You’re watching a suspenseful movie when suddenly the hairs on your arms stand up, your skin prickles with tiny bumps, and a shiver runs down your spine. Or maybe you’re standing outside on a chilly ...

Goosebumps arise when tiny muscles around hair follicles contract, causing the hair to stand on end. Learn what triggers them and when they may be cause for concern.

Along with sweating and ear wax, goosebumps are one of several gross adaptations humans have evolved over the years. Our skin is our largest organ, and does much more than we tend to realize on a day ...