Stroop Effect
A demonstration of interference in the reaction time of a task, particularly the delayed reaction times when the color of the word doesn't match the name of the word.
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Origin
Named for psychologist John Ridley Stroop, who described the interference effect in his 1935 doctoral dissertation at George Peabody College (now part of Vanderbilt University) and published the results in the Journal of Experimental Psychology that same year. The work built on earlier colour-word reading-time experiments by James McKeen Cattell in the 1880s, but Stroop was the first to document the asymmetric interference. The paper has since been cited over 10,000 times, making it one of the most cited works in experimental psychology.
Updated February 22, 2026