Book 1, Question 1
Why Do We Get Goosebumps? Tiny Muscles, Big Bumps!
Ever felt your skin turn bumpy when you were cold or hearing a spooky story? Tiny muscles at the base of each hair, called arrector pili, pull the hair upright and push the skin up into a bump. Scientists call this piloerection, and it may be a leftover trick from our furry ancestors, whose standing-up fur trapped warm air. Cats, dogs and chimps get goosebumps too, and strong feelings or moving music can trigger them in seconds.
From the book
Page from A Million Whys Book 1
More fun facts
- Doctors have extra names for them. Cutis anserine means goose skin. Horripilation and the pilomotor reflex are two more.
- They can show up anywhere you have hair, including your neck, your arms, and your legs.
- You do not choose them. Nerves from the sympathetic nervous system, the fight-or-flight system, tell the tiny skin muscles to tighten.
- A threatened porcupine can puff out its quills in this same kind of reflex. The raised quills make it look bigger and more dangerous.
- In 2020, a Harvard team studied mice and found that the goosebump muscle helps a nerve reach the stem cells that grow hair. When the mice stayed cold, that nerve released a chemical called norepinephrine, and new hairs started growing in less than two weeks. That finding is from mice. It is not a hair treatment for people.
- A wave of chills from music, a movie, or a powerful speech has its own name: frisson.
- Most people cannot make goosebumps happen just by deciding to. A few people can. In one study, the bumps often started at the back of the head or the neck. Those tiny muscles are not wired for ordinary conscious control, so scientists are still figuring out how those people do it.
Sources: Cleveland Clinic, Harvard Health Publishing, National Institutes of Health, Harvard Stem Cell and Regenerative Biology, Northeastern University
Questions kids ask
Can you make goosebumps happen on purpose?
Most people cannot. A few people can start them on purpose, often from the back of the head or the neck.
Are goosebumps something to worry about?
Usually no. They are a normal reaction to cold or a strong feeling. If they keep happening for no clear reason, a grown-up can ask a doctor.