One paragraph stopped me in my tracks:
There was one truth, though, that connected the McGill music men's work to Choueiri's: the vital role of the not-too-perfect in our pleasures. The two expressive dimensions whose force in music Levitin had measured and made mechanical were defections from precision. Vibrato is a way of not quite landing directly on the note; rubato is not quite keeping perfectly to the beat. Expressiveness is error. Just as, at a subliminal level, Choueiri could make music come alive in space by introducing tiny errors into the amplitude and timing of the XTC wave, Levitin could show that what really moves us in music is the vital sign of a human hand, in all its unsteady and broken grace. (Too much imperfection and it sounds like a madman playing; too little, and it sounds like a robot.) Ella singing Gershwin matters because Ella knows when to make the words warble, and Ellis Larkins knows when to make the keyboard sigh. The art is the perfected imperfection.
I recently had an experience that underlined this point. While deciding what music to put on the system in my office, I chose an album that I very much liked a few years ago, "Leaves in the River" by the musician Sea Wolf. For some reason it sounded a bit sterile, muted, not quite as I remembered it. Then I realized I had another Sea Wolf item in my collection, a live podcast from that same time. I listened to that, and it sounded richer, more organic. More enjoyable.
The Sea Wolf podcast was recorded live, so it was imperfect, less constructed, "looser" both in tempo and intonation. Many of the terms we use to describe music, Gopnik points out, such as rubato and vibrato, are actually descriptions of tiny imperfections. Musicians also experience technical limitations the inability to sound a pitch perfectly, or a certain way of strategically leaving out notes in a difficult passage. All these, added together, become something we call "voice." Voice is what makes one person's playing instantly recognizable; the mistakes make all the difference.
[Thanks to Cynthia Kurtz for pointing out the article.]
Bonus: here's a "perfectly imperfect" newer live song from Sea Wolf: