BROOKE GLADSTONE: And I'm Brooke Gladstone. Five weeks ago on the British program Newsnight, the famously relentless host Jeremy Paxman tackled the issue that is eating away at good parents everywhere.

JEREMY PAXMAN: I've got a child who uses a social networking site like Facebook or Twitter or something. Who hasn't, you might say? Well, their brain’s being rotted, or at least that’s more or less what The Daily Mail claimed this morning. The paper was citing Baroness Susan Greenfield who told us today that repeated exposure to screens could rewire the brain.

BARONESS SUSAN GREENFIELD: It follows if the human brain is so impressionable, if the environment is changing, then the brain might change too. There is no evidence –

[BARONESS GREENFIELD/UP AND UNDER]

BROOKE GLADSTONE: The baroness, a neuroscientist at the University of Oxford, willingly conceded that the problem, in the absence of any actual proof, was still theoretical, but then caused a ruckus by just as willingly speculating on the psychological damage posed by long hours spent online.

BARONESS SUSAN GREENFIELD: - argue a shorter attention span, an emphasis on process, on the experience of the moment rather than content, of an identity that needs to be bolstered up with Twitter and perhaps an increased recklessness.

BROOKE GLADSTONE: Greenfield says the Internet is stunting our social development. A report in the British magazine Biologist claims it’s making us lonely. An article in last summer’s Atlantic asks -- is Google making us stupid. So what is the Internet doing to our brains? Inquiring minds want to know. Two years ago, writer John Lorinc suggested in the Canadian magazine The Walrus that the Internet is probably making our minds more inquiring, and not in a good way.

JOHN LORINC: I came across some studies that had identified these two terrifically descriptive terms, “informavores” and “information foraging,” when you’re working online. There is this craving for information. It’s difficult to know when to stop. And you can quickly come to the conclusion that you can go on link by link by link ad infinitum.

BROOKE GLADSTONE: Down the rabbit hole.

JOHN LORINC: Down the rabbit hole. You’re always waiting to get closest to some ideal of a perfect state of information? And, you know, in a pre-digital, pre-Internet environment, you could get to that place very quickly, whereas with the Internet I do think that the horizon is much further off, and yet you still crave that. And I do think that’s the addictive nature of it.

BROOKE GLADSTONE: The byproduct of information addiction is chronic distraction. And though there is, as yet, no hard data on the impact of the Internet, there is a vast body of work devoted to the consequences of constant interruption. Most of that research predates the Internet and yet, interruption defines our digital lives. We continually break away from one task to attend to another – an email, an instant message, a popup, a purchase, a quick detour offered by an intriguing link. We call it multitasking.

FRANK RUSSO: I would say that we don't actually multitask. We serial task.

BROOKE GLADSTONE: Frank Russo, director of the Science of Music Auditory Research and Technology Lab at Ryerson University, says that if we could do two tasks at once we wouldn't crash the car while talking on the phone. What we really do is flip back and forth, constantly breaking our mental flow.

FRANK RUSSO: So we might be entertaining a thought and we might be trying to think about, well, how does this fit with other things I know, how can I advance what I'm looking at and get to the next step. All of that hard cognitive work is taken away once we get that popup message. So if we're doing something that involves some sort of complicated thought, developing an argument of any kind, it’s not going to be as efficient if we have constant disruptions.

BROOKE GLADSTONE: So does that mean that Google is making us stupid?

FRANK RUSSO: We've been getting more intelligent, as assessed by standard intelligence tests, progressively over the last 50 years, so that’s the part I don't get, I have to say. Somehow we're getting more intelligent, but it’s also clear to me, just anecdotally, from my own experience, that people seem to have less tolerance for complex arguments. I don't know how those things add up.

GARY SMALL: At UCLA we recently did a study that we affectionately termed “Your Brain on Google.”

BROOKE GLADSTONE: Gary Small, director of the Memory and Aging Center at UCLA and author of iBrain: Surviving the Technological Alteration of the Modern Mind.

GARY SMALL: And [LAUGHS] what we did was to look at the brain in real time when it searches online, and we found that older people who had prior Internet experience showed a much greater degree of brain activity than those who were naive to the Internet search experience. So the headline became, “Google is Making Us Smart.” And I don't think it’s that simple. I think, in some ways, Google may be making us stupid because we spend not as much time thinking about issues in depth.

BROOKE GLADSTONE: Less depth, more breadth. There are tradeoffs with every new technology. Socrates complained that writing things down was bad for the memory. We hear that same complaint about digital technology. We can't remember phone numbers because they're stored in our cell phones. Boo-hoo. There is a limit to how much we can hold in our brains, isn't there?

GARY SMALL: You think? [LAUGHS]

BROOKE GLADSTONE: No, seriously. I mean, several have said that, you know, the brain functions like a computer. You have RAM. I think back on the things that are in my mind, taking up space, that I wish I could get rid of, like the theme song to The Patty Duke Show.

[THEME SONG/THE PATTY DUKE SHOW UP AND UNDER] I don't really need that anymore.

[THEME SONG IN BACKGROUND]

GARY SMALL: That’s haunting you too. [BROOKE LAUGHS] My God, what a coincidence.

[BROOKE LAUGHING] Now that you've said it, I'm going to be thinking of that the rest of the afternoon.

[THEME SONG CONTINUES/UP AND UNDER]

BROOKE GLADSTONE: [LAUGHS] But as a result, that’s a little bit of space that maybe I could have devoted to something useful, but I can't delete that memory. As somebody who knows so much about memory, the fact that you can offload some of these unnecessary bits of flotsam is a good thing; it expands our capacity, right?

GARY SMALL: That's right. And we don't need to remember a lot of these details. We need to know how to get the details.

BROOKE GLADSTONE: But we can't offload social skills, like we can phone numbers. What about the concern that constantly connecting through online social networks is rendering us less capable of connecting in real life? A recent British study found that the number of people saying that there is no one with whom they can discuss important matters nearly tripled in the last two decades. Lee Rainie directs the Pew Internet and American Life Project.

LEE RAINIE: In the data that we gather in our research, we don't see a lot of increased levels of loneliness, increased levels of isolation.

BROOKE GLADSTONE: Rainie’s project offers periodic updates on the future of the Internet.

LEE RAINIE: We see that people use the Internet and use their cell phones in an additive way. They add to the number of people that they interact with in the world, and they don't use those devices as substitutes for other kinds of human contact that are enriching and helping people’s lives. There are lonely people in the world. There are people who are inclined to withdraw from the world, and the availability of these technologies does help them stay isolated. But for the vast majority of people that we talk to and we look at in our research, they say these technologies are adding to their social well being and adding to the richness of their social lives.

BROOKE GLADSTONE: Psychiatrist Gary Small, who wrote the book iBrain, is among many experts who expect that someday holograms will be able to replicate the experience of meeting face to face. It’s also increasingly likely that the technology will give us a chance at a kind of intimacy we may never have thought possible, the ability to meet mind to mind.

GARY SMALL: We have a little illustration in iBrain where there are people wearing these little headband sensors where they can communicate with their handheld devices or laptops just by merely thinking about it. And those thoughts are wirelessly transmitted to their computers, so they can say to each other, just with their thoughts, “Let's meet at Starbucks” and not even have to talk.

BROOKE GLADSTONE: So the technology of the Internet will continue to redefine our personal relationships. But what about relationships on a societal scale, between political and religious groups, ethnicities and nations? Lee Rainie says that all the experts consulted by Pew agree that in a few years mobile devices will allow us to stay continuously connected to the Internet, but they're split 50/50 on whether that’s for the good. The optimists say:

LEE RAINIE: That the more we learn, the more we interact, the more that we discover about the world, it improves our lives and it improves the general social condition. We just get to know each other better, and good things happen because of that.

BROOKE GLADSTONE: The pessimists say:

LEE RAINIE: That our propensity to be nasty or propensity to shun those who are not in our in-group or the propensity for people to find just information that agrees with their world view, all of that will be amplified in this new world, and so we will become more isolated, more hard edged in our beliefs, and it will be a state of nature more than it will be Nirvana.

BROOKE GLADSTONE: A worry that’s long plagued media watchers – like me – is the echo chamber phenomenon in which likeminded people huddle in bubbles in the blogosphere where they never have to confront a conflicting opinion or unwelcome fact, where in defense of the dogma of the tribe, moderates are sidelined and extremists exalted. Rainie conducted a study of people’s politics on the Internet during the 2004 presidential campaign. He found that the echo chamber phenomenon is a byproduct of human nature, not the Internet. The Net merely amplifies what’s worst and best in us all.

LEE RAINIE: One of the surprising things we found in that survey was that those who are the most technologically adept and those who are the most engaged with information actually are not in the echo chamber pattern; they are actually seeking out and finding out more arguments opposed to their views than those who are less technologically adept and less interested in political information.

BROOKE GLADSTONE: Wait a minute, wait a minute. You have just blown my mind. [LAUGHS] So what you’re saying is that regardless of their political persuasion, the more comfortable they were in cyberspace, the more likely they were to know views across the spectrum and views other than their own.

LEE RAINIE: Right. They essentially behaved like information omnivores. They were soaking up all kinds of information in all kinds of ways. The people who worry about the echo chamber worry that people are going to narrow their universe, as information becomes more voluminous, that people, just as a coping strategy, will only look at the stuff that agrees with their point of view and only deal with the people who support their ideas. But, in fact, these omnivores, in particular, the most technologically adept people, are, you know, scanning every horizon they can, and they can't help but bump into stuff that doesn't agree with them.

BROOKE GLADSTONE: That’s a different response to information from what we’ve seen before. All the experts we spoke to believe that children growing up on the Net will be better at some kinds of thinking and maybe worse at others, that all that time spent online has already slightly rewired their brains. They also assume that the rewiring will advance along with the technology. There’s prehistoric precedent for that. Gary Small:

GARY SMALL: I would put forward that all the new technology will create a major milestone in brain evolution, just like the development of the handheld tool did many years ago.

BROOKE GLADSTONE: How did that change our brains?

GARY SMALL: It coincided with the growth of the prefrontal cortex, as well as coevolution of grammatical language and more complex social networks. So that was a major milestone, just that one minor invention. So I think that the future brain will be quite an extraordinary organ, and it will seamlessly interface with our external computer technology.

BROOKE GLADSTONE: Our future brain, freed from the gravitational drag of space or time, or even language, will inevitably evolve. And so must the definition of what makes us human, because it’s possible that someday we will carry cyberspace inside us and we will no longer know for sure where the human ends and the machine begins.