Unravelling the puzzle of musical evolution
Are humans naturally predisposed to perceive music? Or are certain elements of music – such as melody – learned? These were some of the questions that the EU-funded PHYLOMUSIC project set out to address. “We wanted to uncover where our ability to understand music comes from, from evolution to early human development,” explains PHYLOMUSIC project fellow Roberta Bianco(opens in new window), now a faculty member at the University of Pisa(opens in new window) in Italy. “Our hypothesis was that if musical capacities are there at the outset, newborns’ brains should respond similarly to those of adults.”
Brain signal analysis and auditory neuroscience
The project, which was supported by the Marie Skłodowska-Curie Actions(opens in new window) programme, set out to expand our knowledge of how musical capacity evolves. “While there has been a lot of research focusing on rhythm across species, there has not been much on melodic capacity,” says Bianco. “Let alone melody and rhythm together. This was our focus.” To do this, the project combined electroencephalography, state-of-the-art brain signal analysis, and computational auditory neuroscience. In practice, this involved playing Bach and recording the resulting brain activity in adult humans, newborns and macaques. This non-invasive method enabled the team to compare the performance of the newborn brain to the adult brain, as well as to a non-human primate brain. “In this way, we were able to figure out if some predispositions are present at birth and if they are phylogenetically conserved,” adds project coordinator Giacomo Novembre from the Italian Institute of Technology(opens in new window).
How newborns encode rhythm
The project delivered a number of fascinating new insights. These include the fact that, while human adults track and anticipate both rhythm and melody, macaques and human newborns appear to be sensitive only to rhythm, but not melody. “Does this mean that newborns and monkeys encode rhythm in the same way?” asks Bianco. “Not necessarily. This is an aspect we are currently investigating, and more work is needed to understand potential similarities or differences.” What these findings do suggest, however, is that rhythm prediction is something shared to an extent with other primates and is present at birth. “This could be because babies in the womb are exposed to rhythms – the mother, heartbeat, walking etc., while melody tends to be filtered out,” notes Bianco. “The absence of melodic tracking in monkeys and newborns also suggests that exposure to signals of communication, such as speech and music, is critical.”
Rhythmic abilities and melodic structure
This research provides a missing piece in the long-standing puzzle of musical evolution. “Rhythm likely reflects a deep, ancient auditory function shared across primates,” says Novembre. “Melody, on the other hand, appears tied to a human neural specialisation and postnatal learning. Music may be uniquely human in complexity, but its roots are older than we are.” These findings help explain why rhythmic abilities are widespread across species, whereas melodic abilities remain an achievement of humans (as well as a handful of species with advanced vocal learning capacities, such as birds). They may also shed light on why cultural variability is greater in melodic structure than in timing, as rhythm may be constrained by fundamental biological limits. The work has opened up new research possibilities, which both Bianco and Novembre are keen to explore. “One avenue would be to follow newborns from birth until about 12 months,” adds Novembre. “This kind of longitudinal study would enable us to identify when during development we start making sense of melodic structure.”
