experienced goosebumps at some point in your life. But have you ever wondered why

this strange change takes over your body? Named after the way poultry looks

when plucked, goosebumps are a fairly useless trait in humans which have been passed

on by our ancestors. Each hair actually has a tiny muscle attached to it called

the erector-pili muscles and when these muscles contract the hair stands up on

end. This contraction creates a shallow depression around the hair causing the

surrounding area to protrude. And it's the stress hormone adrenaline which

triggers this physiological change to occur. So what triggers adrenaline? For

one being cold, in animals with much more hair on their body this response helps

them to stay warm. The standing hair is able to trap more air and thermal

regulate it ultimately providing an insulated barrier. Apart from this

adrenaline is also triggered under stressful situations leading to the

"fight or flight" response, like when you're scared. Cats are a perfect example,

if you give them a spook their hair shoots up on end.

This involuntary evolutionary response allows animals to appear bigger and

more intimidating. But why music has the ability to cause chills or "frisson" as

it's called is not fully understood. One interesting theory suggests that

elements of music such as sudden volume changes or unexpected unique sections

induce a sub-conscious fear response. The body loves predictability and so

anything surprising to the autonomic system stimulates an alarm. But this fear

quickly subsides as our brain realizes, "hey, it's just music". And this contrast in

experience causes the frisson and your goosebumps. There are other

theories as well, ultimately the brain is extremely complex and so a relationship

between music, emotion and physiological responses is difficult to decipher but

in science it's okay to say that we don't know...yet.

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