About two per cent of the world’s population simply doesn’t like music. They don’t dislike a specific genre — these people don’t like any music at all.
Hooking them up to physiological recording machines and playing them well-liked music shows their hearts do not race and their skin shows no sign of chills, even though they recognize the music as well as anyone else, and their brains are otherwise healthy. Robert Zatorre (McGill University), a senior fellow in CIFAR’s Brain, Mind & Consciousness program, was involved in the study that discovered this subsection of the population. He calls this phenomenon music anhedonia, which literally means the inability to feel pleasure from music. He is trying to understand the neuroscience behind it.
Zatorre thinks that our pleasure in music is deeply tied to our ability to make predictions about what is coming next, according to studies of the brain regions that music activates. We anticipate rhythms and enjoy surprises. According to his research, the brain releases the hormone dopamine during the most pleasurable moments in a song.
“We know the brain is very much a kind of prediction engine,” says Zatorre. We are constantly making mental predictions about what will happen around us, and this is true for music too.
Most Western music has moments of high tension, followed by resolution, and our brains follow along intently for what is coming. “If you ask music theorists they will say that emotion in music is often a consequence of this tension and resolution, or the ability to anticipate that an event is coming,” Zatorre says.
The mystery of musical anhedonia is why some individuals don’t enjoy music as others do. It is not because of a more general inability to feel pleasure. Zatorre and his colleagues have found that musical anhedonics experience normal pleasure when given the chance to win money, for example. This suggests that their brains’ reward systems are not dysfunctional. And it isn’t that they can’t perceive the music. In addition, none of them has amusia, a disorder related to the inability to process and remember music.
“They can tell you about the piece of music. ‘This one is meant to be happy, this one is meant to be sad, this one is good dance music, this one is a lullaby.’” Zatorre says. And yet none of them feel any joy or excitement when they hear these pieces.
“We were very puzzled about this,” says Zatorre, who is a classically trained organist and a tango aficionado, having grown up in Argentina. His research focuses in part on why humans enjoy music, and the discovery that some people don’t was a surprise.
Scientists still don’t know what is happening in the brains of this group of people that might keep them from responding the way others do. However, Zatorre is using brain imaging to test the hypothesis that their brains’ auditory systems might not interact properly with their reward systems.
“In a Science paper, we found that when you listen to music that you find pleasurable, not only does the reward system become active, but it also increases its cross-talk with the auditory cortex,” Zatorre says. And so it follows that a lack of enjoyment could point to a problem in this communication.
Zatorre says clinicians have expressed interest in his work as it relates to disorders of the brain’s reward system. “If you look at many of the social ills that affect the world, a lot of them are related to problems with regulating the reward system,” he says. Depression, post-traumatic stress disorder and addiction all involve dysfunction in this important system. Zatorre’s research presents some of the first evidence that someone can have a perfectly normal response to one typical reward, money, but not another, music.
The irony is that people with musical anhedonia don’t consider themselves to have a disorder. Some complain that it hurts their social life, but others aren’t troubled by it, Zatorre says.
“Some of them say don’t try to cure me because there’s nothing wrong with me — and I respect that,” he says.
Nonetheless, he is keen to uncover the biology behind apathy for an art form that some consider an essential part of their lives. Zatorre was invited to join CIFAR’s program in Brain, Mind & Consciousness because experts think art, and in particular music, plays a central role in the human experience, and may therefore be an essential component for understanding consciousness.