In 1998, Scott Campbell was working for Sprint PCS in Kansas City. The cell phone company had recently launched America’s first digital network, and Campbell was developing new services for it. While excited about the opportunity to let customers share data as well as phone calls, he remembers, “we didn’t think it would be a daily resource. We didn’t have any idea what was coming.”

That changed one day at lunch. It was Taco Tuesday, and at the restaurant, he was startled to notice that before his companions dug into their meals, every one of them pulled out a cell phone and set it on the table. That got him thinking about how dramatically mobile connections might reshape people’s lives. At that moment, he says, “I knew I was going to graduate school and study this.”

An energetic University of Nebraska grad with math smarts, Campbell earned advanced degrees in communications from the Universities of Missouri and Kansas. His concentration was the social impact of mobile networks. The concept was so new that he had trouble assembling a committee to supervise his dissertation, but he earned his doctorate in 2002 and was hired to teach at Hawaii Pacific University.

Not long afterward, cell phone pioneer Arnold Pohs and his wife, Constance, who met as U-M undergrads, wanted to support telecommunications studies at the university. When the communications department looked for established scholars to fill an endowed chair, though, they had trouble finding any. The position had to be reposted for junior faculty–which is how Campbell got the job in 2005.

“Scott has been one of the pioneers in the field,” says U-M communications chair Susan Douglas. “When he began this research ten years ago, hardly anyone was studying the impact [of mobile communications]. Initially it was hard for him to get his work published in academic journals because no one was paying attention.”

As the field grew around him, Campbell, now forty-five, became a prolific author, of journal articles. (The field changes so fast, he says, that book-length studies can be obsolete by the time they’re printed.) He got tenure in 2011 and now fields reporters’ questions on subjects ranging from Facebook dating trends to texting while driving (frighteningly, parents do it as often as their teenagers). He’s researched mobile communication and voting patterns in South Korea and recently organized a conference that explored how cell phones can empower workers in Third World countries.

He knows he’s riding a big wave. “We’ve never seen any other kind of technology diffuse so fast and so widely as mobile communication,” he says. “Ever.”

In class one Monday morning in North Quad, Campbell, in a gray pullover and jeans, uses PowerPoint to romp briskly through different cultural eras–the Romantics, Modernism, and more. He is reinforcing to this class of graduating seniors the idea that they’re living in the Digital age. When I ask the students about their experience with mobile media, one says that texting her friends can “bring us close” without narrowing their world–“we still spend time on very global concerns.” At the opposite extreme, another student startled the class by saying she texted so much it was stressing her out. “She downgraded to a flip phone,” Campbell reports, “which she has to press three or four times [to type each letter]. She feels much more free.”

During class, a few students appear to be sending private texts. Asked about it later, Campbell acknowledges that he’s struggled with the irony of students using mobile media to zone out of a class on the subject. He used to warn students that if their phone rang in class, he reserved the right to answer it–but stopped doing that, shaken, after picking up a call from a student’s depressed boyfriend.

He still sometimes confronts texting students by making their behavior part of the class discussion. But he’d never demand they turn their phones off. For the digital generation, he says, their phone is “part of their identity … it’s like taking away their wallet with their Social Security card in it.”

That sensitivity may partly explain why Campbell is a popular prof. “A pretty cool and relaxed guy,” writes one U-M student on Another advises that the dark-haired marathon runner is “GREAT TO LOOK AT.”

Campbell is alert to the downsides of today’s connected world. He starts each semester by having his undergrads read a Kurt Vonnegut short story, “Confido.” It’s about an invention that seems able to read minds–with sinister consequences. He asks the students if they see any parallels to their dependence on smartphones–and says “they are always able to make interesting connections.”

Campbell says the question he finds most compelling is, “What is this [immersion in mobile media] taking away from?” Though many people are concerned that it’s reducing direct interaction, Campbell says his research findings don’t support that; even heavy users of mobile media make time to meet face-to-face. He worries, though, that being in constant contact shrinks “those moments of time that you quietly reflect on things by yourself.”

Campbell makes sure parts of his own life remain low tech. He takes banjo lessons–“an outside activity where I don’t have to get plugged in”–and cultivates friendships with academics in other disciplines. And after his wife, Faith Sparr, gave birth to their son, Fletcher, seven years ago, he says, “I became much more aware of how much I was using my phone.” With certain exceptions (like making plans with Sparr, a lawyer who teaches communications law), he keeps his cell off when playing with their son.

He’s pleased, though, that Fletcher asks him to look on his cell phone or computer to answer questions–like, “Who was the first person ever born?” He says his son boasts to friends, “My daddy is a cell phone doctor.”