▁being ▁able ▁to ▁re - bal ance ▁its ▁surface ▁temperature ▁quickly . ▁ ▁The ▁stim ulus ▁of ▁cold ▁surr ound ings ▁causes ▁the ▁tiny ▁mus cles ▁attached ▁to ▁each ▁hair ▁fol lic le ▁to ▁contract . ▁This ▁contra ction ▁causes ▁the ▁hair ▁str ands ▁to ▁stand ▁straight , ▁the ▁purpose ▁of ▁which ▁is ▁to ▁aid ▁in ▁quick er ▁dry ing ▁via ▁ev ap oration ▁of ▁water ▁cl ing ing ▁to ▁the ▁hair ▁which ▁is ▁moved ▁up ward ▁and ▁away ▁from ▁the ▁skin . ▁ ▁In ten se ▁em otion ▁ ▁People ▁often ▁say ▁they ▁feel ▁their ▁" h air ▁standing ▁on ▁end " ▁when ▁they ▁are ▁fright ened ▁or ▁in ▁a we . ▁In ▁an ▁extremely ▁stress ful ▁situation , ▁the ▁body ▁can ▁employ ▁the ▁" f ight ▁or ▁flight " ▁response . ▁As ▁the ▁body ▁prepar es ▁itself ▁for ▁either ▁fighting ▁or ▁running , ▁the ▁sympath etic ▁nerv ous ▁system ▁flo ods ▁the ▁blood ▁with ▁ad ren al ine ▁( ep ine phr ine ), ▁a ▁h orm one ▁that ▁spe eds ▁up ▁heart ▁rate , ▁met abol ism , ▁and ▁body ▁temperature ▁in ▁the ▁presence ▁of ▁extreme ▁stress . ▁ ▁Then ▁the ▁sympath etic ▁nerv ous ▁system ▁also ▁causes ▁the ▁p ilo ere ction ▁ref lex , ▁which ▁makes ▁the ▁mus cles ▁attached ▁to ▁the ▁base ▁of ▁each ▁hair ▁fol lic le ▁contract ▁and ▁force ▁the ▁hair ▁up . ▁ ▁Music ▁ ▁Canadian ▁research ers ▁have ▁suggested ▁that ▁when ▁humans ▁are ▁moved ▁by ▁music ▁their ▁bra ins ▁behave ▁as ▁if ▁react