Damaging deliberations

Ideas from a meeting on Complex Networks, 2-6 July, Sardinia, Italy

In one of my recent New York Times columns, I explored the worrying polarization evident between the conservative and liberal bloggers in the US. I argued that it might well be the almost mechanical outcome of an amplifying feedback driven by simple psychological factors that influence how people form opinions and attitudes. First, the psychological phenomenon of “cognitive dissonance” tends to make us more comfortable with view that confirm rather than contradict our own. Second, people also have a strong tendency to adopt, even unconsciously, the attitudes of those with whom they interact. So the more conservative or liberal bloggers read the views in their own sphere, the more they're drawn into that sphere, express similar views, and end of living in an intellectual world of views that merely confirm their own.

That was speculation. But there's some exciting recent work that I think supports it -- some from network theorists here in Sardinia who are looking, rather abstractly, at the mathematics of opinion change within groups, and some from lawyers trying to address, in practical terms, how we might heal our polarization with greater deliberation. The lesson, I think, is that we had better be quite careful in what we do, or we could make the matter even worse.

Yesterday, physicist Renaud Lambiotte of the University of Liege in Belgium talked about his recent work (with physicists Marcel Ausloos and Janus Hoylst) in modeling the evolution of opinions. Their modeling suggests that two groups holding opposing views may quickly become reconciled, or remain at odds, and that what happens --and this is the important point -- can be very strongly influenced by the presence or absence of only a few social links between the groups. Here's the basic idea.

They supposed that individuals hold one of two opinions (it's not hard to think of some relevant issue), assigned randomly at the start. People in the model would then change their views, step by step, by a “majority rule” – each person would adopt (in the next time step) the opinion held by a majority of those with whom they were linked in the social network. The interesting thing to explore is how the structure of the network influences what ultimately happens.

Lambiotte and colleagues started by imagining two groups that were isolated from one another, or nearly isolated. Not surprisingly, perhaps, they found that people within each group quickly came to share one opinion. The groups came to a consensus, although the two groups were as likely to agree as disagree with each other. But the researchers then began adding social links between the groups, to see how this might change the outcome.

They found no change, at first, as the two groups continued to form opinions independently. But rather than a gradual increase in the way opinions “leak” from one group to the other as more connections are added, the researchers found a surprise when the number of links between the groups reached a precise threshold. Abruptly, the final opinions of the two groups were now always identical. Even a few extra links between groups were enough to “tip” their final opinions from a state of full polarization to full agreement.

This finding represents the social equivalent (in this simple model) of what physicists call a "phase transition", closely akin to the abrupt transformation of liquid water to ice. The interesting thing is that the change from one outcome to the other isn't gradual, but very rapid, and happens at some critical threshold of links between the groups. Near this boundary, a tiny alteration of the network structure can lead to drastic consequences.

Now this is quite abstract, but it may still be highly relevant to the real world. A number of studies have noted increasing polarization in recent years, not only in the web, but in geographical zones as well, with some parts of the US, for example, becoming more homogeneously conservative or liberal. Legal academics have been concerned with the consequences of this trend for our democratic discourse, and ability to come to collective decisions. What can we do?

Some legal theorists have suggested that one way to counter this trend would be to have special "deliberation days", during which people would come together in "town hall" meetings to discuss key issues. But some experiments carried out by Cass Sunstein and colleagues at the University of Chicago suggest that he outcome of such meetings can be counterproductive.

They had both liberals and conservatives from different cities in Colorado come together to discuss contemporary issues (gay marriage, the Iraq war, and so on) for a day, using surveys to gauge their views both before and after the deliberations. The liberals discussed issues among themselves, in one group, as did the conservatives, in another. What they found is that both groups became more extreme in their views during the discussions, and that the distance between the two groups became larger as a result. The conservatives became more conservative, and the liberals more liberal.

The lesson of these experiments is that those intermediary links between groups are absolutely essential to building overall consensus, and that, in their absence, we should expect an evolution toward greater extremism. But the more encouraging lesson from the network theory of Labiotte and colleagues is that only a few links between such groups can be remarkably successful in breaking down such polarization. Even if the situation seems bleak, and unchangeable, it may take only a few more contacts to seed a tremendous change.