Summary: Music can induce a range of emotions and help us better understand different cultures. But what makes us listen to certain songs more than others? Researchers say that when we listen to a song, our brain predicts what will happen next, and that prediction dictates whether we like that song or not.
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A few years ago, Spotify published an interactive map of musical tastes online, sorted by city. At the time, Jeanne Added was dominating in Paris and Nantes, and London had a soft spot for local hip hop duo Krept and Kronan. It is well established that musical tastes vary over time, across regions and even across social groups.
However, most brains are born alike, so what’s going on inside them that we end up with such disparate musical tastes?
Emotions – a story of prediction
If someone presented you with an unfamiliar melody and suddenly stopped it, you might be able to sing whatever note you think is best. At least professional musicians could! In a study published in the Journal of Neuroscience in September 2021, we show that similar predictive mechanisms occur in the brain every time we listen to music, without our necessarily being aware of it.
These predictions are generated in the auditory cortex and merged with the note actually heard, resulting in “prediction error.” We used this prediction error as a sort of neural score to measure the brain’s ability to predict the next note in a melody.
In 1956, American composer and musicologist Leonard Meyer hypothesized that emotion could be induced in music by a sense of satisfaction or frustration arising from listener expectations. Since then, academic advances have made it possible to identify a link between musical expectations and other more complex feelings.
For example, participants in one study were able to memorize tone sequences much better if they could first accurately predict the notes within them.
Now the basic emotions (e.g. joy, sadness or annoyance) can be broken down into two basic dimensions, valence and psychological activation, which measure an emotion’s degree of positivity (eg, sadness versus joy) and arousal (boredom versus anger), respectively. The combination of the two helps us define these basic emotions.
Two studies from 2013 and 2018 showed that when participants were asked to rank these two dimensions on a sliding scale, there was a clear relationship between prediction error and emotion. For example, in these studies, musical notes that were less accurately predicted led to emotions with greater psychological arousal.
Throughout the history of cognitive neuroscience, pleasure has often been linked to the reward system, especially with regard to learning processes. Studies have shown that there are particular dopaminergic neurons that respond to prediction error.
Among other functions, this process allows us to learn and predict the world around us. It is not yet clear whether pleasure motivates learning or vice versa, but the two processes are undoubtedly linked. This also applies to music.
When we listen to music, the greatest pleasure comes from events predicted with a moderate level of accuracy. In other words, events that are too simple and predictable – or even too complex – do not necessarily induce new learning and therefore only generate a small amount of pleasure.
Most of the fun comes from events that fall in between – those that are complex enough to spark interest but consistent enough with our predictions to form a pattern.
Predictions dependent on our culture
Nevertheless, our prediction of musical events remains inexorably linked to our musical education. To explore this phenomenon, a group of researchers met with the Sami people, who inhabit the region that stretches between the far north of Sweden and the Kola Peninsula in Russia. Their traditional song, known as yoikdiffers greatly from Western tonal music due to limited exposure to Western culture.
For a study published in 2000, musicians from the Sami regions, Finland and the rest of Europe (the latter coming from various countries unfamiliar with yoik singing) were invited to listen to excerpts from yoiks that they did not had never heard before. They were then asked to sing the next note of the song, which had been intentionally omitted.
Interestingly, the distribution of data varied considerably between the groups; not all participants gave the same answer, but some ratings were more common than others within each group.
Those who most accurately predicted the next note of the song were Sami musicians, followed by Finnish musicians, who had more exposure to Sami music than those from elsewhere in Europe.
Learning about new cultures through passive exposure
This brings us to the question of how we learn about cultures, a process known as inculturation. For example, musical time can be divided in different ways. Western musical traditions typically use four-beat signatures (as often heard in classic rock ‘n’ roll) or three-beat signatures (as heard in waltzes).
However, other cultures use what Western music theory calls a asymmetrical meter. Balkan music, for example, is known for asymmetrical meters like nine- or seven-beat signatures.
To explore these differences, a 2005 study examined folk melodies with symmetrical or asymmetrical meters.
In each, beats were added or removed at a specific time – known as an “accident” – and then participants of different ages listened to them. Whether the room had balanced or unbalanced meter, infants six months or younger listened for the same amount of time.
However, 12-month-olds spent significantly more time staring at the screen when “accidents” were introduced in symmetric counters compared to asymmetrical counters.
We could deduce that the subjects were more surprised by an accident in a symmetrical meter because they interpreted it as a disturbance of a familiar pattern.
To test this hypothesis, the researchers had the infants play a CD of Balkan music (with asymmetrical measurements) at home. The experiment was repeated after a week of listening, and infants spent equal time staring at the screen during the introduction of crashes, whether the meter was symmetrical or asymmetrical.
This means that by passively listening to Balkan music, they were able to construct an internal representation of musical meter, which allowed them to predict pattern and detect crashes in both types of meters.
A 2010 study found a surprisingly similar effect in adults – in this case, not for rhythm but for pitch. These experiments show that passive exposure to music can help us learn the specific musical patterns of a given culture – formally known as the process of inculturation.
Throughout this article, we’ve seen how passive listening to music can change the way we predict musical patterns when presented with a new piece. We also looked at the myriad ways listeners predict such patterns, depending on their culture, and how it distorts perception by making them experience pleasure and emotions differently. Although more research is needed, these studies have opened up new avenues for understanding why there is such diversity in our musical tastes.
What we do know so far is that our musical culture (i.e. the music we have listened to throughout our lives) distorts our perception and causes our preference for certain tracks over others, whether by similarity or by contrast with pieces that we have already heard.
About this music and neuroscience research news
Source: The conversation
Contact: Guilhem Marion – The Conversation
Image: Image is in public domain
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