As schools around the country have rolled out one-to-one computer initiatives, handing out tablets and laptops to their students, a sour note has often intruded on the triumphant fanfare heralding these programs. Within days, even hours, of the devices’ distribution, their young users have figured out how to circumvent the filters meant to block access to games, social networking, and other noneducational activities (not to mention offensive or inappropriate content).

In Greenwood, Indiana, hundreds of students managed to reprogram their school-issued tablets on the same day they received them. In Los Angeles, where the school district has begun giving out a planned 600,000 iPads, entrepreneurial students sold a workaround to classmates for $2 a pop. And in Cherry Hill, New Jersey, a middle school pupil had a ready answer when his father, Thom McKay, asked him how he got on Facebook even though his school had banned it. “Pretty easy, Dad,” his son replied, as quoted in the New York Times. “Don’t be an idiot. We know more about computers than the teachers do.”

Even as students are reveling in their abilities to evade their schools’ Internet blocks, teachers are growing frustrated that they can’t get around those same firewalls (perhaps confirming the middle schooler’s acerbic observation). Educators’ online forums and Twitter accounts are filled with complaints that inflexible filters prevent them from using computers in creative and innovative ways in their classrooms. YouTube videos of famous speeches, Skype conversations with experts outside the school, collaborative tools that would allow students to annotate a shared text: access to such resources is cut off, teachers lament, by heavy-handed Internet controls.

School librarians, too, have joined the fray, mounting a moral crusade against the filters. The American Association of School Librarians has named an annual Banned Websites Awareness Day, drawing an explicit comparison between blocked websites and that righteous cause of freethinkers, censored books.

Since students are sidestepping them, teachers are feeling thwarted by them, and librarians are decrying their “overly restrictive filtering,” shouldn’t we consider knocking down school firewalls altogether?

It’s a question that applies to most American schools; 98 percent filter the online content available to students, according to a national longitudinal survey conducted by the AASL. The Children’s Internet Protection Act, a law passed by Congress in 2000, requires public schools that receive broadband access at a federally discounted rate (that’s almost all of them) to protect young people from online content that is obscene or otherwise “harmful to minors.” Nervous school administrators have additional reasons to install the filters: worries about cyberbullying, security breaches, illegal file sharing, scammers, and spammers.

The survey by the school librarians’ association, however, points to a less lurid reason to restrict students’ access to the Web: According to the AASL, schools’ top three filtered content areas are social networking sites, instant messaging and online chatting, and games. Such activities aren’t (necessarily) inappropriate or illegal, but they are big honking distractions, and if we want our young people to learn anything during the school day, they must be kept away from these sites.

A growing body of evidence from cognitive science and psychology shows that the divided attention typical of people engaging in “media multitasking”—the attempt to pay attention to two or more streams of information at once—produces shallower, less permanent learning. And let’s not kid ourselves: When students are free to roam the Internet in class or in study periods, divided attention is the result.

Is it possible to use Facebook and Twitter in educationally appropriate ways? Sure—but as technology and education specialist Michael Trucano points out, tech enthusiasts often focus on what’s possible to the exclusion of what’s predictable and what’s practical. What is predictable is that young people, given the chance, will use the Web for social and entertainment purposes; what’s practical is to remove that temptation during the school day. Even successful professional adults often need to tie themselves to the mast to get hard work done in the face of the Internet’s endless enticements: Novelists like Dave Eggers and Zadie Smith have said publicly that they use software that restricts their access to the Web while they’re writing.

Proponents of loosening school Internet filters often insist that educators have to “meet students where they are”—that is, in a world utterly saturated by technology. Actually, that saturation is an argument in favor of tightening students’ access to tech, of supplying in their formal education what they are not getting in their digitally dominated “informal education.”

As UCLA professor Patricia Greenfield has written, “The informal learning environments of television, video games, and the Internet are producing learners with a new profile of cognitive skills. This profile features widespread and sophisticated development of visual-spatial skills, such as iconic representation and spatial visualization.” (By “iconic representation,” she means the ability to understand the symbolic meaning of pictorial images like the icons that dot our computer screens.)

Greenfield continues: “Formal education must adapt to these changes, taking advantage of new strengths in visual-spatial intelligence and compensating for new weaknesses in higher-order cognitive processes: abstract vocabulary, mindfulness, reflection, inductive problem solving, critical thinking, and imagination.” We need, says Greenfield, to help students “develop a complete profile of cognitive skills”—and doing so requires time away from screens.

Critics of school firewalls also claim that they create a contrived and artificial environment, ill-suited to preparing students for the “real world” beyond such barriers. But, of course, the purpose of school is to be just such a protected place, set off from the rest of society. We create special physical spaces and staff them with special people—teachers—in order to train young people to handle the untrammeled “real world” in a thoughtful way.

We also employ teachers to guide students’ attention to what is important, which is why the school librarians’ likening of blocked websites to banned books is in most cases absurd. A blocked social networking site is less like a censored text and more like a teacher who tells students to stop passing notes and focus on their work. When Internet-connected computers are passed out, educators must continue—indeed, redouble—such efforts to direct students’ attention in fruitful, productive ways. This crucial responsibility should not be handed over to IT staff or school district lawyers—or worse, to software manufacturers who’ve never met a school’s faculty or students.

Internet filters are one conduit, albeit an imperfect one, through which educators convey their sense of what is meaningful and valuable to know. They represent a series of judgments and decisions, which ought to be made (though often are not) in a communal fashion. Teachers and administrators together should give careful thought to what is let inside the school walls and what is kept out, to what they view as enlightening and what they deem ephemeral. These choices should be integrated into a curriculum that instructs students on how to engage safely and effectively with the Internet, on how “to use the filters sitting on their shoulders,” as Web expert Nancy Willard puts it. And, finally, schools’ Web controls must be at least as smart as the most mischievous members of the student body—so that educators’ considered choices aren’t undone in a moment by ingenious but still undeveloped kids.

This story was produced by the Hechinger Report, a nonprofit, nonpartisan education-news outlet based at Teachers College, Columbia University.