"The Shazam Effect: Record companies are tracking download and search data to predict which new songs will be hits. This has been good for business—but is it bad for music?"

...But here’s the catch: if you give people too much say, they will ask for the same familiar sounds on an endless loop, entrenching music that is repetitive, derivative, and relentlessly played out. Now that the Billboard rankings are a more accurate reflection of what people buy and play, songs stay on the charts much longer. The 10 songs that have spent the most time on the Hot 100 were all released after 1991, when Billboard started using point-of-sale data—and seven were released after the Hot 100 began including digital sales, in 2005. “It turns out that we just want to listen to the same songs over and over again,” Pietroluongo told me. Because the most-popular songs now stay on the charts for months, the relative value of a hit has exploded. The top 1 percent of bands and solo artists now earn 77 percent of all revenue from recorded music, media researchers report. And even though the amount of digital music sold has surged, the 10 best-selling tracks command 82 percent more of the market than they did a decade ago. The advent of do-it-yourself artists in the digital age may have grown music’s long tail, but its fat head keeps getting fatter. Radio stations, meanwhile, are pushing the boundaries of repetitiveness to new levels. According to a subsidiary of iHeartMedia, Top 40 stations last year played the 10 biggest songs almost twice as much as they did a decade ago. Robin Thicke’s “Blurred Lines,” the most played song of 2013, aired 70 percent more than the most played song from 2003, “When I’m Gone,” by 3 Doors Down. Even the fifth-most-played song of 2013, “Ho Hey,” by the Lumineers, was on the radio 30 percent more than any song from 10 years prior.

...The problem is not our pop stars. Our brains are wired to prefer melodies we already know. (David Huron, a musicologist at Ohio State University, estimates that at least 90 percent of the time we spend listening to music, we seek out songs we’ve heard before.) That’s because familiar songs are easier to process, and the less effort needed to think through something—whether a song, a painting, or an idea—the more we tend to like it. In psychology, this idea is known as fluency: when a piece of information is consumed fluently, it neatly slides into our patterns of expectation, filling us with satisfaction and confidence. “Things that are familiar are comforting, particularly when you are feeling anxious,” Norbert Schwarz, a psychology professor at the University of Southern California, who studies fluency, told me. “When you’re in a bad mood, you want to see your old friends. You want to eat comfort food. I think this maps onto a lot of media consumption. When you’re stressed out, you don’t want to put on a new movie or a challenging piece of music. You want the old and familiar.”

... One of the popular songs of this past summer, “Problem,” combined a dizzy sax hook, ’90s-pop vocals, a whispered chorus, and a female rap verse. It was utterly strange and, for a while, ubiquitous. Greta Hsu, an associate professor at the University of California at Davis, who has done research on genre-blending in Hollywood, told me that although mixing categories is risky, hybrids can become standout successes, because they appeal to multiple audiences as being somehow both fresh and familiar.

Music fans can also find comfort in the fact that data have not taken over the songwriting process. Producers and artists pay close attention to trends, but they’re not swimming in spreadsheets quite like the suits at the labels are. Perhaps one reason machines haven’t yet invaded the recording room is that listeners prefer rhythms that are subtly flawed. A 2011 Harvard study found that music performed by robotic drummers and other machines often strikes our ears as being too precise. “There is something perfectly imperfect about how humans play rhythms,” says Holger Hennig, the Harvard physics researcher who led the study. Hennig discovered that when experienced musicians play together, they not only make mistakes, they also build off these small variations to keep a live song from sounding pat.