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The Debunker: Are There “Left-Brained” and “Right-Brained” People?

by Ken Jennings

Did you know that the second week of March is Brain Awareness Week around the globe? You didn’t? You weren’t aware of your brain? Conscious of your consciousness? Well, get with the program. March is perhaps the brainiest month of the year—it’s also when we celebrate the 1879 birthday of famous smarty-pants Albert Einstein, and the 1946 beginning of Mensa intelligence testing. But it turns out people will believe just about anything they hear about what’s going up between their ears. We’ve asked Ken Jennings to fact-check some particularly lame-brained misconceptions about gray matter.

The Debunker: Are There “Left-Brained” and “Right-Brained” People?

Your buttoned-down computer programmer friend Gary is detail-oriented and analytical. Not long ago, he would have carried a slide rule with him at all times in his jacket pocket. “Left-brained!” you announce knowingly. But your free spirit friend Maya is creative and intuitive. She’s written poetry since third grade and has recently taken up painting. Regardless of weather, she is probably wearing a scarf right now. “Right-brained!” you decide.

Well, you’re wrong on both counts. It’s true that our brain is divided into two halves, or hemispheres, joined only by a dense bundle of nerve fibers called the corpus callosum. And there is some degree of what scientists call lateralization within the brain: the left hemisphere is where speech arises in most people, for example. But the asymmetries within the brain aren’t well-understood, and they change over time as people age.

Most critically, there is no clear-cut distinction between one “logical” hemisphere and one “creative” one. Brain scans of over 1,000 patients studied at the University of Utah in 2013 don’t reveal any difference in neural traffic: all people of all personality types have essentially the same amount of connectedness on both halves of their brain. And injury to either hemisphere can impair certain skills (math, for example) equally. The new thinking is that all complicated brain tasks, whether analytical or creative, require both halves to be cranking and even collaborating. Anyone who thinks a certain kind of thinking or personality is “left” or “right” is definitely not “right.” To quote Obi-Wan Kenobi, only a Sith deals in absolutes.

Quick Quiz: Judy Collins’ biggest hit, the song “Both Sides, Now” was actually written by what other singer-songwriter?

Ken Jennings is the author of Because I Said So!, Brainiac, Ken Jennings's Trivia Almanac, and Maphead. He's also the proud owner of an underwhelming Bag o' Crap. Follow him at or on Twitter as @KenJennings.