A bad day can be made better with the right jam, and a boring commute is that much more enjoyable with your favorite tune in the background. But why does music have such a powerful impact on us? And why do we like it so much?

We know that music has a special significance to humanity, as it’s popped up (either independently or through a cultural exchange) in virtually every society in history. We experience that special significance daily when we put our headphones on or relax after work with a nice record.

Back in 2001, researchers at the McGill University in Montreal used magnetic resonance imaging (MRI) to show that people listening to music showed activity in the limbic and paralimbic brain areas, which are related to the reward system. This reward system doles out dopamine, which makes us feel pleasure, as a reward for sex, good food, and so on. Addictive drugs also work by coaxing the production and release of dopamine in the brain.

That being said…

We don’t really know why, to be honest

But we do have a number of theories.

Back in his 1956 book Style and Music: Theory, History, and Ideology, philosopher and composer Leonard Meyer proposed that the emotional response we get from music is related to our expectations. He built on previous theories (the belief-desire–intention model) that the formation of emotion is dependent on our desires. The inability to satisfy some desire would create feelings of frustration or anger but, if we do get what we want, we get nice feelings as a reward. Delayed gratification also makes an appearance here: the greater the split between frustration and when we actually get what we want, the better we will feel once we get it, the theory goes.

In Meyer’s view, because music works with patterns, the human brain subconsciously tries to predict what the next note or groups of notes will be. If it’s right, it gives itself a shot of dopamine as a reward. If it’s not, it will try harder, and get a higher shot of dopamine once it eventually succeeds. In other words, simply having an expectation of how the song should go makes it elicit emotions in our brain, regardless of whether that expectation proves to be right or not.

It’s a nice theory, but it’s very hard to test. The main issue with it is that music can be so diverse that there are virtually endless ways to create and/or go against expectations, so it’s not exactly clear what we should test for. A song can rise or fall quickly, and we may expect a rising song to continue to rise — but it can’t do that indefinitely. We know jarring dissonances are unpleasant, but there also seems to be a cultural factor in play here: what was top of the charts two thousand years ago may sound completely horrendous today. You can listen so some reconstructions of ancient music here and here.

Expectations are in large part driven by how a particular piece we’re listening to has evolved so far, how it compares to similar songs, and how it fits in with all the music we’ve listened to so far. We all have our own subconscious understanding of what music ‘should be’ and it is to a large degree driven by our culture. This is why jazz, a melting pot of musical genres and methods, first sounds a bit off to those unacquainted with it.

Music also seems to have a physiological effect on humans. Past research has shown that our heartbeats and breathing patterns will accelerate to match the beat of a fast-paced track “independent of individual preference”, i.e. regardless of whether we ‘like’ the song. It’s possible that our brains interpret this arousal as excitement through a process called brainwave entertainment.

One other possibility is that music activates the regions of the brain that govern and process speech. As we’re very vocal and very social beasts, we’re used to conveying emotion via speech. In this view, music acts as a specific type of speech and as such can be a vehicle for transmitting emotion. Because we have the tendency to mirror the emotions of others, the song would end up making us ‘feel something’.

Music is a very rich playground — it may very well prove to be infinite. Our enjoyment of it also hinges on a very large number of very subjective factors, further complicating attempts to quantify the experience.

From a scientific point of view, it’s very interesting to ask why music sends chills down our spine. From a personal point of view, however, I’m just very thankful that it can.