads.

Keep learning

Article · 8 min
The Stroop Effect: Why Your Brain Trips Over Coloured Words
Ammar Rashid
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