Arousal by itself, Grahn tells me, is emotionally neutral – excitement and fear result in much the same set of physiological changes. Only by asking a subject if they’re elated or afraid can we tell the difference. Musical chills are usually experienced as pleasurable, even ecstatic. If it’s the mind that provides the emotional colouring in, what’s going on in there?
Researchers have shown that activity in the nucleus accumbens, deep inside the brain, increases during chills. “What’s interesting about this,” says Grahn, “is that it’s what we call a reward structure. So it responds to all sorts of biological rewards like food, or sex or drugs. And the chemical that’s released during musical chills, dopamine, is one that is also acted on by things like cocaine or amphetamine or other intensely pleasurable experiences.”
Anyone who’s felt musical chills will instinctively recognise this. Not everybody does – one experiment found that 47% of non-musicians had never experienced them, which, in my opinion, is a huge misfortune for the people concerned. They are among the most instantaneously exciting sensations you can experience. They involve the body and the mind together, and often seem deeply significant: giving you access to something bigger than yourself, something ineffable.