Play it again, Sam
Second study looks at what makes a popular song popular.
By Nick Carne
Nostalgia or not, there seems to be an academic need to look at why pop music appeals.
Late last month, Canadian neuroscientists released a study suggesting that humans are attracted to songs that are familiar-sounding but a little bit unpredictable.
Now a new paper published in the journal Current Biology has found pretty much the same thing.
"Songs that we find pleasant are likely those which strike a good balance between knowing what is going to happen next and surprising us with something we did not expect,” says co-author Vincent Cheung from Germany’s Max Planck Institute for Human Cognitive and Brain Sciences.
In their study, Cheung and colleagues stripped out the easily recognisable lyrics and melody from 745 songs that made the US Billboard charts between 1958 and 1991 and just focused on the chord progressions.
They played a collection of different chord sequences to listeners then used a machine-learning model to mathematically quantify their responses.
They found that when people were relatively certain about what chord to expect next, they found it pleasant when they were instead surprised. However, it they were uncertain about what to expect, they found it pleasant when subsequent chords weren't surprising.
“In other words,” they write, “pleasantness depended on joint effects of the precision of the listener’s predictions, and the probability of the chord given the tonal harmonic context.”
That’s significant, they say, because some previous studies have suggested that musical pleasure in fact comes from positive reward prediction errors, which arise when what is heard proves to be better than expected.
“We showed that surprise, a retrospective response, alone cannot fully explain the link between expectations in music and pleasure,” they write.
“Our data demonstrate that uncertainty, a prospective state of expectation, is another crucial dimension needed to describe this relationship.”
Brain studies using functional magnetic resonance imaging (fMRI) support that view.
They showed that the experience of musical pleasure was reflected in three brain regions – the amygdala, the hippocampus and the auditory cortex – that play a role in processing emotions, learning and memory, and processing sound, respectively.
In contrast, activity in the nucleus accumbens – a brain area that processes reward expectations and had previously been believed to play a role in musical pleasure – only reflected uncertainty.
"Our fundamental ability to predict is therefore an important mechanism through which abstract sound sequences acquire affective meaning and transform into a universal cultural phenomenon that we call 'music’," the researchers write.
In other words, they suggest, music perception is construed as an active process where the brain continuously updates its generative model of the environment.
Music may elicit pleasure by encouraging the listener to continuously generate and resolve expectations as the piece unfolds in time – setting it apart from the static visual objects that are traditionally studied in empirical aesthetics.
For songwriters and record company A&R teams, that might provide a guide to how to create or release the next hit.
Cheung and colleagues say their next step is to look at how information flows across different parts of the brain over time. They want to know why and how it is that people listening to music sometimes get goose bumps.