Published Nov 08, 2019The intersection of music and science has shown us what songs we deem catchy, but a new study has delved into why listeners find pop classics from the likes of the Beatles, Genesis, Van Halen and UB40 so irresistible.
Published by journal Current Biology yesterday (November 7), the study saw a group of researchers analyze 80,000 chord progressions in 745 classic U.S. Billboard pop songs from 1958 through 1991.
Songs featured in the study included the Beatles' "Ob-La-Di, Ob-La-Da," UB40's "Red Red Wine," the Jackson 5's "I Want You Back," the La's' "There She Goes" and Van Halen's "When It's Love."
The research team — led by Vincent Cheung of Germany's Max Planck Institute for Human Cognitive and Brain Sciences — used a machine learning model to mathematically quantify the levels of uncertainty and surprise in the chord progressions.
After stripping the songs of elements including lyrics and melody, researchers played a small selection of the chord progressions to 80 test subjects, using functional magnetic resonance imaging (fMRI) to see how the brain would react to musical pleasure.
The tests found that when subjects were certain about what chord to expect next, they found it pleasant when they were instead surprised. Conversely, when the subjects were unsure about what would come next, they were pleased when the chords weren't surprising.
"Although composers know it intuitively, the process behind how expectancy in music elicits pleasure was still unknown," researcher Stefan Koelsch said. "One important reason was because most studies in the past only looked at the effects of surprise on pleasure but not the uncertainty of the listeners' predictions."
The brain imaging revealed that musical pleasure was reflected in the amygdala, hippocampus and auditory cortex, all of which play a role in learning, memory and processing emotions and sounds. The team also found that the nucleus accumbens, a region which was previously believed to play a role in musical pleasure, only reflected uncertainty.
The highest-rated chord progression that was played to subjects was the Beatles' "Ob-La-Di, Ob-La-Da," followed closely by Genesis's "Invisible Touch" and B.J. Thomas's "Hooked on a Feeling."
"It is fascinating that humans can derive pleasure from a piece of music just by how sounds are ordered over time," Cheung said of the findings. "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. Understanding how music activates our pleasure system in the brain could explain why listening to music might help us feel better when we are feeling blue."
Cheung added that the data collected from looking at chord progressions in isolation couldn't be used to start a hit factory, saying, "It is an important feature that could be exploited but it wouldn't be the only thing that could be used to create a pop song."
The researchers concluded, "In summary, we show...that musical pleasure depends on the dynamic interplay between prospective and retrospective states of expectation. 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.'"