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

by Daniel J. Levitin

When I was in graduate school, my advisor, Mike Posner, told me about the work of a graduate student in biology, Petr Janata. Although he hadn’t been raised in San Francisco like me, Petr had long bushy hair that he wore in a ponytail, played jazz and rock piano, and dressed in tie-dye: a true kindred spirit. Peter placed electrodes in the inferior colliculus of the barn owl, part of its auditory system. Then, he played the owls a version of Strauss’s “The Blue Danube Waltz” made up of tones from which the fundamental frequency had been removed. Petr hypothesized that if the missing fundamental is restored at early levels of auditory processing, neurons in the owl’s inferior colliculus should fire at the rate of the missing fundamental. This was exactly what he found. And because the electrodes put out a small electrical signal with each firing—and because the firing rate is the same as a frequency of firing (as we saw above)—Petr sent the output of these electrodes to a small amplifier, and played back the sound of the owl’s neurons through a loudspeaker. What he heard was astonishing; the melody of “The Blue Danube Waltz” sang clearly from the loudspeakers: ba da da da da, deet deet, deet deet. We were hearing the firing rates of the neurons and they were identical to the frequency of the missing fundamental. The overtone series had an instantiation not just in the early levels of auditory processing, but in a completely different species.