Stroop Color-Word Test
— Free Online
Three blocks, ~5 minutes. Instant interference score and percentile profile against published norms. No signup needed.
The three blocks
Color naming
Name the ink color of neutral symbols. Establishes your baseline color-naming speed before any competing word information is introduced.
Word reading
Read color words printed in matching ink. Captures your automatic reading speed — the prepotent response that the third block must inhibit.
Incongruent (interference)
Name the ink color while ignoring a conflicting color word. The classic Stroop conflict trial. The slowing relative to Block 1 is the Stroop Interference Effect — your executive inhibition score.
Common questions
How long does it take?
About five minutes. The task itself is three short blocks of trials with brief instructions in between. Most people finish in under six minutes including the calibration step.
Is it really free?
Yes. You can take the Stroop, see your reaction-time and accuracy by block, and read your interference score with no signup. The deeper clinician-style score report — percentile profile against published norms, validity indicators, block-by-block breakdown — is part of the clinician and researcher offering, set up by arrangement.
How accurate is an online Stroop test?
Browser-based reaction-time tasks are now well-validated for research and self-screening when implemented carefully. We calibrate to your monitor's refresh rate and use frame-locked stimulus presentation, so the timing precision is much closer to lab-grade than to a casual quiz. Any single administration is still a snapshot — sleep, caffeine, and distraction all move the score — so treat it as descriptive of one session, not a fixed trait.
Can I retake it?
Yes. Practice effects on the Stroop are modest but real, so the very first administration tends to be the most diagnostic. If you retake, expect a small speedup across all blocks; the interference effect itself is much more stable.
What's the difference between this and a clinical Stroop?
A clinical Stroop (Golden, 1978; D-KEFS Color-Word Interference) is administered in person by a clinician with stopwatch timing or paper-and-pencil sheets, and is interpreted alongside other neuropsychological tests as part of an evaluation. This online version uses the same paradigm — color naming, word reading, incongruent interference — but is self-administered, computer-timed, and intended for self-knowledge or research rather than clinical diagnosis.
Take the live task when it launches, or see what the report looks like now.