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Brain Size and IQ

May 25, 2006

Is a bigger brain better?


Are bigger brains smarter? I’m Bob Hirshon and this is Science Update.

Listener Roger Daltry of Fort Lauderdale, Florida, called to ask whether there’s a relationship between the size of your brain and how smart you are. We turned to child psychiatrist Judith Rapoport of the National Institute of Mental Health. She says, yes, studies have found a tiny correlation between brain size and IQ. But it’s so weak that you couldn’t possibly guess people’s IQs by measuring their brains.

JUDITH RAPOPORT (National Institute of Mental Health):
People’s brains vary enormously. And people with the same height and weight and IQ can have brains that vary by as much as 70 percent.

She adds that the sizes of certain parts of the brain seem to be more important than the size overall. If you have a brainy science question, call us at 1-800-whyisit. If we use it on the air, you’ll win a Science Update mug. I’m Bob Hirshon, for AAAS, the science society.