Did you know that it’s rumored that a simple game helped counterintelligence agents discover Russian Spies? For decades, this classic psychology experiment based in a simple, funny, yet devilish game continues to demonstrate how play reveals the inner working of our minds.
Try this. Read the following set of words out loud:
Red Blue Yellow Green Purple
Piece of cake, right? Now, (and here’s the brain-teaser) say out loud the color of the text in each word:
Red Blue Yellow Green Purple
Um, er, ahh, how did you do? Did the second set slow you down? Did it slow you way down? Well it slows almost everybody down. To me the game seems like the verbal/visual equivalent of the rub-your-stomach-and-pat-your-head trick. The harder you try to get it right, the more you stutter and fumble.
It was this hesitation that caught the ear of an American psychologist, John Ridley Stroop, in 1935. American and German psychologists had long been interested in measuring how fast impulses traveled through the nervous system, and they were particularly curious about those factors that could inhibit or interfere with the transmission. Stroop noted that we have no trouble saying the name for the color when it is congruent with the ink color—when red is printed in red. But it takes longer to name the ink color when the word doesn’t match—when the word “red” for example is, incongruously, printed in blue. (Black ink doesn’t seem to make a difference.) With this switcheroo you’re not just slowed down, you’re prone to error. You’re more likely to make a mistake and say “red” when the word is printed in blue. Psychologists, who have replicated the experiment in different versions many hundreds of times, now call the error-prone hesitation the “Stroop Effect.”
Psychologists like the way that the Stroop Effect messes with your mind because how the game interferes with the normal process helps them understand the normal process. So what is the normal process?
Ordinarily when we read the word “red” we think of the color red. We associate the text with the color naturally and automatically. Interfere with that usual semantic association by printing red in blue and the visual stimulus interferes with our ordinary association. When you play the game you are asking your brain to override the powerful, accustomed stimulus. Learning to read constructs neural pathways in your brain that make it very hard to switch off the impulse to read the word and attend to the color instead.
Some claim that playing with the Stroop Effect isn’t just a brain-teaser; they say that it’s so difficult that it’s a brain exerciser. The Nintendo DS Brain Age: Train Your Brain in Minutes a Day promises to “give your brain a workout” with puzzles, math games, and versions of Stroop Task. Or you can practice mental calisthenics with the Stroop Effect online.
Other mischievous visual games call out the Stroop Effects: mislabeling an image, or mixing up left and right.
A friend of mine who recently traveled to Albania gave me another example of the hilarious effects of a Stroop-like Effect. The custom of nodding yes is reversed there—Albanians shake their heads to agree and nod to say no. And he found this reversal so hard to follow in practice that obliging, but bemused, waiters brought him increasingly larger tankards of ale and bigger slabs of lamb that he thought he’d refused.
So, how does the Stroop Effect relate to the great games of espionage and counterespionage? Deep cover spies operating in the U.S. assume a new identity, dress like the natives, take on their mannerisms, and master their foreign popular culture—even convincingly root for the Philadelphia Phillies. Foreign spy-school masters teach trainees to say “no way Jose” plausibly, and “Buddy, I tell you what,” just like other Americans. But spy-masters can’t teach even their best pupils a way to defeat the Stroop Effect. During the Cold War, American interrogators are reputed to have trapped native Russian-speaking spies by presenting them with a Stroop Effect task—take for example the word красный, which means “red.” Show it to an American and you’ll get no reaction at all. But counterspies have their ways of detecting the hesitation, the momentary pause that grips deep cover agents when the word красный appears in blue. In that tiny dithering interval the Stroop Effect betrays them.