THE SONG DECODERS 5

And why is that? Surely no one consciously says, “My cool friends like the new Jack White, so I’ll memorize the lyrics and pretend to like it, too, for sociocultural reasons.” Yet the research about how listeners link musical taste (at least at a genre level) and identity is extensive. Surely that’s one reason so much of digital music culture is devoted to opportunities to “share” your taste: the endless options for posting playlists, recommending songs, displaying what you are listening to now, announcing your favorite artists.

Maybe the more vivid illustration of social influence on listening habits isn’t in what we share but in what we obfuscate. Last.fm, for example, publishes a chart listing the songs that its users most frequently delete from their public listening-stream data. The guilty pleasure Top 10 is dominated by the most radio-ready pop artists — Katy Perry’s “I Kissed a Girl,” several tracks by Lady Gaga. The service iLike compiles similar data on the most “suppressed” songs its users listen to in secret; Britney Spears figures prominently. Apparently even listeners who can set aside certain cultural information long enough to enjoy something uncool would just as soon their friends didn’t know. Maybe even in our most private listening moments, what our peers think matters.

Much attention has been focused in the last few years on studying music-liking at the brain level. Daniel Levitin, a neuroscientist (and musician) has been one of the high-profile thinkers in this area, by way of his popular books “This Is Your Brain on Music” and “The World in Six Songs.” One of his central themes is that pretty much all humans are wired to enjoy music, and he says he believes musicality is even important to the evolution of the species.

But when you start talking about individuals, instead of humanity in general, universals are a lot harder to come by. Much depends on culture. The emotions expressed in many of those ragas that Pandora’s experts are presently decoding, for instance, are lost on the typical Westerner. Just as we’re hard-wired to learn a language, but not to speak English or French, our specific musical understanding, and thus taste, depends on context. If a piece of music sounds dissonant to you, it probably has to do with what sort of music you were exposed to growing up, because you were probably an “expert listener” in your culture’s music by about age 6, Levitin writes.

The cliché that our musical tastes are generally refined in our teens and solidify by our early 20s seems largely to be true. For better or worse, peers frequently have a lot to do with that. Levitin recalled to me having moved at age 14 and falling in with a new set of friends who listened to music he hadn’t heard before. “The reason I like Queen — and I love Queen — is that I was introduced to Queen by my social group,” he says. He’s not saying that the intrinsic qualities of the music are irrelevant, and he says Pandora has done some very clever and impressive things in its approach. But part of what we like is, in fact, based on cultural information. “To some degree we might say that personality characteristics are associated with, or predictive of, the kind of music that people like,” he has written. “But to a large degree it is determined by more or less chance factors: where you went to school, who you hung out with, what music they happened to be listening to.”

Pandora’s approach to listening violates at least three pieces of conventional digital-music wisdom: it rejects the supremacy of social-data taste communities; it shrugs off the assumption that contemporary listeners must have instant on-demand access to any single song; and, most striking, it rejects what many observers see as a given, which is that music consumers are fundamentally motivated by access to the most massive pool of songs possible. Slacker.com, a rival Internet-radio service, says its library contains about 2.5 million songs. Spotify, the European music streaming service, expected to be available in the U.S. by early next year, is generating enormous buzz because of it offers free, on-demand access to more than 5 million tunes.

Pandora’s 700,000-song library sounds puny by comparison. And yet the service has millions of devoted listeners. Why? One answer, perhaps, involves the ways that the genome, quietly, doesn’t really screen out sociocultural information. For instance, its algorithms are tweaked by genre, and the inclusion of genes for “influence” (“swing” or “gospel,” for example) brings in factors that aren’t strictly about sound. And Pandora’s algorithm does adjust if, for instance, users routinely thumbs-down a particular song under similar circumstances, meaning the genome’s acoustic judgment can at times be trumped by crowd taste. But the biggest cultural decision of all may be the one that also happens to guide Westergren’s response to the issue of scale: how, exactly, does a given piece of music get into Pandora’s system anyway?