Researchers have discovered a simple and measurable explanation for why certain pop songs become big hits: It primarily comes down to the song having an element of surprise with a return to normality. The study, published in the journal Frontiers in Human Neuroscience, linked the harmonic structure of pop songs to their placement in the charts.
“The most popular songs tend to include relatively rare chords, that is, they typically have high harmonic surprise,” says Norberto Grzywacz, a Professor of Neuroscience and Physics, who conducted this research at Georgetown University. “These songs also tend to have choruses with relatively low harmonic surprise preceded by sections with many rare chords.”
Harmonic surprise can be defined as the point in which the music deviates from the listener’s expectations. Scientists have hypothesized that these changes in harmony may trigger a pleasurable reward response in the brain. In fact, harmonic surprise can increase the likelihood a song will be a hit.
“When listening to music, we enjoy some pieces and dislike others. Multiple reasons govern how much we like a piece of music, including compositional, emotional, and cultural. We evaluated the role of a compositional element — the harmonic surprise,” said Grzywacz.
“Surprise is important because it is a measure of new information; something that the reward centers of the brain recognise as being of value, leading to a positive emotional response. Therefore, our finding that the most popular songs tend to include surprising chords reflects our brains in-built preference.”
It is not just the surprise element of a song that the brain deems as pleasurable, but the return to normality too.
“The brain enjoys surprise only up to a point, because unexpected events indicate a failure of prediction,” said Grzywacz. “Hence, the release of tension from surprising sections of a song to common choruses is also signalled positively by the reward centers. Our research reveals that the brain has a deep-rooted preference, which can affect whether people enjoy a piece of music.”
For the study, the researchers analyzed chord-by-chord transcriptions of the harmonies of 545 songs that entered the American Billboard Hot 100 charts between 1958 and 1991.
Grzywacz and his colleagues measured how far the chords of the song deviated from what was expected. For example, in Western tonal music, C major is often followed by G and F major; a change from this would be regarded as a surprise. These measures of surprise were compared throughout the entire song and between song sections.
“We then used the peak position of the song in the weekly Billboard Hot 100 chart to determine its popularity,” said Grzywacz.
Their findings revealed that verses, not the choruses or bridges, accounted for much of the difference in harmonic surprise between the most and least popular songs in the Billboard Hot 100 chart.
The researchers suggest that high surprises in the harmony of a song, as well as high surprises followed by a lower-surprise section, can both contribute to the enjoyment of an unfamiliar piece of music.
Grzywacz explained where the research is heading next. “Our group is taking this line of inquiry in many directions. We are assessing whether harmonic surprise has a historical memory; does a song released in 1980 have to be surprising relative to songs released in that year, or songs released in previous years — 1979, 1978, 1977, …or 1950…?” he said.
“We have a theory that chords from past music matter for surprise in new songs. For example, imagine that someone today composes a piece of music like Mozart. They would not be deemed a creative genius, even if the composition was excellent.”
The research team also hopes to measure the effect of harmonic surprise — for example, how big it needs to be to make a song popular.
“We’ve composed artificial music that have different levels of surprise and contrasts between high and low surprise sections. Volunteers will evaluate preference for these pieces of music, to assess how much these factors can affect their preference,” said Grzywacz.
“My colleagues and I are performing similar measurements and experiments with portrait paintings. Our overall goal is to use this knowledge to develop a general theory of how the brain experiences beauty in art.”
Source: Frontiers in Human Neuroscience