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Public Domain · 1935

Stroop Color-Word Test: Most-cited cognitive test ever

The single most-cited cognitive test in history. Subjects name the COLOR of a printed word when the word itself is a different color name (e.g., the word "RED" printed in blue ink). The interference effect (delay in naming the color) is robust, universal, and reveals executive function/cognitive control. Used in over 700 published studies.

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About the Stroop Color-Word Test

In 1935 J.R. Stroop showed that naming the ink color of a word like "BLUE" printed in red ink took dramatically longer than naming the color of a neutral stimulus (XXXX in red ink). The interference - now called the Stroop effect - is one of the most robust findings in psychology. Every neurologically normal adult shows it, in every language tested, with effect sizes large enough to detect in tiny samples.

The interference comes from automatic word reading conflicting with the goal-directed color naming. Resolving this conflict requires executive control - specifically, the prefrontal cortex inhibiting the dominant reading response and selecting the weaker color-naming response. Stroop test performance correlates with frontal lobe function and degrades in conditions affecting the prefrontal cortex: ADHD, schizophrenia, Alzheimer's, traumatic brain injury.

The test has spawned thousands of variants (emotional Stroop, counting Stroop, spatial Stroop) and remains in widespread clinical and research use. It is included in many neuropsychological batteries (e.g., the Delis-Kaplan Executive Function System). For a 90-year-old test, it is remarkably untouched - the original 3-condition design (word reading, color naming, incongruent color-word) remains standard.

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Stroop Color-Word Test (1935): the most-cited cognitive test in history. In the original, subjects name the INK COLOR of words printed in conflicting colors. Web-adapted version below: each item describes a word printed in a specific ink color; pick the COLOR (ignore the word). Tests cognitive control and prefrontal function.

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About these items: These Stroop Color-Word Test items are originally-written reconstructions in the tradition of the original 1935 test, NOT verbatim copies of the historical items. Where the original is a 1-on-1 oral or physical-apparatus test (e.g., examiner shows a card, child draws a shape), we have adapted the format to self-administered multiple choice. See the original source for the authentic 1935-era items in their original administration format.

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The following are legitimate free or borrowable full-text sources for this test or its primary documentation:

Source

All test materials and historical content on this page are transcribed from:

Stroop, J.R. (1935). Studies of interference in serial verbal reactions. Journal of Experimental Psychology, 18(6), 643-662.

John Ridley Stroop (1897-1973) was a doctoral student at George Peabody College when he conducted the experiments. His 1935 paper has been cited over 17,000 times - one of the most-cited papers in all of psychology. Read it on Internet Archive: https://psycnet.apa.org/record/1936-01863-001.

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