Why don’t people get Goosebumps on their faces?
It’s one of the few things that separate you from chimpanzees. We get Goosebumps only on parts of our bodies that have hair.
Goose bumps are caused by small muscles in the skin called erector pilae. Each of these muscles is attached to a hair follicle. So, when the muscle contract, the hair stands up straight. In many animals this provides extra insulation by trapping air between the hairs, or makes them look slightly larger by causing all its hairs to stand out, which can be useful when the animal is threatened and wants to make itself look as big and mean as possible. Example, a threatened cat. In humans the same phenomenon is going on, except that our hair is not thick enough to make a real difference for insulation or for threats. Still, we get goose bumps when we are cold or frightened.
In the face, we still have erector pilae like muscles, except that they have grown much larger. These muscles are known as the muscles of facial expression. In most animals, their main job it to aid in chewing and keeping the mouth closed. They still serve these functions in humans, but they also allow us to smile, frown and make a number of other faces to convey emotion.
So, we don’t get goose bumps on our face because the skin muscles have other more important functions in that area.