SIC-Things That Go Goosebump

Science in the City

Things That Go Goosebump

DEAR SCIENCE WORLD,

My friend and I were lining up to ride the roller coaster and noticed he had goosebumps all over his arm. He said it was because he was cold, but I think he was afraid to go on the ride. Which one of us is right?

Some Curious Readers Exploring Arm Matters

Dear S.C.C.R.E.A.M.

Actually, you could both be right. Goosebumps are caused by a signal from our sympathetic nervous system. This signal causes the muscle fibres connected to the hair follicies on our skin to grow tighter. The tightening makes the skin surrounding the hair follicle "pucker up" into the goosebumps shape and, along with tightening muscles, also pulls the hair inside straight up.

Goosebumps are caused by a signal from our sympathetic nervous system. This signal causes the muscle fibres connected to the hair follicles on our skin to grow tighter. The tightening makes the skin surrounding the hair follicle "pucker up" into the goosebump shape and, along with tightening muscles, also pulls the hair inside straight up.

Goosebumps are very helpful for furry mammals. When goosebumps form and all their hairs are sticking up, a creature's fur traps more air to help keep it warm. If your friend was feeling cold, the goosebump reflex could have been triggered to try keep him warmer.

Goosebumps are also helpful when creatures are in danger. An animal who is frightened 'puffs up' and appears learger and more threatening as goosebumps cause it's hairs to stand up. You may have witnessed this phenomenon if you've ever seen a cat arch its back and puff up to confront an unfriendly dog. If you friend was feeling scared, the goosebumps could also have been caused by this feeling.

The nerve signals that make goosebumps are triggered in the Limbic section of our brains, an area at the top o fthe spinal cord between the two halves of our brain. The Limbic system receives alsmost all the input from our senses (in an area called the thalamus) and creates the experience of anxiety, distress and fear (in the amygdaloid nucleus). When we see or hear something frightening, our Limbic system decides that we are in danger and triggers a variety of fight or flight responses including dry mouth, increased heart rate and goose bumps.

Unfortunatley for human beings, the goosebump reflex doesn't help much. Human hairs, particularly on the our body, are so thin and fine they are often barely visible. When our hairs stand up, we don't appear larger or feel warmer, we just get the bumpy looking gooseflesh.

But they do give us something to think about when we are waiting to ride a roller coaster.

Brian Anderson, B. Sc., scaredy-cat