Neuroscience of music: why we like surprising melodies

From one of my favourite blogs, Jonah Lehrer’s The Frontal Cortex (and by the way, someone that smart should not be that good looking. No fair!) comes a post about a fascinating new piece of research on the neuroscience of music. As the authors write in their abstract:

In this study, we investigated melodic pitch expectations elicited by ecologically valid musical stimuli by drawing together computational, behavioural, and electrophysiological evidence. Unlike rule-based models, our computational model acquires knowledge through unsupervised statistical learning of sequential structure in music and uses this knowledge to estimate the conditional probability (and information content) of musical notes. Unlike previous behavioural paradigms that interrupt a stimulus, we devised a new paradigm for studying auditory expectation without compromising ecological validity.

What does all this mean? Lehrer explains:

The paper consists of a computational model and and an experiment. The model essentially demonstrated that statistical predictions based on our personal listening experience – because I listen to Bruce Springsteen, I’m able to predict the melodies of John Mellencamp – was much better at simulating the mind than a rule-based model, in which our expectations are fixed and inflexible.

The experiment was more compelling. The scientists measured the brain waves of a twenty subjects while they listened to various hymns. It turned out that unexpected notes – pitches that violated the previous melodic pattern – triggered an interesting sequence of neural events and a spike in brain activity …

There are two interesting takeaways from this experiment. The first is that music hijacks some very fundamental neural mechanisms. The brain is designed to learn by association: if this, then that. Music works by subtly toying with our expected associations, enticing us to make predictions about what note will come next, and then confronting us with our prediction errors. In other words, every melody manipulates the same essential mechanisms we use to make sense of reality.

The second takeaway is that music requires surprise, the dissonance of “low-probability notes”. While most people think about music in terms of aesthetic beauty – we like pretty consonant pitches arranged in pretty patterns – that’s exactly backwards. The point of the prettiness is to set up the surprise, to frame the deviance. (That’s why the unexpected pitches triggered the most brain activity, synchronizing the activity of brain regions involved in motor movement and emotion.)

Fantastic stuff. ScienceBlogs is going from strength to strength at the moment.

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