Free online cognitive control test
Stroop Test
Take the Stroop Test: name the color of the text, not the word itself. This classic psychology test measures cognitive flexibility and processing speed. Free, no signup required.
Reference range
700-900ms
Fast range
<500ms
The signal
About Stroop Test
The Stroop Test is one of the most famous experiments in cognitive psychology, first published by John Ridley Stroop in 1935. A color word (like 'RED') is displayed in a different ink color (like blue text). You must identify the color of the text, not read the word. This creates cognitive interference because reading is automatic, forcing your brain to inhibit the dominant response - a key measure of executive function and cognitive flexibility.
A simple loop
How to play
Follow the same short sequence each time so the score stays easy to understand.
- 01A color word appears on screen in a colored font
- 02Identify the COLOR of the text, not what the word says
- 03Select the correct color from the four buttons below
- 04Respond as quickly and accurately as possible
- 05Complete 30 rounds - your average response time is your score
What it trains
Benefits
- Measure your cognitive flexibility and inhibitory control
- Train executive function and attention management
- Assess processing speed under cognitive interference
- Build the ability to suppress automatic responses
- Track improvements in cognitive control over time
Make the next rep useful
Tips for better scores
- Focus on the ink color, try to avoid reading the word
- Peripheral vision can help - blur your focus slightly
- Don't rush - accuracy matters more than raw speed
- Practice makes the interference effect weaker over time
- This test is harder when tired - use it to gauge alertness
Keep exploring
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Context
Learn more
Go deeper on the skill, then return when you are ready for another clean baseline.
Keep the signal moving
Go beyond one good score.
Unlimited practice across all 12 tests, so your baseline gets clearer with every session.
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Questions
Frequently asked questions
What does the Stroop Test measure?+
The Stroop Test primarily measures cognitive flexibility (ability to shift between mental tasks), inhibitory control (ability to suppress automatic responses), and processing speed. It's widely used in clinical neuropsychology to assess executive function and is often included in ADHD evaluations.
Why is the Stroop Test so hard?+
Reading is an automatic process for literate adults - your brain reads the word before you can stop it. When the word conflicts with the ink color, your brain must inhibit the automatic reading response and redirect attention to the color, which takes extra processing time (the 'Stroop interference effect').
Is the Stroop Effect used in clinical settings?+
Yes, the Stroop Test is one of the most widely used neuropsychological assessments. It's used to evaluate executive function in conditions including ADHD, traumatic brain injury, dementia, depression, and schizophrenia. Performance changes can indicate neurological or cognitive issues.
Can practice reduce the Stroop Effect?+
Yes, but only partially. With practice, your response times improve and the interference effect decreases, but it never fully disappears in healthy adults. This is because reading remains automatic. The improvement comes from stronger inhibitory control, which transfers to other tasks requiring cognitive flexibility.