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

by Daniel J. Levitin

One could imagine an alien species that does not have ears, or that doesn’t have the same internal experience of hearing that we do. But it would be difficult to imagine an advanced species that had no ability whatsoever to sense vibrating objects. Where there is atmosphere there are molecules that vibrate in response to movement. And knowing whether something is generating noise or moving toward us or away from us, even when we can’t see it (because it is dark, our eyes aren’t attending to it, or we’re asleep) has a great survival value. Because most physical objects cause molecules to vibrate in several modes at once, and because for many, many objects the modes bear simple integer relations to one another, the overtone series is a fact-of-the-world that we expect to find everywhere we look: in North America, in Fiji, on Mars, and on the planets orbiting Antares. Any organism that evolved in a world with vibrating objects is likely—given enough evolutionary time—to have evolved a processing unit in the brain that incorporated these regularities of its world. Because pitch is a fundamental cue to an object’s identity, we would expect to find tonotopic mappings as we do in human auditory cortex, and synchronous neural firings for tones that bear octave and other harmonic relations to one another; this would help the brain (alien or terrestrial) to figure out that all these tones probably originated from the same object.