Stroop Effect Test
A color word appears in a different ink color. Click the color of the ink, not the word it spells. Measure your focus when the two disagree.
Respond to the color you see, not the word.
How much does the Stroop effect slow you down?
Reading is faster and more automatic than naming a colour, so every mismatched trial forces an override. The time that override costs is the effect itself.
| Rating | Average time per correct answer | What it means |
|---|---|---|
| Elite | Under 700 ms | Strong suppression of the automatic reading response. |
| Fast | 700–900 ms | Quick colour naming with minimal interference cost. |
| AverageMost people | 900–1,200 ms | The usual range once the word and ink disagree. |
| Below average | 1,200–1,600 ms | Each trial needs a deliberate correction. |
| Slow | Over 1,600 ms | Reading is winning most trials before you can override it. |
Reading the numbers: The interference cost — the gap between mismatched and matching trials — normally runs 100–300 ms and never disappears entirely, even with practice. That durability is exactly why the task has stayed in use since 1935. Fatigue widens the gap noticeably, which makes this a decent self-check on how sharp you are right now.
A 1935 experiment you can run in a browser.
Word and ink disagree on purpose, and the delay that creates is the entire finding.
Word/ink conflict
The word and its ink color usually disagree.
20-trial round
A fixed run gives a comparable score.
Accuracy tracked
See correct answers out of the round.
Average response
Your mean answer time is measured.
Best score saved
Your highest correct count is stored locally.
Private by default
Answers and response times stay on your device.
Answering a Stroop trial.
Read nothing, name the colour — easier said than done.
Start the round
Click to begin the 20 trials.
Read the ink
A color word appears in a different ink.
Click the color
Choose the ink color, not the word.
Finish 20
Get your accuracy and average time.
What the Stroop test is used for.
A standard probe of selective attention that doubles as a fatigue check.
Selective attention
Measure how well you filter conflicting information.
Interference research
A clean demo of the classic Stroop effect.
Focus under distraction
Train overriding an automatic response.
Psychology demos
A ready-made classroom illustration.
Mental warm-up
Prime your focus before demanding work.
Compare sessions
Track your interference cost over time.
How the Stroop test works
A color word appears in a different ink color — for instance the word "RED" printed in blue. Click the button for the ink color you see, ignoring the word it spells. It sounds trivial, but reading is so automatic that the word fights your answer.
That conflict is the Stroop effect, and it measures selective attention and processing speed under interference — how well you suppress the automatic urge to read. After 20 trials you get your accuracy and average response time. Your best score is saved locally.
Stroop Test questions, answered.
What is the Stroop effect?
It's the delay in naming an ink color when the word spells a different color — for example the word 'RED' printed in blue. Reading is so automatic that it interferes with naming the color you see.
What does this test measure?
It measures selective attention and processing speed under interference: how well you can suppress the automatic urge to read the word and respond to the ink color instead.
Why is it harder than it looks?
Because reading is faster and more automatic than color naming, your brain has to actively override it every trial. That override costs time, and the cost grows when you're tired or rushing.
How can I get better at it?
Focus on the color and try to slightly blur the word, or narrow your attention to the ink. Practice reduces the interference somewhat, but the effect never fully disappears — that's what makes it a classic.
Tests closest to the Stroop Test test.
Tests that punish acting on autopilot: you have to override an automatic response to score well.