What was the last time you noticed goosebumps on your skin? Perhaps you recalled a spine-tingling memory of the past, stumbled upon a hair-raising quote on the internet, or maybe you were just feeling a bit chilly.
Goosebumps are a universal human experience, whether triggered by pleasurable arousal from nostalgic music or sudden fear of a potential threat.
Even a single ice pack pressed against a single part of your body is enough to trigger a response across your entire skin, according to independent researcher Jonathon McPhetres, who has published several papers on piloerection.
But have you ever wondered why we get goosebumps during emotional or chilly moments? This involuntary reaction, also known as piloerection, is an evolutionary masterpiece with a surprising history.
Goosebumps Are a Survival Reflex Passed Down for Generations
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As annoying as getting bumpy skin is, goosebumps may be the reason humanity survived until today. The goosebumps we experience are arguably related to our hairy ancestors, supposedly serving a life-saving purpose.
To understand why, it helps to travel back to when our evolutionary human ancestors were covered in thick body hair.
When they felt threatened by a potential predator, they would immediately activate the fight-or-flight mode to survive. Their thick body hair would instantly flare, making them appear bigger and more intimidating and scaring away the attacker.
This ability to “puff up” also helped our ancestors survive freezing temperatures. When they got cold, the fluffed-up hair from goose bumps would trap an insulating layer of air, helping conserve heat in life-threatening conditions. Similarly, snow monkeys, covered from head to toe in hair, experience goosebumps to conserve body heat in their harsh environment.
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Charles Darwin, having observed goosebumps in zoo animals when he scared them with a stuffed snake, concluded in his 1872 book The Expression of the Emotions in Man and Animals that this involuntary response is nothing more than a leftover from our ancient ancestors.
The majority of mammals today, including our closest living relatives, are entirely covered in thick, protective fur (per the BBC). Humans, on the other hand, appear to have a very thin layer of hair compared to their hairy past.
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“We technically have hair all over our bodies, it’s just miniaturised hair follicles,” explained Tina Lasisi, a biological anthropologist at the University of Southern California who specialises in the science of hair and skin. “But it’s miniaturised to the point where it functionally doesn’t insulate us anymore.”
According to the “body-cooling” hypothesis (also called the “savannah” hypothesis), we gradually shed our fur because we no longer need to generate heat in cold weather as we did in the past. While modern humans lost much of their protective coat, we’re still left with these little raised bumps to remind us of our chilling past.
Your Brain Triggers Goosebumps for Both Emotional and Physical Reasons
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Whether you’re bracing for a bloodthirsty bear in the wild, feeling happy about sudden news, or just watching an epic movie, fear, excitement, and awe can all flip the same biological switch.
Goose pimples are your brain’s way of signaling to your body that something important is currently happening, even if it’s just your favorite character entangled in a one-on-one battle with the invincible villain (per Popular Science).
“We’re not really very good at monitoring our bodies, and we don’t notice them [goosebumps] a lot of times when they happen,” said Jonathon McPhetres, an independent researcher who published several papers on piloerection while at Durham University.
No matter how serious or “silly” the emotional stimulus is, the result is always goosebumps popping up to keep your mind and body alert.
Interestingly, goosebumps are also elicited by changes in our skin’s temperature, according to McPhetres. While these changes are not particularly significant, goosebumps triggered by cold temperature in one part of our body often occur across the whole body.
“If I put an ice pack on your thigh,” he said, “I’ve changed the temperature of your thigh, and I can see different areas of your skin and your body change temperature a little bit as a response.”
Why Your Body Gets Goosebumps: 4 Key Triggers Explained
Tiny Muscles Give Goosebumps Their Signature Look
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The mechanism by which we get goosebumps has long been a topic of study and fascination. Essentially, we experience goosebumps when microscopic muscles in the skin’s hair follicles (arrector pili muscles) pull the body’s hair upright.
Think of these as tiny levers: when they contract, your hair stands on end, and the skin around it bunches up to create that signature “bumpy” texture, according to a 2020 piece published on the National Institutes of Health.
A team of researchers led by Drs. Ya-Chieh Hsu from Harvard University and Sung-Jan Lin from National Taiwan University found a “triple threat” responsible for your goosebumps: the arrector pili muscles, sympathetic nerves, and the hair follicles themselves.
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Using mouse skin samples, the team discovered that these three components are deeply intertwined. Sympathetic nerves play a key role by releasing norepinephrine, a chemical messenger that transmits signals across nerve endings (per the Cleveland Clinic). When the researchers removed the arrector pili muscles, leaving the nerves and stem cells intact, the signal to grow new hair was never delivered, proving that the tiny muscles are the vital link between our nerves and skin regeneration.
Music and Memories Are Powerful Goosebumps Triggers, Too
Many have experienced the eerie feeling of getting “the chills” while listening to certain melodies or songs. A 2016 study by PhD student Matthew Sachs at USC found a weird link between those who feel shivers when listening to music and the structure of their brains (per Neuroscience News).
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Sachs himself was inspired to investigate the topic after his colleague, Der Sarkissian, a research assistant at USC’s Brain and Creativity Institute, described his own physical response to music firsthand.
“I sort of feel that my breathing is going with the song, my heart is beating slower, and I’m feeling just more aware of the song, both the emotions of the song and my body’s response to it,” said Der Sarkissian.
The eye-opening study revealed that those who experience goosebumps as a physical response to music have stronger fiber connections between the auditory cortex and emotional processing areas in the brain, thereby having a higher potential to feel strong emotions.
“The idea being that more fibers and increased efficiency between two regions means that you have more efficient processing between them,” he concluded.
Moreover, certain memories tied to music or even an impactful life event (like the birth of your child) can send shivers down your spine (per the University of Guelph).
This is because memories are strongly linked to emotions, which, in turn, trigger the release of adrenaline and endorphins. As a result of this sudden hormonal rush, your brain responds by giving you the so-called “emotional chills”, according to George Bubenik, a physiologist and professor of zoology at the University of Guelph.
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