The idea that musical emotion arises from little violations and manipulations of our expectations seems the most promising candidate theory, but it is very hard to test. One reason for this is that music simply offers so much opportunity for creating and violating expectations that it’s not clear what we should measure and compare. We expect rising melodies to continue to rise – but perhaps not indefinitely, as they never do. We expect pleasing harmonies rather than jarring dissonance – but what sounds pleasing today may have seemed dissonant two hundred years ago. We expect rhythms to be regular, but are surprised if the jumpy syncopation of rock’n’roll suddenly switches to four-square oompah time. Expectation is a complicated, ever-changing interplay of how the piece we’re hearing has gone so far, how it compares with similar pieces and styles, and how it compares with all we’ve ever heard.
So, one corollary of Meyer’s theory is that emotion in music will be primarily culturally specific. In order to have any expectations about where the music will go in the first place, you need to know the rules – to appreciate what is normal. This varies from one culture to another. Western Europeans think simple rhythms like waltz time are “natural”, but Eastern Europeans dance happily to metres that sound extraordinarily complicated to others. All of us develop a strong, subconscious sense of which notes sound “right”, whether in sequence in a melody, or sounding together in harmonies. But because different cultures use different scales and tunings – the scales of India and Indonesia, for example, don’t respect the tunings of a piano – there is nothing universal about these expectations. A jolly piece of Indonesian music may be interpreted as “sad” by Westerners simply because it sounds close to being in the traditionally “sad” minor scale.
This picture also implies that music isn’t just about good vibrations – it can provoke other feelings too, such as anxiety, boredom and even anger. Composers and performers walk a delicate tightrope, needing to tweak expectations to just the right degree. Not enough, and the music is dully predictable, as nursery tunes seem to adults. Too much, and we can’t develop any expectations at all – which is why many people struggle with modernist atonal music.
All this can rationalise a great deal about why we feel emotions from particular musical phrases and performances. Meyer’s ideas have received further support very recently from a brain-scanning study by Zatorre and colleagues, which showed that the rewards stimulated by music heard for the first time are particularly dependent on communication between “emotion” and “logic” circuits in the brain.
But it’s not the whole story. Our emotional response to music may be conditioned by so many other factors too – if we are hearing it alone or in a crowd, for example, or if we associate a particular piece with a past experience, good or bad (dubbed the “Darling they’re playing our tune” theory).
Underneath all these ideas is the fact that we’re not even sure what kind of emotion we’re talking about. We can recognise sad music without feeling sad. And even if we do feel sad, it’s not like the sadness of bereavement – it can be enjoyable even if it provokes tears. Some music, like some of Bach’s, can create intense emotion even though we can’t quite put into words what the emotion is. So we’ll surely never understand why music stimulates emotions at least until we have a better picture of what our emotional world is really like.