From a cool breeze tickling your neck to a sense of impending danger, we have all experienced something called goosebumps at some point. You might also experience goosebumps when you hear an inspirational speech or song,. But it’s not because the tune is beautiful, or the words are just right. Goosebumps simply has to do with a tiny muscle that surrounds the root of every hair on your body. When the muscle tightens, a small bump appears on your skin.
The scientific term for goosebumps is piloerection. It’s a reflex that causes tiny muscles near our hair follicles to contract and raise the hairs. Interestingly, Goosebumps are in fact an evolutionary holdover from when we were cavemen and women and were much hairier then we are today. A cool would cause the hair to rise and then fall back, where it will trap warm air close to the skin and help warm the body back up. Obviously, humans no longer need this reaction as our clothing and weapons satisfy these needs, and we really don’t have all that much hair anymore to make this physiological response useful… well, most of us, anyway; as such, at least for these purposes, goosebumps are considered a vestigial trait.
Another cause of piloerection is the sympathetic nervous system. This is a series of autonomous reflexes that are activated when danger is sensed and manages a bunch of physical reactions to get ready for action. In addition to quickening the heart rate and activating the sweat glands, the body raises our hair in order to look bigger and tougher to a potential threat, much like a cat who’s about to fight. This is also a holdover from an earlier stage in our evolution. Goosebumps can simply be a function of the autonomic nervous system reacting to a primal threat.