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Researchers have analyzed songs from Billboard charts spanning from 1958 to 2019, and they found that the best hits have one thing in common – “harmonic surprises.” These are moments when music deviates from what we expect, adding excitement and keeping us on our toes. The study reveals that these surprises have been happening more often over time as listeners become familiar with new musical patterns.
Take Childish Gambino’s 2018 track “This Is America.” The song was a massive hit, and for a good reason. It plays with our expectations by switching between upbeat choral melodies and dark trap beats, keeping listeners engaged. The song is full of harmonic surprises, which is why it tops the list of Billboard hits with the most unexpected musical moments. According to a study in Frontiers in Human Neuroscience, harmonic surprise in music has actually been increasing over the years—a trend that the researchers call “inflationary surprise.”
Scott Miles, a neuroscientist and co-author of the study, explains: “Music is culture. Culture evolves over time, so the content of music needs to evolve as time goes by just to have the same success as previously released music.”
This idea reflects how music adapts to changes in culture and how it also affects the brain. The researchers at Secret Chord Laboratories (SCL), where Miles works, have been studying how music impacts the brain for years. This study combines their previous research from 2017 with data from Billboard hits between 2000 and 2019, showing how harmonic surprise has become a crucial ingredient in creating a hit song.
The study also finds that music with these surprises triggers our brain’s reward system and releases dopamine. Our brains get hooked on familiar patterns but crave novelty to stay engaged. Think of how our expectations for what excites us evolve. People who were teens in the 2000s had different expectations from those in the 2010s, meaning music needed to be more surprising to keep listeners interested.
“It all comes down to how we orchestrate learning and how we’ve evolved to develop culture,” says Miles. “Our statistical expectations of harmonic regularities are not hard-coded. These statistical learning centers are very close to the emotional bonding centers of our brains. It’s not only dopamine, it’s also serotonin and oxytocin [involved]. So as technology has advanced, nurture and nature have become a lot more blurred.”
The study highlights that harmonic surprises are important in making great music. For example, “This Is America” shifts from a D minor/B flat major chord progression to a completely different key at one point, surprising listeners and keeping them interested. Another example is Nirvana’s Smells Like Teen Spirit, where dynamic shifts create a sense of surprise, despite the lack of harmonic complexity in other hits.
“Nobody listens to just a collection of chords, they listen to the whole song,” said Miles. “When we look at other features, we’ve found some evidence that surprise in a particular feature will get saturated, and it will migrate [to a different feature].” This explains how the complexity of surprise in music evolves. As listeners become accustomed to harmonic surprises, musicians shift to other elements like rhythm, tempo, or dynamics to maintain the surprise.
However, could this trend of increasing surprise go too far? That’s something the researchers are still exploring. Music isn’t just about chords; there are other elements like rhythm and dynamics that can also surprise listeners. As music continues to evolve, it’s possible that surprises will shift from harmonic changes to other musical aspects.
The study sheds light on how our expectations in music work. We need enough surprise to keep us interested, but too much can take away the enjoyment. It’s all about finding the right balance. What’s clear is that music, like culture, is constantly evolving, and as listeners, we evolve alongside it.
As fascinating as harmonic surprises are, it’s also worth noting that other musical elements, like Pythagorean tuning, can influence how music is structured. Similar to life, where too much familiarity can be boring and too much novelty can feel uncomfortable, music thrives on balance. It’s a perfect mix of the expected and unexpected that keeps it fresh.
“Music is culture. Culture evolves over time, so the content of music needs to evolve as time goes by just to have the same success as previously released music,” said co-author Scott Miles. “This study gets to the heart of what is a dynamic effect within popular culture in a very concrete and measurable way. These findings [also] help further our understanding of how music is processed in the brain.”
Study - Journal Frontiers in Human Neuroscience
2017 Study - A Statistical Analysis of the Relationship between Harmonic Surprise and Preference in Popular Music
Image Credits - Unsplash
