Conrad Lee, AB’07, assumed major cities such as New York and London were the arbiters of musical taste, that listeners there tended to be trendsetters in identifying popular songs and artists. To test that theory—and to chart how preferences spread through social networks—Lee, a computer scientist at University College Dublin, and his supervisor, Pádraig Cunningham, analyzed almost three years of information from the music-recommendation website last.fm.

Using billions of data points that charted the top 500 artists in more than 200 cities, they adapted a method “previously used to detect the leadership networks present in flocks of birds,” they reported in their April arXiv paper, “The Geographic Flow of Music.” Plotting how many unique users in a given city listened to certain performers, they placed the cities in “artist space”—comparable to the position of birds in flocks. “We find empirical support for the claim that a similar leadership network exists among cities.”

Leadership, Lee noted in an online post about the research, does not necessarily imply influence. “We don’t know the mechanism that causes some cities to appear to follow other cities”—whether followers genuinely imitate leaders or if other factors, such as music-industry marketing or tour schedules, come into play.

The results, which Lee emphasizes are preliminary, surprised him: Atlanta and Oslo were the overall leaders. Looking at individual genres, the researchers found Paris and Montreal ahead in indie music. For North American hip-hop, Atlanta, Toronto, and Chicago were the trendsetters. Overall, and in different genres, New York and London fell in the middle of the pack.

Adapting a method used to detect leadership networks in flocks of birds, researchers charted musical trendsetters in the 20 most active North American cities: