Stroop Effect (Wikipedia)
An encyclopedia article on the Stroop effect: the measurable delay in reaction time when people are asked to name the ink color of a color word printed in a conflicting color (e.g. naming the color of the word “red” printed in blue ink). John Ridley Stroop published the foundational 1935 study; the effect had been independently documented by Erich Jaensch in Germany in 1929. Wikipedia articles are continuously edited, so year above reflects the access date (2026-06-24), not a fixed publication year.
License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/
Key points
- The leading explanation (automaticity theory) is that reading is so practiced it happens automatically and consumes attentional resources that color-naming then has to compete for; three other explanations (processing-speed theory, selective-attention theory, parallel distributed processing) are also documented but less widely accepted.
- The classic task uses three stimulus types: color names printed in black, color names printed in an incongruent color, and plain colored squares — naming ink color is measurably slower and more error-prone for the incongruent condition than for the neutral ones.
- An emotional Stroop variant shows the same kind of interference happens with emotionally-loaded words, not just color words — suggesting the underlying mechanism is about competing automatic/salient associations generally, not color specifically.
- The article documents mostly clinical/diagnostic applications (measuring selective attention and processing speed, screening for ADHD and depression) rather than interface-design applications — it does not discuss icon/label mismatches, UI color conventions, or any other direct design case study.