Why is some music able to make us cry?

— Radhika S., Mumbai

A good song can make us cry because listening to it simultaneously invokes parts of the brain involved in emotion, memories, expectations, and arousal.

Expectation is particularly notable. As we listen, the brain constantly predicts what will come next, from a melody resolving itself to a voice reaching a particular high note. When the song suddenly fulfils or violates these expectations, the resulting build-up and release of tension can trigger strong physiological reactions, including changes in heart rate and tears.

We also associate music with autobiographical memories. When we repeatedly hear a specific sequence of rhythm, timing, lyrics, etc. the brain stores it alongside whatever else it is encoding then. When you hear the opening notes later, it can trigger the brain to recognise the old sensory pattern and ‘activate’ the larger network of information stored with it.

Sadness can also produce changes grounded in shared physiology, such as softer speech and falling pitch contours, and in cultural conventions like the association of particular harmonies with melancholy.

When other people observe these cues alongside sadness, their brains learn the association. In this way, people can be brought to cry to unfamiliar music, too.

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