Most of us believe we can control what pieces of information influence our decisions. But can we? The Stroop Test suggests no.


NARRATOR: There’s a simple test that’s been making fools of us since the 1930s. Can you beat it?

You’ll see words printed in different colors. Just name the color of each word you see, as fast as you can. Don’t read the word, just name the color of the letters. For example: yellow, blue, green, red.

Got it? Try it for yourself. Ready? Go!

[The words “yellow,” “green,” “blue,” and “red” appear one at a time, with the color of the text matching the name of the color: for instance, the word “yellow” appears in yellow text; “green” in green text, etc. Each word appears several times in random order.]

Pretty easy, right?

Now that you know what you’re doing, try it again with one small change. Remember: name the ink color, not the word. Ready? Go!

[The color words (“yellow,” “green,” “blue,” and “red”) appear again, except the color of the text now does not match the name of the color: for instance, the word “blue” appears in green text; “green” in blue text, “yellow” in red text, etc. Several word/color combinations appear in random order.]

Was that just as easy? No. But why?

It’s because naming colors may be easy, but reading is easier. Reading is automatic. It’s effortless. We can’t NOT read – and we do it all the time. So when the word BLUE matches the color BLUE, it’s easy to do the task perfectly. But when the two don’t match, suddenly, we take longer. We make more mistakes. It’s hard.

What you just experienced is the Stroop Effect, named for psychologist J. Ridley Stroop. But its effects aren’t limited to the psychology laboratory. In fact, it’s rumored that this test was used by Americans during the Cold War to catch Russian spies. Here’s how. The agents were asked to do the Stroop Task… but in Russian. The Cyrillic characters meant nothing to the American agents, so nothing stopped them from simply rattling off the right answers. But the spies, who could read Russian — they couldn’t ignore the words, so they slowed down, and they stumbled. And this revealed their true identities.

This is an interesting story, but it also teaches us something important about decision-making… even if we’re not Russian spies. Once information is in front of us, we process it — even if it’s irrelevant, misleading, or even wrong. So think about this: if having even two variables makes our job harder, what happens when there are 5, 10, even hundreds of variables in play, for instance when we evaluate people?

It’s commonly argued that without television, John F. Kennedy may not have become the 35th President of the United States. People who watched his debate with Richard Nixon tended to vote for the younger, traditionally attractive Kennedy. But the people who listened to the debate tended to vote for Nixon, who sounded more traditionally Presidential.

RICHARD NIXON: We know the way to progress, and I think first of all, our own record proves that we know the way.

NARRATOR: Our decisions shouldn’t hinge on whether information is seen or heard. But this debate showed that seemingly irrelevant features do matter — even in key decisions like voting.

So what can we do to make our decisions better?

Let’s start with the Stroop Test itself. When people try to beat the test, the first thing they often do is squint. This blurs the word and puts the focus on the color. Smart.

We can do this metaphorically, too. In the 1970s and 80s, American symphony orchestras began using blind auditions to filter out the information they didn’t need. So the musicians played. The judges judged. But between them now was a curtain that kept the focus on the music instead of the musician. Over the next 25 years, the number of women musicians in major orchestras skyrocketed. Their chances of being hired had increased by 25%.

This is a template for how we can outsmart our own minds.

One: acknowledge that you too can be “Strooped.” Our world is fast-paced and rich with information, so we can’t just say, “Oh, I’ll ignore that.”

Two: don’t assume that more information is better. Strange as it may sound, consider saying “please send me the data without x, y, or z.” Remove names from resumes or graded assignments. Make evaluations before knowing anyone else’s opinion.

Each of these strategies takes work, but sometimes you need to squint to see more clearly. Whether you’re looking for spies or your next employee, you’ll do it better if you focus on just what matters.


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Key takeaways from this module

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Extra materials if you want to learn more


Frank Stanton, the then-president of CBS, said of the Kennedy-Nixon debate: “Kennedy was bronzed beautifully… Nixon looked like death.” The legendary debate changed the face of political media strategy, but was it warranted? A 2003 study by political scientist James Druckman suggests, yes. People were significantly more likely to think Kennedy “won” the debate when they watched it versus listened to it.

Colors are one thing, but our decisions can also be influenced by something as insignificant as a single letter – whether we’re aware of it or not. Watch this video about how José Zamora dropped a single letter to gain a title, and read more about the research that shows how names can Stroop us.


Baumeister, R. F., & Tierney, J. (2011). Willpower: Rediscovering the Greatest Human Strength. Penguin.

Goldin, C., & Rouse, C. (2000). Orchestrating impartiality: The impact of” blind” auditions on female musicians. American Economic Review90(4), 715-741.

MacLeod, C. M. (1991). Half a century of research on the Stroop Effect: An integrative review. Psychological Bulletin, 109(2), 163-203.

Stroop, J. R. (1935). Studies of interference in serial verbal reactions. Journal of Experimental Psychology18(6), 643.


Strooped! was created and developed by Mahzarin Banaji, Olivia Kang, Kirsten Morehouse, and Evan Younger with support from PwC, Johnson & Johnson, and Harvard University.

Special thanks to the Bok Center’s Learning Lab Studio at Harvard University.

Narration by Olivia Kang

Animation & Editing by Evan Younger

Artwork by Olivia Kang

Assistant: Theodora Mautz

Music by J.S. Bach (performed by Advent Chamber Orchestra) and Olive Musique, Ben Beiny, Immersive Music, and Allegory Musia via Premium Beat

John F. Kennedy footage by CBS via JFK Library