Blame the cold or the millionth time you’ve listened to “Shallow.” Goosebumps (or goosepimples), known in medical parlance as piloerection, are caused by contractions in small muscles that are connected to hair follicles. This creates a depression on the skin’s surface, resulting in the hairs standing upright. Its name comes from the resemblance of skin to that of a plucked bird.
It is believed that this is an inherited trait from our prehistoric ancestors. They had thicker coats of body hair, which created insulation and kept the body warm when stimulated. While our layer of body hair is too thin to make this insulation process effective, the muscle contraction and increased electrical activity does help to stimulate the body, which is why goosebumps go away when you warm up.
Goosebumps are also associated with a wide range of emotional situations. People talk about getting goosebumps when scared, or while listening to rousing songs or watching a high-stakes sporting event. Goosebumps can be triggered by the subconscious release of the testosterone hormone. When high levels of stress occur, whether positive or negative, testosterone is released to help in the fight-or-flight decision-making process. This cues goosebumps, and we start to feel our hair prick up.
Goosebumps may be a little mysterious, but generally speaking, when you feel them cropping up, all you need to do is take a deep breath, relax a little, and maybe put on a sweater.