Stroop test online
The word “RED” is printed in blue. Pick the colour of the ink – blue – not the word. Sounds easy, but it slows everyone down: reading happens automatically, and that is exactly what you have to filter out.
How it works
- 1Start – a colour word appears in an ink colour.
- 2Tap the ink colour, not what the word says.
- 3Sometimes word and colour match, sometimes not.
- 4As fast and accurately as you can – 24 trials, just over a minute. Keys 1–4 work too.
- 5Result: speed, errors and your Stroop effect – how much slower you are on mismatched pairs.
The effect
John Ridley Stroop described it in 1935: when word and colour don’t match, everyone responds more slowly and makes more mistakes. The gap between matching and mismatched pairs – the interference – shows how well you filter out distraction. Typical values are 50 to 150 milliseconds.
What it is good for
The Stroop test is a standard in psychology for measuring attentional control; fatigue and stress make the effect bigger. As training its everyday benefit is limited – as a check of your daily form, together with the reaction time test, it is revealing.
Sources: Stroop 1935
Frequently asked questions
Why am I slower on mismatched pairs?
Because reading happens automatically. Your brain first has to suppress the word you read.
Is it an intelligence test?
No. It measures one aspect of attention, not intelligence.
Is the test available in German?
Yes, on the German page the colour words are German.
More for “Concentration”
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- Schulte table onlineTap the numbers 1–25 in order as fast as you can: the Schulte table free in your browser, with timing and history.
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Exercises are no substitute for help if you've been feeling bad for a while. Talk to your university's counselling service. In a crisis: call your local emergency number or a crisis line in your country.