Why some songs make our heart swell and others give us butterflies

Scientists have found patterns of music that make our heart beat faster or cause us to feel like our stomach is doing somersaults.

When the sequences of chords – three or more musical notes played at the same time – take a different turn from what we are expecting, it seems to trigger a strong sensation around the heart, whereas those that follow an easy-to-anticipate pattern feel like they hit us in the gut.

“Music has this unique power to stir emotions that are beyond words,” says Tatsuya Daikoku at the University of Tokyo in Japan. “It’s not just an auditory experience, it’s physical. When music plays, sometimes our body shivers or we feel a warmth around our heart – emotions that are hard to articulate.”

Researchers have already shown that music can evoke strong emotional reactions, but Daikoku – a pianist and composer – and his colleagues wanted to know where people feel those emotions in their bodies. To uncover this, they first used analytical and statistical software to break down 890 songs from the US Billboard Hot 100 chart.

The software judged the songs’ chord-to-chord sequences as being different variations of high or low levels of both surprise and uncertainty. For example, some sequences consisted of a low surprise, low uncertainty chord followed by another low surprise, low uncertainty chord, while others were a low surprise, low uncertainty chord followed by a low uncertainty but high surprise chord.

From this, the researchers created 92 musical segments of four-chord sequences, each representing one of the eight possible different surprise and uncertainty combinations. They then asked 527 volunteers to listen to different sets of all eight of these chord patterns, while looking at an online silhouette of the human body.

The listeners were instructed to click on the places on the body where they felt a physical reaction within 10 seconds of hearing the music. Afterwards, they completed an online survey about the emotions they felt when hearing the chords.

The researchers found that, when the first three chords followed an easily predictable pattern, the main differences in bodily sensations had a lot to do with what happened at the fourth chord. If that fourth chord followed the expected pattern, people felt it in their abdomen, but if it deviated from the expected pattern, they felt it around their heart.

With regard to emotions, the participants reported greater feelings of calmness, relief, satisfaction, nostalgia and empathy when chord progressions followed a predictable pattern. When the first three chords were predictable and the fourth was unsurprising, even if it was relatively difficult to predict, they generally felt reduced feelings of awkwardness or anxiety, compared with the other chord arrangements.

The findings “shed light on how music doesn’t just touch our ears, but also our bodies and hearts”, says Daikoku. “Music has the power to elicit these strong embodied emotions, guiding us to understand our inner emotional landscape in ways that words cannot.” Such understanding could one day lead to better mental health interventions, he says.