Despite humans having less body hair due to evolution, the phenomenon of goosebumps still occurs when the skin feels cold. As per the National Institutes of Health (NIH), goosebumps are the result of arrector pili muscles in the skin's hair follicles pulling the hair upright.
While this response helps animals with thick fur retain warmth, it serves little purpose for humans who lack sufficient hair for insulation. Nonetheless, the ability to produce goosebumps remains in humans and other hair-deficient animals.
Causes of Goosebumps
Family medicine doctor Donald Ford, MD, told Cleveland Clinic that the occurrence of goosebumps, scientifically referred to as horripilation or piloerections, is a result of the sympathetic nervous system stimulating the contraction of small muscles known as arrector pili muscles located at the base of each hair follicle.
This contraction causes the hair to erect or stand on end. The term "goosebumps" is derived from the resemblance of the skin's appearance and texture to that of a plucked bird. Below is the list of what causes goosebumps in humans:
- Goosebumps are part of the fight-or-flight response in humans, but they have become less useful over time due to reduced body hair.
- Goosebumps served as a defense mechanism for primitive humans, making them appear larger and scaring off predators.
- Goosebumps can also be associated with sexual arousal and as a response to cold temperatures, providing insulation.
- Strong emotions, such as happiness, excitement, sadness, fear, awe, or anger, can trigger goosebumps.
- Frisson, a term for aesthetic chills, refers to the shiver or tingling sensation experienced while listening to music or engaging with inspiring content.
Role of Goosebumps in Humans
Goosebumps, which occur when the body raises its hair, serve little purpose in humans but are advantageous for long-haired mammals, birds, and reptiles. According to a 2014 paper, this reaction, known as piloerection, helps fluff up fur and feathers to create insulation against the elements.
While piloerection is not beneficial for humans, Live Science reported that it is believed to be a vestigial trait inherited from our early mammalian ancestors and passed down through primates, including humans. Examples of other vestigial traits in humans include the tailbone and the appendix.
Although goosebumps do not offer significant protection for humans, they may have an alternative function related to hair growth. Research conducted on mice in 2020 revealed that removing the nerves associated with piloerection resulted in slower activation of hair follicle stem cells and delayed hair growth.
Nerves were found to be intertwined with both the muscles responsible for piloerection and hair stem cells. This suggests that piloerection may stimulate the growth of more fur in response to cold, potentially explaining its prevalence across various mammal species.
In conclusion, the presence of goosebumps in humans serves as a reminder of our evolutionary connection to mammals, birds, and reptiles. While they may not serve a significant purpose for us, they reflect a shared heritage and the retention of ancestral traits.
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