Musical surprises light up the brain’s reward center

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Surprises in music activate the reward center of our brains, and help us learn about the music as we listen, research finds.

Researchers put 20 volunteers through a musical reward learning task. Each participant chose a color, then a direction. Each choice came with a certain probability of leading to either a consonant, pleasurable musical excerpt or a dissonant, unpleasant one.

Over time, the subjects learned which choices were more likely to produce both consonant and dissonant music. The researchers designed the test to create an expectation of either musical enjoyment or dissatisfaction. Subjects performed this task while researchers measured their brain activity with functional magnetic resonance imaging.

Using an algorithm, the researchers then determined the reward prediction error for each choice—the difference between an expected reward and the actual reward received. They compared that data to the MRI data, and found that reward prediction errors correlated with activity in the nucleus accumbens, a brain region that in previous studies has been shown to activate when the subject is experiencing musical pleasure.

This is the first evidence that musically elicited reward prediction errors cause musical pleasure. It is also the first time an aesthetic reward such as music has been shown to create such a response. Previous studies have focused on more tangible rewards such as food or money.

Subjects whose reward prediction errors most closely matched activity in the nucleus accumbens also showed the most progress in learning the choices that led to the consonant tones. This establishes music as a neurobiological reward capable of motivating learning, showing how an abstract stimulus can engage the brain’s reward system to potentially pleasurable effect and motivate us to listen again and again.

“This study adds to our understanding of how abstract stimuli like music activate the pleasure centers of our brains,” says Ben Gold, a PhD candidate in the lab of Robert Zatorre at the Montreal Neurological Institute and Hospital of McGill University.

“Our results demonstrate that musical events can elicit formally-modeled reward prediction errors like those observed for concrete rewards such as food or money, and that these signals support learning. This implies that predictive processing might play a much wider role in reward and pleasure than previously realized.”

The study appears in the Proceedings of the National Academy of Sciences.

A Fulbright Canada STEM Graduate Award and a Natural Sciences and Engineering Research Council-CREATE fellowship to Gold, and a Foundation Grant from the Canadian Institutes of Health Research and a Canadian Institute for Advanced Research Senior Fellowship to Zatorre funded the research.

Source: McGill University