New research in Psychological Science reveals that individuals swiftly develop familiarity and preference for musical melodies, particularly when they can anticipate their endings. This process, closely linked to the brain’s auditory and reward systems, varies among individuals based on their sensitivity to musical rewards. These findings provide a potential explanation for how music evolves from a novel stimulus to a rewarding experience.
Music has a unique place in human culture – it’s a source of enjoyment across the world, yet its allure has long puzzled scientists. Unlike food or shelter, music doesn’t seem to have a direct survival benefit. So, why do we love it so much? Prior research has hinted that our pleasure in music might stem from the brain’s reward system, similar to the enjoyment we get from food or love. This latest study sought to delve deeper into this phenomenon, focusing on how we respond to music that is completely new to us.
“The question of why humans enjoy music has been posed for centuries by philosophers, physicists, historians, anthropologists, and of course musicologists as well as psychologists and neuroscientists,” said study author Psyche Loui, an associate professor of creativity and creative practice at Northeastern University and director of the Music, Imaging, and Neural Dynamics Laboratory (MIND Lab).
“Across a few different disciplinary traditions, what most theories center around is the idea of prediction – you form predictions for sound patterns that you can expect, and violations of expectations, or prediction errors, change how you feel. But it’s hard to know where those predictions came from in the first place. I am interested in this topic because as a musician myself, I wanted to see how newly composed music engages the brain, and how people develop predictions and how these predictions become rewarding.”
The research, involving a series of nine studies, was conducted with 1,185 adult participants from the United States and China. The researchers used music composed in the Bohlen-Pierce scale, an unfamiliar musical system that uses a 13-tone scale instead of the octave-based system commonly used in Western music. This choice was strategic: By using an unfamiliar musical system, the study avoided the influence of participants’ previous musical experiences and biases.
The research involved three phases. In the first phase, participants listened to melodies and rated how much they liked them and how familiar they were. In the second phase, known as the exposure phase, these melodies were played multiple times, varying in frequency from just a couple of times to as many as 16 times.
In the final phase, participants were presented with both the original melodies and altered versions with unexpected endings. This setup was designed to create a prediction error – a discrepancy between what the listeners expected to hear and what they actually heard.
The researchers found that familiarity played a crucial role in music enjoyment: the more times a melody was played, the more it was liked. This aligns with the mere-exposure effect, a psychological phenomenon where people tend to develop a preference for things merely because they are familiar with them.
However, the study went further, revealing that the pleasure from music is not just about familiarity. The prediction errors – those moments when the music deviated from what was expected – significantly impacted the listeners’ enjoyment. When the music followed the expected pattern (no prediction error), listeners generally rated it higher in terms of liking. On the other hand, when the music deviated from the expected pattern (prediction error present), it affected their liking ratings negatively.
Intriguingly, when listeners had been exposed to a melody more, the impact of these prediction errors on their liking ratings was greater. The results align with the predictive coding model in neuroscience, which posits that the brain is constantly making predictions about incoming sensory information and adjusting these predictions based on new information.
The researchers found that Chinese and American participants showed similar effects of exposure and prediction errors, suggesting that the learning processes driving familiarity and liking are relatively free of cultural influence when the musical materials are unfamiliar to both cultures.
“I think the most important finding is that we can learn to like new music, independent of what culture we come from,” Loui told PsyPost. “Many conversations about why we have music, and why we like music, quickly get into topics surrounding the nature-nurture debate, but recent work on neuroscience of music has centered around reward predictions and prediction errors. This study looks at how these reward predictions and prediction errors develop rapidly with listening.”
Another compelling aspect of the study was its examination of individual differences in music-reward sensitivity. The study included two individuals identified as having music-specific anhedonia – a specific condition where individuals do not experience pleasure from music, despite having normal auditory perception.
Individuals with musical anhedonia familiarized themselves with the melodies similarly to those without the condition. Their familiarity ratings were sensitive to both exposure and prediction error, suggesting that their ability to learn and recognize music was intact. The crucial difference emerged in the domain of liking ratings. Unlike people without anhedonia, they did not derive increased enjoyment from music as their familiarity with it grew.
These findings are significant as they demonstrate that musical anhedonia is not linked to a deficit in the cognitive processing of music. Instead, the issue seems to lie in the affective, or emotional, response to music.
“Most striking was the similarity across cultures but dissimilarity across groups of people who differ by self-identification of how much they find music to be rewarding,” Loui said.
The research also extended beyond psychological analysis. In their final study, Loui and her colleagues used functional magnetic resonance imaging (fMRI) to observe brain activity in participants as they listened to the melodies. They observed greater activation in the right Heschl’s Gyrus for melodies that did not elicit prediction errors compared to those that did. The Heschl’s Gyrus is a region in the brain located in the primary auditory cortex and plays a crucial role in processing sounds, including music.
The researchers also assessed the degree of functional connectivity between auditory processing areas (like Heschl’s Gyrus) and reward-sensitive regions of the brain (specifically, the medial prefrontal cortex). They found that this connectivity increased when participants listened to pieces that were more familiar to them, which indicates a stronger link between auditory processing and reward when listening to well-known music.
“I think it’s worth noting that this study uses multiple methods, from behavioral to cross-cultural to neuropsychological and to functional MRI,” Loui said. “The convergence of these multiple approaches really gets at the problem of how music becomes rewarding from different perspectives.”
While the study’s insights are significant, it’s important to recognize its limitations. For instance, the use of the Bohlen-Pierce scale, while useful for eliminating cultural biases, also means the results might not entirely translate to more familiar musical systems. Additionally, the study focused on instrumental melodies, and the inclusion of other musical elements like lyrics or varied instrumentation might yield different results.
Future research could explore these avenues, potentially examining how different cultures and musical traditions influence the formation of musical preferences. Additionally, further neurological studies could provide deeper insights into the brain’s role in musical enjoyment.
The study, “Generating New Musical Preferences From Multilevel Mapping of Predictions to Reward“, was authored by Nicholas Kathios, Matthew E. Sachs, Euan Zhang, Yongtian Ou, and Psyche Loui.
