We’ve all had goosebumps at some point, most of the time we can hazard a guess as to why they show up but sometimes we have no idea. Time to delve into the science behind goosebumps. Why do we get them? Do they serve a purpose? And what’s with that name?
When we get goosebumps, the hairs on our arms, legs or torso stand up straight. The hairs also pull a little bump of skin, the hair follicle, up with them. This gives our skin the appearance of that of a plucked bird, as is reflected in the name of the effect in many languages. In Dutch they use kippenvel which translates to chicken skin, in German they use Gänsehaut or goose skin, and in Spanish it is called piel de gallina, again chicken skin. There is just no escaping the similarity between the effect and the skin of a plucked bird.
Of course there are also more formal, medical terms for goosebumps. These include horripilation, piloerection, pilomotor reflex and cutis anserine. But even here we find references to the plucked birds, as cutis means skin and anser means goose. Each of the medical terms describes a temporary change in the skin from smooth to bumpy, most commonly developed after exposure to cold.
We can’t control when we get goosebumps and when we don’t, they are an involuntary reaction. Goosebumps are caused by tiny muscles flexing in the skin, which makes the hair follicles rise up a bit. The nerves from the sympathetic nervous system, the ones that control our fight or flight response, control these tiny skin muscles. Meaning that goosebumps are caused by your instincts.
And we’re not the only animals to deal with goosebumps either. Many animals react similarly when threatened causing their fur to puff out, which makes the animal look bigger and more dangerous. Porcupines, for example, puff out their quills and cats puff out their fur when sensing danger.
In humans goosebumps are most often associated with unpleasant situations, for instance when you’re cold or feeling afraid. But there is more to it than that as other things can also cause goosebumps. The sympathetic nervous system that causes the goosebumps, gets input from many parts of the brain, including those involved with motivation, arousal, and emotion. This is why hearing music or seeing art that is particularly moving can give you the ‘chills’, as can feelings of awe, pride and excitement.
Puffing up like other animals might not be of much help to us when we feel threatened but goosebumps do still serve a purpose in humans, though perhaps not an essential purpose. Goosebumps help us, and other animals, to conserve heat when we are exposed to the cold. Contraction of the muscles in the skin generates heat, the raised hair follicles cause skin pores to close, and hairs standing up trap a layer of air near the skin and hold onto body heat.
Recent research has also linked goosebumps to the regeneration of hair and hair follicles, which can be seen as a longer-term response to cold, at least for animals with fur. The nerves connected to the tiny muscles responsible for goosebumps also connect to hair follicle stem cells, which are responsible for hair growth. So when you get goosebumps, your hair follicle stem cells get the message to grow new hair.
It’s possible that goosebumps will gradually disappear amongst humans over the coming centuries, similarly to other remnants of evolution like the tailbone and wisdom teeth. Until then, if you want your hair to grow more quickly you can always try getting chilly, no guarantees that it will work though.