The Science Of DJing

Virginia Gewin checks in with a couple of scientists who bring data to the dance floor:

It may just seem like people having simple fun at a club, but there’s something deeper going on. “We use the crowd to communicate with each other,” says [DJ Johan] Bollen. “We’re encoding information in the crowd.” Bollen cites a technical term for this: stigmergy, a form of indirect coordination of actions. The term describes, for example, how ant colonies make effective “decisions” in complicated situations, even though each ant’s behavior is very simple. The ants use pheromones to exchange information; the environment serves as their shared memory. Complexity spontaneously emerges from simplicity.

Bollen and [Luis] Rocha are experts on stigmergy—for real.

They DJ by night, but by day they study cybernetics—how people, animals, and machines control and exchange information—at Indiana University in Bloomington. A focus on feedback runs through their both their research and DJing. And while they really just want to orchestrate a raging party, the crowd is, in a sense, an experiment. …

Songs are categorized along two primary dimensions: energy level (bpm) and “valence”—the feeling of the music, consisting of a spectrum of universal emotions, from dark or edgy (cold) to inviting or velvety (warm). At [a] February show, for example, Bollen picked up on the crowd’s vibe, ramped up the energy level, and, at 124 bpm, played “The Feeling” by Eden—a warm, inviting song that signaled that the party was truly underway. “Our research—the notion of feedback and complex systems—informs everything we do,” says Bollen. “A DJ and an audience are a cybernetic system, controlling each other’s state.”

(Video: Live mash-up of “Pop Culture” by Madeon)