Stroop Test — Name the Ink Color, Not the Word
Click the button matching the INK color of the word, not what the word says. Score reaction time across 20 trials.
How to play
- Click Start to begin 20 Stroop trials.
- A color word appears, printed in a (usually different) ink color.
- Click the colored button that matches the INK color — ignore the word.
- Each correct answer scores a point; your reaction time is recorded.
- After 20 trials you see your score and average reaction in milliseconds.
The Stroop test measures cognitive interference. A color word is shown in an ink color that usually does not match. You must click the button for the INK color, not the word you read. The automatic urge to read the word slows you down — that delay is the Stroop effect.
How it works
The Stroop Test is one of psychology's most replicated demonstrations of cognitive interference. A colour word (like RED or BLUE) is displayed in an ink colour that may differ from the word's meaning — for example, the word BLUE printed in red ink. Your task is to click the button that matches the ink colour, not what the word says.
This is harder than it sounds because reading is a deeply automatic process. The brain processes the word's meaning almost reflexively and creates interference when that meaning conflicts with the colour you are actually trying to identify. This slowdown — called the Stroop effect — is measured in milliseconds and is a reliable indicator of executive attention and cognitive control.
The widget presents 20 trials and records your response time for each. Congruent trials (word and ink match) are used as baselines; incongruent trials (word and ink differ) typically take 100 to 300 milliseconds longer. Your average across both types and the gap between them are the key metrics.
The test is used in neuropsychological research, ADHD assessment, and as a warm-up exercise in cognitive training programmes. Playing it regularly can help you practise suppressing automatic responses — a skill linked to self-regulation and focused attention.
Worked example
Work through an incongruent trial correctly
- A word appears on screen — say, the word GREEN printed in yellow ink.
- Read the word automatically (you cannot help it), but immediately redirect your attention to the ink colour.
- Identify the ink: it is yellow.
- Click the YELLOW button, not the GREEN button.
- Your response time is logged; the next trial appears immediately.
Correct response recorded. Over 20 trials your average incongruent time will be measurably higher than your congruent time.
Common mistakes to avoid
- Clicking the button that spells the colour word instead of the button that matches the ink — the whole challenge is to override the word's meaning.
- Going too fast and mis-clicking: speed matters, but accuracy is the priority; an error is worse than a slightly slower correct response.
- Not taking the test seriously across all 20 trials — fatigue effects in the later trials are part of what the test measures, so consistent effort throughout is important.
Key terms
- Stroop effect
- The cognitive interference (and resulting slowdown) caused when the meaning of a written word conflicts with another attribute of that word, such as its ink colour.
- Congruent trial
- A trial where the ink colour and the word meaning match (e.g., the word RED in red ink); these are generally faster than incongruent trials.
- Incongruent trial
- A trial where the ink colour and word meaning differ (e.g., the word RED in blue ink); these show the Stroop interference effect.
Frequently asked questions
- What is the Stroop effect?
- Discovered by John Ridley Stroop in 1935, it's the delay in naming a color when the word spells a different color (e.g. the word 'RED' printed in blue ink). Reading is so automatic that it interferes with color naming.
- How is my score calculated?
- You get a point for each trial where you pick the correct ink color. Average reaction time across all 20 trials is also reported in milliseconds.