The Biology Behind Goose Bumps

Goose bumps, properly known as the pilomotor reflex, is essentially a temporary change in the skin. The reason goose bumps are called “goose bumps” is because of the little bumps produced on the surface of the skin. This resembles the elevated skin of poultry after the bird’s feathers have been plucked, thus receiving names goose bumps, turkey bumps, or duck bumps. Today, goose bumps are caused by two main things.

So why do we get goose bumps when we become chilled, or have strong emotions such as fear, pleasure, or other causes of arousal? The answer goes back to before humans were completely evolved. We inherited this phenomenon from our ancestors, which was more useful for them than it is for us today. Back in the day, when homo sapiens were a little hairier than they are today. When our ancestors would become cold, goose bumps would cause their hairs to stand up, helping them stay warm. When they became frightened or were confronted by an enemy or predator, goose bumps would create an increase our ancestors surface area. This caused them to appear bigger, making them more intimidating. So in general, goose bumps served two main purposes, to stay warm and as a defensive technique to fend off foes.

One of the main causes of goose bumps is cold temperatures. When the skin is effected by the cold, it causes our pores to contract. The cold surroundings cause the tiny muscles attached to each hair follicle to contract. The contraction causes the hairs to stand up, while at the same time, it causes a “bunching” of the skin surrounding the hairs. This is what makes the bumps we see. The standing up of the hairs helps the body preserve its own heat, helping the reduction of heat loss.

When people say they feel like their hair is “standing on end” it is because of goose bumps. Goose bumps, in terms of intense emotion are due to a reflex caused by the flight-or-fight response. This response was named based on our primitive response to fight or flee in the presence of harm or stressful stimuli. The flight-or-flight response causes the sympathetic nervous system of the body to release adrenaline into the blood stream. Adrenaline (epinephrine), is a hormone secreted by the adrenal glands. It increases the rate of metabolism, heart rate, breathing, and sometimes body temperature. This adrenaline causes a widening of blood vessels in the skin. This then causes the contraction of pili muscles at the base of hair follicles, causing them to become erect and stand up.

In summary, while goose bumps do not really serve a huge purpose for modern humans as they did for our less evolved brethren, the history and biology behind these little protrusions is helpful in understanding our ancestors. Goose bumps also occur in other mammals as well. A good example of this transpires in porcupines. Porcupines will raise their quills when they feel threatened by a predator, making them seem bigger and more intimidating. Another example is in cats. When they feel frightened, the hairs on their back stand up; this is all caused by goose bumps.

Works Cited

  • Bubenik, George A. “Why Do Humans Get “goosebumps” When They Are Cold, or under Other Circumstances?” Scientific American Global RSS. ScientificAmerican, 1 Sept. 2003. Web. 26 Nov. 2015.
  • Darwin, Charles. The Expression of the Emotions in Man and Animals. Chicago: U of Chicago, 1965. Print.
  • “Goose Bumps.” Wikipedia. Wikimedia Foundation, n.d. Web. 26 Nov. 2015.
  • Kumaar, Naveen. “What Is the Biological Happening in Our Body at the Time of Goosebumps?” – Quora. N.p., n.d. Web. 26 Nov. 2015.
  • Lynch, Brittany A. “What Are Goosebumps?” – Science in Our World: Certainty & Controversy. N.p., 12 Oct. 2011. Web. 26 Nov. 2015.
  • Myers, David G. Psychology. Ninth ed. New York: Worth, 2010. Print.

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Biology Teacher

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