Stroop Test

It measures how well you can answer the task in front of you while ignoring a strong habit: reading. In 1935, John Ridley Stroop found that people took much longer to name the ink colors of conflicting color words (the word "red" printed in blue, for example) than to name plain patches of color [1]. That slowdown is called the Stroop effect, and it is one of the most studied findings in psychology [2].

Researchers use the Stroop task to study selective attention and the control of automatic responses [2].

• One word appears at a time (red, green, blue, yellow), printed in one of the same colors. Answer the ink color with the buttons or the keyboard.
• 4 practice words with feedback come first, then 40 counted words. In 50% of them the word matches its ink; in the rest it doesn't.
• If you don't answer within 3 seconds, the word counts as a miss. Leaving the page ends the run, because the test is timed.

• Time cost of mismatched words: your average time on mismatched words minus your average on matching words, right answers only. This is your Stroop effect. Smaller means the word got in your way less.
• Answered right: the share of all counted words you answered correctly. Going faster usually costs accuracy, so look at both numbers together.

This version shows one word at a time and you answer with buttons, like most computer versions. Stroop's own version used printed cards read aloud, so the numbers are not comparable with his.

If you have trouble telling some of these colors apart, for example red and green, this test can't measure you fairly. Your device's color settings, night mode or a dark-mode filter can also change how the colors look. Practice with the task can change your numbers too, so compare with your own earlier runs.

For another test of stopping an automatic response, try the go/no-go test.