Why Do We Get Goose Bumps?
Channel: Science Saturdays
Date: 2014-01-04

Learn more for free: https://www.khanacademy.org/a/372h

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Cutis anserina, commonly known as goose bumps, have no purpose. Or at least that's how it seems. So why do we get goose bumps? Goose bumps are a vestigial reflex, meaning that they have lost their ancestral function in our species. However, back when we were primates, goose bumps purposely occurred for two reasons, being cold, and having extreme emotions, some of which include fear, nostalgia, pleasure, sexual arousal, awe, admiration, and euphoria. So why do we get goose bumps in what seems like two totally separate cases? Well just as goose bumps have two causes, they also have two purposes. When the body is cold, the arrector pili muscles located at the base of each hair follicle contract, making the hair erect. In response to this involuntary reflex, the skin bunches up, creating what we know as a goose bump. In return, an extra layer of insulation is created, maintaining the body's temperature. Since humans don't have a lot of hair nowadays, this once essential reflex now serves us no purpose. On the other hand, when we experience a strong, stressful emotion like fear, our sympathetic nervous system pumps adrenaline through our body, once again starting the goose bump reaction, formally known as the piloerection reflex. Although the same reflex is occurring, it now occurs for a different reason. When the hair stands erect, the human now appears bigger, a trait that was very helpful in intimidating predators back in time. Today goose bumps are more of a nuisance than they are a help, but ultimately we still have them because humans just simply haven't gotten rid of them through evolution.