There was a time, during the 1950s, when the drivers of Volkswagen Beetles would give each other a friendly beep of the horn when they passed on the street. That gesture recognized a fellow member of an exclusive society, someone with the wit and style to embrace the iconic and vaguely anti-establishment VW Bug (even if many bought them just because they were cheap). Although it’s hard to imagine anything less high-tech than the Beetle, that beep of the horn and the iPod nod share the same roots. When strangers sporting those telltale white earbuds and dangling cord silently greet each other on the street, they’re acknowledging membership in the same club.

But they’re also showing they’re hip enough to own what Michael Bull, a sociologist and leading expert on music’s cultural impact, has called “the 21st century’s first consumer icon,” one that is altering the way many of us experience our urban environments.

There’s no doubt that Apple’s iPod is a cultural phenomenon. With millions of devices sold since its launch in 2001, the sleek little box is part of a $3-billion worldwide mobile music industry, which is dominated not only by cellphone ring tones but also the growing full-track segment that features entire songs or albums.

The company’s now-ubiquitous global advertising campaign shows silhouetted figures with dangling cords dancing to their own private rhythm, together and yet alone. These are the iPod People, and the stylized imagery neatly symbolizes a cultural controversy. Are iPods inherently anti-social, encouraging people to disengage from the world around them? Do urban centres become less civilized, perhaps even less safe, with so many people retreating into a bubble of music? In early 2005 in New York City, for instance, there was a marked increase in theft on subways, partly attributed to distracted iPod users who found their precious devices snatched out from under them. Or is the whole debate, which sounds like a topic for a Culture: Good or Bad panel on a TV news show, missing the point?

Michael Bull, a professor at Sussex University in England and the leading authority on mobile music, thinks he knows the answer. Bull studied Sony Walkman users a decade ago, and this fall Routledge will publish his book, based on interviews with more than 1,000 iPod users. Bull says digital music players offer a kind of urban shield against a barrage of people and of noise and visual pollution. Their popularity, he explains, “indicates a heightened desire to control the space in which we live. While I think it’s true that iPod users inhabit their own reality, it’s naively romantic to believe that strangers would strike up conversations.”