In 1995 the technology specialist Nicholas Negroponte predicted the emergence of "the Daily Me" -- a newspaper that you design personally, with each component carefully screened and chosen in advance. For many of us, Negroponte's prediction is coming true. As a result of the Internet, personalization is everywhere. If you want to read essays arguing that climate change is a fraud and a hoax, or that the American economy is about to collapse, the technology is available to allow you to do exactly that. If you are bored and upset by the topic of genocide, or by recent events in Iraq or Pakistan, you can avoid those subjects entirely. With just a few clicks, you can find dozens of Web sites that show you are quite right to like what you already like and think what you already think.
Actually you don't even need to create a Daily Me. With the Internet, it is increasingly easy for others to create one for you. If people know a little bit about you, they can discover, and tell you, what "people like you" tend to like -- and they can create a Daily Me, just for you, in a matter of seconds. If your reading habits suggest that you believe that climate change is a fraud, the process of "collaborative filtering" can be used to find a lot of other material that you are inclined to like. Every year filtering and niche marketing become more sophisticated and refined. Studies show that on Amazon, many purchasers can be divided into "red-state camps" and "blue-state camps," and those who are in one or another camp receive suitable recommendations, ensuring that people will have plenty of materials that cater to, and support, their predilections.
Of course self-sorting is nothing new. Long before the Internet, newspapers and magazines could often be defined in political terms, and many people would flock to those offering congenial points of view. But there is a big difference between a daily newspaper and a Daily Me, and the difference lies in a dramatic increase in the power to fence in and to fence out. Even if they have some kind of political identification, general-interest newspapers and magazines include materials that would not be included in any particular Daily Me; they expose people to topics and points of view that they do not choose in advance. But as a result of the Internet, we live increasingly in an era of enclaves and niches -- much of it voluntary, much of it produced by those who think they know, and often do know, what we're likely to like. This raises some obvious questions. If people are sorted into enclaves and niches, what will happen to their views? What are the eventual effects on democracy?
To answer these questions, let us put the Internet to one side for a moment and explore an experiment conducted in Colorado in 2005, designed to cast light on the consequences of self-sorting. About 60 Americans were brought together and assembled into a number of groups, each consisting of five or six people. Members of each group were asked to deliberate on three of the most controversial issues of the day: Should states allow same-sex couples to enter into civil unions? Should employers engage in affirmative action by giving a preference to members of traditionally disadvantaged groups? Should the United States sign an international treaty to combat global warming?
As the experiment was designed, the groups consisted of "liberal" and "conservative" enclaves -- the former from Boulder, the latter from Colorado Springs. It is widely known that Boulder tends to be liberal, and Colorado Springs tends to be conservative. Participants were screened to ensure that they generally conformed to those stereotypes. People were asked to state their opinions anonymously both before and after 15 minutes of group discussion. What was the effect of that discussion?
In almost every case, people held more-extreme positions after they spoke with like-minded others. Discussion made civil unions more popular among liberals and less popular among conservatives. Liberals favored an international treaty to control global warming before discussion; they favored it far more strongly after discussion. Conservatives were neutral on that treaty before discussion, but they strongly opposed it after discussion. Liberals, mildly favorable toward affirmative action before discussion, became strongly favorable toward affirmative action after discussion. Firmly negative about affirmative action before discussion, conservatives became fiercely negative about affirmative action after discussion.
The creation of enclaves of like-minded people had a second effect: It made both liberal groups and conservative groups significantly more homogeneous -- and thus squelched diversity. Before people started to talk, many groups displayed a fair amount of internal disagreement on the three issues. The disagreements were greatly reduced as a result of a mere 15-minute discussion. In their anonymous statements, group members showed far more consensus after discussion than before. The discussion greatly widened the rift between liberals and conservatives on all three issues.
The Internet makes it exceedingly easy for people to replicate the Colorado experiment online, whether or not that is what they are trying to do. Those who think that affirmative action is a good idea can, and often do, read reams of material that support their view; they can, and often do, exclude any and all material that argues the other way. Those who dislike carbon taxes can find plenty of arguments to that effect. Many liberals jump from one liberal blog to another, and many conservatives restrict their reading to points of view that they find congenial. In short, those who want to find support for what they already think, and to insulate themselves from disturbing topics and contrary points of view, can do that far more easily than they can if they skim through a decent newspaper or weekly newsmagazine.
A key consequence of this kind of self-sorting is what we might call enclave extremism. When people end up in enclaves of like-minded people, they usually move toward a more extreme point in the direction to which the group's members were originally inclined. Enclave extremism is a special case of the broader phenomenon of group polarization, which extends well beyond politics and occurs as groups adopt a more extreme version of whatever view is antecedently favored by their members.
Why do enclaves, on the Internet and elsewhere, produce political polarization? The first explanation emphasizes the role of information. Suppose that people who tend to oppose nuclear power are exposed to the views of those who agree with them. It stands to reason that such people will find a disproportionately large number of arguments against nuclear power -- and a disproportionately small number of arguments in favor of nuclear power. If people are paying attention to one another, the exchange of information should move people further in opposition to nuclear power. This very process was specifically observed in the Colorado experiment, and in our increasingly enclaved world, it is happening every minute of every day.
The second explanation, involving social comparison, begins with the reasonable suggestion that people want to be perceived favorably by other group members. Once they hear what others believe, they often adjust their positions in the direction of the dominant position. Suppose, for example, that people in an Internet discussion group tend to be sharply opposed to the idea of civil unions for same-sex couples, and that they also want to seem to be sharply opposed to such unions. If they are speaking with people who are also sharply opposed to these things, they are likely to shift in the direction of even sharper opposition as a result of learning what others think.
The final explanation is the most subtle, and probably the most important. The starting point here is that on many issues, most of us are really not sure what we think. Our lack of certainty inclines us toward the middle. Outside of enclaves, moderation is the usual path. Now imagine that people find themselves in enclaves in which they exclusively hear from others who think as they do. As a result, their confidence typically grows, and they become more extreme in their beliefs. Corroboration, in short, reduces tentativeness, and an increase in confidence produces extremism. Enclave extremism is particularly likely to occur on the Internet because people can so easily find niches of like-minded types -- and discover that their own tentative view is shared by others.
It would be foolish to say, from the mere fact of extreme movements, that people have moved in the wrong direction. After all, the more extreme tendency might be better rather than worse. Increased extremism, fed by discussions among like-minded people, has helped fuel many movements of great value -- including, for example, the civil-rights movement, the antislavery movement, the antigenocide movement, the attack on communism in Eastern Europe, and the movement for gender equality. A special advantage of Internet enclaves is that they promote the development of positions that would otherwise be invisible, silenced, or squelched in general debate. Even if enclave extremism is at work -- perhaps because enclave extremism is at work -- discussions among like-minded people can provide a wide range of social benefits, not least because they greatly enrich the social "argument pool." The Internet can be extremely valuable here.
But there is also a serious danger, which is that people will move to positions that lack merit but are predictable consequences of the particular circumstances of their self-sorting. And it is impossible to say whether those who sort themselves into enclaves of like-minded people will move in a direction that is desirable for society at large, or even for the members of each enclave. It is easy to think of examples to the contrary -- the rise of Nazism, terrorism, and cults of various sorts. There is a general risk that those who flock together, on the Internet or elsewhere, will end up both confident and wrong, simply because they have not been sufficiently exposed to counterarguments. They may even think of their fellow citizens as opponents or adversaries in some kind of "war."
The Internet makes it easy for people to create separate communities and niches, and in a free society, much can be said on behalf of both. They can make life a lot more fun; they can reduce loneliness and spur creativity. They can even promote democratic self-government, because enclaves are indispensable for incubating new ideas and perspectives that can strengthen public debate. But it is important to understand that countless editions of the Daily Me can also produce serious problems of mutual suspicion, unjustified rage, and social fragmentation -- and that these problems will result from the reliable logic of social interactions.
Cass R. Sunstein, a professor of law and political science at the University of Chicago, is author of Republic 2.0, published in October by Princeton University Press.
copyright 2007 The Chronicle of Higher Education