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Shrinking Brains

August 30, 2011

Our brains shrink by up to 15% over our lifetimes, but those of chimpanzees do not.



Our incredible shrinking brains…I’m Bob Hirshon and this is Science Update.

Between young adulthood and old age, our brains can shrink by up to 15%. But our closest living relatives, the chimpanzees, don’t lose brain volume over time. This according to George Washington University anthropologist Chet Sherwood. He and his colleagues compared MRI scans of human and chimp brains.

CHET SHERWOOD (The George Washington University):

The results showed that the frontal lobe and hippocampus reduced in size over the lifespan in aging whereas that kind of shrinkage or volume loss does not occur in chimpanzees over their lifespan.


He says these brain areas are important for the cognitive functions and memory formation required by our long and complex lives. So shrinkage may be the inevitable result of oxidative damage to these structures over long lifetimes. He says further studies should investigate whether the brains of other large-brained and long-lived animals like elephants and whales suffer similar shrinkage. I’m Bob Hirshon, for AAAS, the science society.