Goose bumps, goose pimples, chicken skin. Whatever you call it, you've probably experienced the prickling phenomenon that makes your arm hair stand up straight. If you've ever wondered why this happens, the science is pretty simple.
As NPR explains in the video above, it's adrenaline at work. Adrenaline stimulates small muscles to pull on the hairs' roots. Charles Darwin theorized that goose bumps were a physiological defense: Since our ancestors were hairy, goosebumps would give them a fuller look, making them appear bigger and more intimidating to threats. This raised hair also helped keep us warm, which may be why we get goosebumps when we're cold, too.
But we also get "the chills" for reasons that don't seem to have anything to do with survival, such as listening to music or getting a head massage. Why? Watch the video to learn all about it.
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