110 Yale L.J. 71 (2000)

In this Essay, I have discussed the phenomenon of group polarization and explored some of its implications for deliberation generally and deliberative democracy in particular. The central empirical finding is that group discussion is likely to shift judgments toward a more extreme point in the direction indicated by the median of predeliberation judgments. This is true if a group decision is required; if individuals are polled anonymously afterwards, they are likely to shift in precisely the same way.
 
The underlying mechanisms are twofold. The first involves people's desire to stand in a particular relation to the group, perhaps for reputational reasons, perhaps to maintain their self-conception. Shifts occur as people find that it is necessary to alter their positions in order to maintain their self-conception or their desired relation to the group. The second mechanism involves limited "argument pools," as members of groups with a certain initial tendency typically hear a large number of arguments in support of that tendency, and few arguments in the other direction. When arguments are skewed toward a particular point of view, group members will move in the direction of that point of view. In a finding of special importance to democratic theory, group polarization is heightened if members have a sense of shared identity. And in an equally important finding, group polarization is diminished, and depolarization may result, if members have a degree of flexibility in their views and groups consist of an equal number of people with opposing views.
 
In the abstract, and without knowing anything about the underlying substance, it is impossible to say whether group polarization is good or bad. But the mechanisms that underlie group polarization raise serious questions about the view that deliberation is likely to yield correct answers to social questions. Like-minded people engaged in discussion with one another may lead each other in the direction of error and falsehood, simply because of the limited argument pool and the operation of social influences. This point very much bears on deliberation within insulated groups and hence on emerging communications technologies, which allow a high degree of individual filtering; insulation and filtering can compound error. The point also bears on the design of deliberating courts, legislatures, and regulatory agencies. Above all, an understanding of group polarization helps explain why like-minded people, engaged in deliberation with one another, sometimes go to astonishing extremes and commit criminal or even violent acts.
 
This is the dark side of "enclave deliberation." But I have also emphasized that deliberation within protected enclaves can be highly desirable. Partly as a result of group polarization, enclave deliberation can produce positions that would otherwise fail to emerge and that emphatically deserve a public hearing. The case for enclave deliberation is strengthened by evidence that members of low-status groups are likely to be silent in, or silenced by, broader deliberating bodies. Group polarization within enclaves might even operate as a counterweight to this problem.
 
In the abstract, it is not possible to specify the appropriate mix of enclave deliberation and deliberation within larger publics. But an appreciation of group polarization helps show why a free society takes steps to protect deliberation within enclaves, to ensure that those inside enclaves hear alternative views, and to ensure as well that those outside of particular enclaves are exposed to what enclave members have to say. Above all, it is important to avoid a situation in which people are exposed to softer and louder echoes of their own voices.
 
In a heterogeneous society, this form of self-insulation can create serious deliberative trouble, in the form of mutual incomprehension or much worse. Legal arrangements will increase or reduce that trouble. I have outlined some approaches that might ensure that heterogeneity, far from being a source of social fragmentation, will operate as a creative force, helping to identify problems and even solutions that might otherwise escape notice.