Michael S. Rosenwald is a reporter for The Washington Post. Visit his blog, Rosenwald, Md., at washingtonpost.com/blogs/rosenwald-md .

It has been more than a month since Adam Lanza marched into Sandy Hook Elementary School and massacred 20 children and six adult staff members before taking his own life. Since that day, a massive debate over guns has gripped the country. President Obama has announced new measures to reduce gun violence. A Connecticut school was just named for one of the fallen teachers. And the Sandy Hook students are back in class.

Yet we still know next to nothing about the guy who caused it all.

Lanza’s former classmates and friends of his mother — whom he killed in her bed before embarking on the school massacre — have offered tantalizing clues. Lanza might have had Asperger syndrome, which is on the autism spectrum. He excelled at computers, putting them together and taking them apart. He played video games in his basement. He read a lot.

I was one of many reporters who descended on Newtown, Conn., after the tragedy. For several days, journalists tripped over one another at local video game stores, computer repair shops, a comic book store — just about any place where Lanza might have, perhaps should have, been known. But nobody knew him. Nobody had even seen him. Lanza was just a picture on the news. Even in life, he had been a ghost.

(Mark Allen Miller for The Washington Post)

The only person who recalled dealing with him was the town hairstylist, who had trimmed Lanza’s hair. Think about that: Except for using the bathroom and eating his meals, getting a haircut was just about the only thing Lanza couldn’t do online. All the things he apparently enjoyed were accessible to him without leaving his room. He could find community among gamers. He could order computer parts. He could buy books without ever visiting a bookstore. That he smashed his hard drive before the shooting spree was telling — a digital suicide preceding his physical one.

Police have yet to give a full report on Lanza and the shootings. There is more to be learned, more lessons to be drawn, more proposals that will be delivered beyond the ones Obama issued Wednesday, which include an assault-weapons ban and expanded background checks before gun purchases. But this case should also force us to confront yet again the ways in which ever more of our lives are lived on a screen, in the cloud, via our computers and phones and tablets, and soon, if Google has its way, through our glasses. Our lives are becoming more transmitted than lived.

I come to this not as a Luddite but as a gadget-obsessed freak who stands in line on Apple’s product-release days. Yet I see in my life the ways technology enables us to live alone together, connecting less with the breathing humans around us and more with data and digital humans on a screen. “Alone Together” is the title of a searing book published in 2011by Sherry Turkle, an MIT professor who has studied our computing lives for more than two decades. “Our networked life,” she writes, “allows us to hide from each other, even as we are tethered to each other.”

When I called Turkle to talk about Lanza, her response was simple: “He’s my guy. These are my people.”

By that she meant someone who seems to have found “an illusion of companionship without the demands of friendship,” she told me. Lanza didn’t need to trek out into his town because his community, from the hints we’ve gotten, was connected to a modem.

Turkle found the destruction of the hard drive particularly telling. “It was where he sought nurturance, but ultimately, it didn’t sustain him,” she said. “It’s not sustaining. It’s not life. It’s just not the same thing as life.”

And it’s not just that Lanza might have found a community of like-minded gamers to play and communicate with. Shop owners in tightknit Newtown didn’t know him, I think, because he had no reason to know them. Amazon could deliver anything he wanted to his door by the next day.

The time we spend shopping is in decline, according to the American Time Use Survey. The local stores we once loved visiting have been replaced by UPS drivers we rarely see, let alone talk to. The data flying through the air in digital bits become a bubble, and we feel less and less like breaking through it. Who really needs the hassle of, you know, leaving the house?

Many others who study the Internet find such arguments spurious. They point to findings such as a 2009 Pew Research Center study showing that social isolation hadn’t changed much since 1985. “Some have worried that internet use limits people’s participation in their local communities,” researchers wrote, “but the Pew Internet report finds that most internet activities have little or a positive relationship to local activity. For instance, internet users are as likely as anyone else to visit with their neighbors in person.”

University of Toronto sociologist Barry Wellman is decidedly not on Turkle’s side. In a paper titled “Social Connectivity in America: Changes in Adult Friendship Network Size From 2002 to 2007,” Wellman found “that friendships continue to be abundant among adult Americans between the ages of 25 to 74 and that they grew from 2002 to 2007.” Of course, fewer than 100 million people were on Facebook in 2007 — it has more than 1 billion members now — and gadgets weren’t nearly as ubiquitous as they are today.

Still, Wellman told me that “we know that the more people are online, the more friends they have,” an argument he makes in a new book he co-wrote called “Networked: The New Social Operating System.” Technology increases our opportunities for meaningful connections near and far, and while the assumption might be that it will — like the original phone, the one with a cord — leave us all homebound in our bathrobes and hair curlers, he has not found that to be true.

So what about Lanza?

“There are exceptions to every rule,” he said. “It does occur, but it’s not the common situation.”

And we cannot forget about the Asperger’s component to Lanza’s story. People with this syndrome typically withdraw from social situations and have difficulty forming connections with people. I recently got in touch with Jason Nolan, who studies social technologies at Ryerson University in Toronto and has autism. He preferred to be interviewed by e-mail, so I sent him a note asking about social isolation and computer use for people on the autism spectrum. He sent back a long and thoughtful reply.

“Finding others like ourselves close to home isn’t always easy, especially in what are referred to as ‘close knit’ communities that are defined by social, cultural or ideological consensus rather than diversity,” Nolan wrote. “This is why a lot of us who cannot find community in our so-called communities seek out friends and allies online. Social technologies can be a lifeline for anyone who is unable to find the support they need in their face-to-face community.”

We don’t know whether Lanza had a Facebook account. One hasn’t come up publicly, but he could have used a different identity. He could have been a lurker on social and gaming networks — another form of connecting to a community. But for better or worse, Nolan suspects that Lanza’s computer became a crucial component of his character.

“Given his love of computers and digital technologies such as video games,” Nolan wrote, “Adam Lanza’s decision to destroy his hard drive may simply have been his first act of self-annihilation, especially if he regarded his computer as an extension of himself and his identity.”

In Lanza’s case, though the hard drive and the human soul seemingly became intertwined, the difference was apparent after their deaths.

A hard drive is replaceable. A human being is not.

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