Stroop Test

The classic Stroop test: a color word is printed in a different ink color, and you have to name the ink color as fast as you can, not read the word. 24 trials, congruent (word and ink match) and incongruent mixed together. Shows the Stroop interference — the reaction-time gap between matching and mismatching stimuli — and your accuracy.

Tap the box or press Enter to start

How to do it

  • 24 trials. A color word appears, printed in one of four ink colors — press the button or key 1–4 for the INK color, not the word you read.
  • Congruent trials (word and ink match) and incongruent ones are mixed in random order.
  • This test relies on color perception — if you cannot distinguish the colors used, the result will not be meaningful.
  • This is a simplified online version with buttons. A full clinical attention assessment is done by a specialist.

Frequently asked questions

What is the Stroop test?

A classic cognitive-psychology task: a color word is shown in a different ink color, and you have to name the ink color while ignoring the word itself. It measures selective attention and cognitive flexibility — your ability to suppress automatic word reading in favor of a less obvious feature (color).

How do I read the result — what does interference mean?

Stroop interference is the difference between your median reaction time on incongruent trials (word and ink don't match) and on congruent trials (word and ink match), in milliseconds. A positive number means you answered slower on mismatched stimuli — the conflict between word and color slows the response. This simplified online version has no verified norm to compare against — compare your result with your own past attempts, on the same device and around the same time of day.

Why am I slower when the word and color don't match?

When the printed word names one color and the ink is another, that's a conflict — you have to name the color while suppressing the urge to read the word. That's the Stroop effect: resolving the conflict takes extra time, so incongruent trials run slower on average than congruent ones.

Is this the same as the clinical Stroop test?

No. This is a simplified online version with buttons — a quick self-check. A full clinical assessment of attention and cognitive flexibility is done by a specialist using a standardized protocol.

Can I track my result over time?

Yes. In the Health OS app, the Stroop test is available as a cognitive_test widget and stores the interference value (the cognitive_stroop_interference_ms metric) alongside your sleep data, so you can watch it move day to day.

Track your Stroop interference in the app → Reaction time test (PVT) →