Stroop test
≈ 3 MIN · 4 PRACTICE + 40 TRIALS · Attention
What this is about
Reading cannot be switched off: asked to name the ink colour of a word, you read the word anyway — and when GREEN stands there in red ink, two processes collide. The difference in response times has been one of psychology’s most reliable measures of automatic versus controlled processing since 1935.
In the original, Stroop’s participants needed about 47 seconds longer for a hundred conflicting words than for a hundred colour patches — nearly half a second of surcharge per word, stable across days of practice.
How it runs
- Four practice trials, unscored.
- Block I: twenty trials, word and colour agree.
- Block II: twenty trials, word and colour conflict.
- Answer with keys 1–4 or the colour buttons; a fixation cross (500 ms) stands between trials; the clock starts the moment the word appears.
Runs entirely in your browser — nothing is transmitted or stored.
You can stop the run at any time.
Your finding
What it means
Limits of this experiment
- No calibrated display — screen and keyboard add unknown latency.
- One session, one device — daily form and practice effects are not averaged out.
- Forty trials separate conditions, not people.
- The first trial of each block is discarded — it carries the switch to the new condition; 19 per block are scored.
→ Case file 008 · KAHNEMAN→ Topic: Measurement and Method→ Glossary: Dual-process model