Executive Function
Stroop Color-Word Test
Quantify interference cost and cognitive inhibition with a modern browser-native Stroop workflow.
4-6 minTimed: desktop or laptop with a mouse or trackpad
Free to start: 10 free participants per account, then $0.99 per participant for academic research, or any yearly plan. Try it here first, with no account.
- Papers, 2021 to 2025
- 4,956
- Evidence grade
- A
- Registered clinical studies
- 1,929
Example data
One session, scored by the code that scores your study's sessions.
Stroop Effect
127.1ms
Incongruent RT minus congruent RT.
Quality check: valid60 scored trials
- Congruent RT
- 654.3 ms
- Incongruent RT
- 781.3 ms
- Interference Score
- 0.17
- Congruent Accuracy
- 95.8%
- Incongruent Accuracy
- 91.7%
- Congruent
- Incongruent
- Neutral
- Mean
- Wrong answer
Trial file
The first 6 of 68 rows, with the column names of your study's export.
| participant_id | test_slug | test_version | scoring_version | trial_index | trial_type | response | rt | correct | time_elapsed | condition | correct_response | ink_color | plugin_version | run_id | task | word |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| simulated | stroop | 1.0.1 | 1.0.1 | 0 | html-keyboard-response | g | 819 | true | 3719 | incongruent | g | green | 2.1.0 | example-run | stroop_practice | RED |
| simulated | stroop | 1.0.1 | 1.0.1 | 1 | html-keyboard-response | g | 576 | true | 4795 | congruent | g | green | 2.1.0 | example-run | stroop_practice | GREEN |
| simulated | stroop | 1.0.1 | 1.0.1 | 2 | html-keyboard-response | b | 659 | true | 5954 | neutral | b | blue | 2.1.0 | example-run | stroop_practice | XXXX |
| simulated | stroop | 1.0.1 | 1.0.1 | 3 | html-keyboard-response | y | 666 | false | 7120 | neutral | g | green | 2.1.0 | example-run | stroop_practice | XXXX |
| simulated | stroop | 1.0.1 | 1.0.1 | 4 | html-keyboard-response | b | 801 | true | 8421 | incongruent | b | blue | 2.1.0 | example-run | stroop_practice | RED |
| simulated | stroop | 1.0.1 | 1.0.1 | 5 | html-keyboard-response | r | 643 | true | 9564 | neutral | r | red | 2.1.0 | example-run | stroop_practice | XXXX |
What it measures
Measures cognitive inhibition by asking participants to identify the ink color of color words, creating interference between reading and color naming.
Constructs
- Cognitive inhibition
- Automaticity interference
- Executive control
- Conflict resolution
- Processing speed under interference
Research uses
- Frontal lobe dysfunction assessment
- ADHD executive function evaluation
- Dementia screening
- Schizophrenia cognitive profiling
- Concussion recovery monitoring
How the paradigm works
The Stroop Color-Word Test is a classic measure of cognitive inhibition and the automaticity of reading. Participants see color words (RED, GREEN, BLUE, YELLOW) displayed in colored ink and must identify the ink color while suppressing the automatic tendency to read the word. On congruent trials, the word matches the ink color (RED in red ink). On incongruent trials, they conflict (RED in blue ink). Neutral trials use non-color words (XXXX) in colored ink.
More about the paradigm
The Stroop effect (incongruent RT minus congruent RT) reflects the processing cost of inhibiting the overlearned reading response. The interference score normalizes this cost against the neutral baseline, providing a ratio-based measure of executive control efficiency.
The Stroop test engages the anterior cingulate cortex for conflict detection and the left inferior frontal gyrus for response inhibition. It is one of the most widely used neuropsychological tests, with over 700 published studies establishing its sensitivity to frontal lobe dysfunction.
Scores
- Congruent RTms
- Average RT when word meaning matches ink color.
- Lower is better
- Incongruent RTms
- Average RT when word meaning conflicts with ink color.
- Lower is better
- Stroop Effectms
- Incongruent RT minus congruent RT. Primary measure of interference cost from automaticity.
- Lower is better
- Interference Scorescore
- (Incongruent RT - Neutral RT) / Neutral RT. Ratio-based measure controlling for baseline processing speed.
- Lower is better
- Congruent Accuracy%
- Proportion correct on congruent trials.
- Higher is better
- Incongruent Accuracy%
- Proportion correct on incongruent trials. More sensitive than congruent accuracy.
- Higher is better
Use and evidence
4,956 papers from 2021 to 2025 name this task in their title or abstract, up 14% compared with 2016 to 2020. That ranks it 4 of 582 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 1,339 |
| 2024 | 1,041 |
| 2023 | 911 |
| 2022 | 811 |
| 2021 | 854 |
| 2020 | 878 |
| 2019 | 950 |
| 2018 | 855 |
| 2017 | 825 |
| 2016 | 829 |
| 2015 | 803 |
| 2014 | 728 |
| 2013 | 745 |
| 2012 | 676 |
| 2011 | 598 |
| 2010 | 550 |
| 2009 | 456 |
| 2008 | 373 |
| 2007 | 357 |
| 2006 | 357 |
| 2005 | 301 |
| 2004 | 253 |
| 2003 | 205 |
| 2002 | 214 |
| 2001 | 160 |
| 2000 | 177 |
Use grade A
1,000 or more papers from 2021 to 2025.
Evidence grade A
At least 25 papers report its test-retest reliability and at least 25 registered clinical studies use it as an outcome.
- Papers on test-retest reliability
- 151
- Papers on reliability or validity
- 1,204
- Registered clinical studies using it as an outcome
- 1,929
Measured on ConductCognition
Pooled across the studies that feed our platform norms, by device group. A figure needs 50 or more people.
No pooled figure yet.
How the grades work
Use: A is 1,000 or more papers from 2021 to 2025, B 300 to 999, C 100 to 299, D 30 to 99 and E fewer than 30. Evidence: A means at least 25 papers report its test-retest reliability and at least 25 registered clinical studies use it as an outcome; B, at least 8 test-retest papers, and either 5 registered clinical studies or 150 reliability or validity papers; C, at least 2 test-retest papers, 30 reliability or validity papers or 3 registered clinical studies; D, little published measurement evidence found. The counts measure use. They include every paper that names the task in its title or abstract. Grades describe the published research on this task, not ConductCognition's version of it.
Source: ConductCognition test census 0.39.0, counted 31 October 2026 from OpenAlex and ClinicalTrials.gov.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scored rows: stroop_test, four color keys (chance 25%, 15 trials per key). Below chance invalidates and not above chance is flagged. One key on 90% of answers invalidates when accuracy is not above chance. No response window; responses under 100 ms follow the timed-test rule.
Why these rules
Accuracy significantly below chance (one-sided exact test, p < .05) cannot come from guessing; it means the response mapping was reversed or the task was not followed (Slick, Sherman and Iverson 1999 treat below-chance forced-choice performance as definite response bias). Chance-level accuracy can be a real result in impaired participants, so it is only flagged. One option on at least 90% of answered trials, when the correct options are balanced and accuracy is not above chance, means the answers did not depend on the items (the task counterpart of long-string responding in surveys; Curran 2016). Missed responses and responses under 100 ms keep the platform's timed-test rule: more than max(3, 25%) missed responses or more than max(2, 20%) responses under 100 ms invalidate, and any is flagged. A response under 100 ms cannot be a reaction to the stimulus.
Running this test
Settings you can change
| Setting | Standard | Allowed |
|---|---|---|
| Congruent trials | 24 | 12 to 48 |
| Incongruent trials | 24 | 12 to 48 |
Yearly plans can change settings within these limits. Free and pay-as-you-go studies use the standard settings.
Need a setting this test does not have?
Devices and languages
- Timed test: participants need a desktop or laptop with a mouse or trackpad. Participant devices
- Languages: English, Spanish, French, German, Italian, Portuguese (Brazil), Chinese (Simplified) and Japanese.
- Available on: Every plan, including the free plan.
- Recruiting online? See the setup guides for Prolific, Sona Systems, CloudResearch Connect and Qualtrics.
Included in these batteries
Each battery runs this test with others in a fixed order, with standard settings.
- Pilot Screening Battery4 tests, 15 minutes per participant
- Executive Control Battery4 tests, 18 minutes per participant
Cite and describe
Participants completed the Stroop Color-Word Test in a web browser (ConductCognition task version 1.0.1, scoring version 1.0.1; Stroop, 1935), with the standard settings (congruent trials: 24; incongruent trials: 24). The main score was Stroop effect (incongruent RT minus congruent RT).
Paradigm source: Stroop (1935).
ConductCognition versions: task version 1.0.1, scoring version 1.0.1. Every export records the versions each session used, for a methods section.
Source papers
- Van der Elst W, Van Boxtel MPJ, Van Breukelen GJP, Jolles J (2006). The Stroop color-word test: influence of age, sex, and education; and normative data for a large sample across the adult age range. Assessment, 13(1):62-79.Paradigm source
Questions
How long does the Stroop Color-Word Test take?
About 4 to 6 minutes, as listed in the test library.
What device does a participant need?
Timed test: participants need a desktop or laptop with a mouse or trackpad. The browser must be Chrome, Edge, Firefox or Safari.
What scores does it produce?
Congruent RT, Incongruent RT, Stroop Effect, Interference Score, Congruent Accuracy and Incongruent Accuracy. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Stroop Color-Word Test used in research?
4,956 papers from 2021 to 2025 name it in their title or abstract, up 14% compared with 2016 to 2020. That ranks it 4 of 582 test families in the ConductCognition test census (use grade A). Source: ConductCognition test census 0.39.0, counted 31 October 2026 from OpenAlex and ClinicalTrials.gov.
How much reliability evidence does the Stroop Color-Word Test have?
In the published research, 151 papers report its test-retest reliability and 1,929 registered clinical studies use it as an outcome (evidence grade A in the ConductCognition test census).
Which settings can a researcher change?
Congruent trials (12 to 48) and incongruent trials (12 to 48). Settings can be changed on yearly plans; free and pay-as-you-go studies use the standard settings.
Which languages can participants use?
Participants can take this test in English, Spanish, French, German, Italian, Portuguese (Brazil), Chinese (Simplified) and Japanese, with its words in the same language. English is on every plan, and the other languages come with yearly plans. Have a native speaker read the machine-translated text before launch.
Is this a clinical test?
No. ConductCognition is for research use only. It runs, scores and exports the test; clinical interpretation is outside the platform.
Every test: the full test list.
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