This Is Your Brain on Music: The Science of a Human Obsession

“Schema,” or frameworks formed on the basis of past experience, guide one’s expectations for a piece of music. The brain creates these schema by extracting features from past examples of similarly categorized experiences and stimuli, identifying essential components, and combining them into sets of expectations for future experiences. Skilled composers are like magicians, deliberately establishing and then violating expectations to evoke emotions in their audience. To do this, they use practically all characteristics of music, including timbre, rhythm, chord progression, meter, and even genre. The composer Haydn was particularly fond of deceptive cadence, a well-used illusion in Western music wherein a piece’s chord progression diverges unexpectedly from its established sequence to signal that the piece is not yet finished. Many modern classical composers base their pieces on new and unfamiliar scales, removing expectation and resolution from their music entirely and thereby leaving both the performers and audience ungrounded. Melody is one of the main channels by which composers control and diverge from audience expectations. In the principle of “gap fill,” for example, if a melody makes a large leap in pitch, the audience expects the next note to change direction toward the jump-off point. Postponing the resolution toward the starting or “home” note builds suspense as the audience awaits the melody’s resolution.

Precisely mapping functions of the brain to different regions is difficult, although scientists glean some information from observing the cognitive functions that damage to different areas affects. The brain does not contain an isomorphic representation of the world; instead, it stores sensory information in neural codes, similar to how computers store auditory and visual information in binary format. The primary cells of the brain and the nervous system are neurons. When they fire, they send electrical impulses across the synapses between them, causing the release of chemicals. These neurotransmitters bind to receptors on other neurons, causing them to either fire or not fire. One such neurotransmitter, dopamine, links to feelings of pleasure, and Levitin and his colleagues recently proved its role in processing music.

Cognitive scientists can track the firing of neurons using an electroencephalogram (EEG), although the technological limitations of this method significantly hinder the precision of its data. On a macro level, some brain functions are lateralized between the brain’s hemispheres, and reality is significantly more nuanced than the common beliefs about specialization in the left or right side of the brain indicate. Levitin and his colleagues have used functional magnetic resonance imaging (MRI) to observe the activation of different regions of the brain by tracking blood flow in order to investigate the differentiation hypothesis. This hypothesis proposes that in infants, the same neurological systems initially process both music and language. As an infant matures, differentiation occurs so that the brain processes music and language independently (at least to some extent). They discovered significant overlap between the regions of the brain that process music and those that process language, but they also found that certain areas activate only when processing music. This neurobiological evidence supports the differentiation hypothesis and also suggests that some regions of the brain are dedicated to processing and predicting structure over time, regardless of the mode of sensory input.