Deliberative trouble? Why groups go to extremes.

• Author: Sunstein, Cass R.

The differences of opinion, and the jarring of parties in [the legislative] department of the government ... often promote deliberation and circumspection, and serve to check excesses in the majority.

--Alexander Hamilton(1)

In everyday life the exchange of opinion with others checks our partiality and widens our perspective; we are made to see things from their standpoint and the limits of our vision are brought home to us.... The benefits from discussion lie in the fact that even representative legislators are limited in knowledge and the ability to reason. No one of them knows everything the others know, or can make all the same inferences that they can draw in concert. Discussion is a way of combining information and enlarging the range of arguments.

--John Rawls(2)

Each person can share what he or she knows with the others, making the whole at least equal to the sum of the parts. Unfortunately, this is often not what happens....

... As polarization gets underway, the group members become more reluctant to bring up items of information they have about the subject that might contradict the emerging group consensus. The result is a biased discussion in which the group has no opportunity to consider all the facts, because the members are not bringing them up.

....

... Each item they contributed would thus reinforce the march toward group consensus rather than add complications and fuel debate.

--Patricia Wallace(3)

1. INTRODUCTION

   Consider the following events:

   * Affirmative action is under attack in the state of Texas. A number of professors at a particular branch of the University of Texas are inclined to be supportive of affirmative action; they meet to exchange views and, if necessary, to plan further action. What are these professors likely to think, and to do, after they talk?

   * After a nationally publicized shooting at a high school, a group of people in the community, most of them tentatively in favor of greater gun control, come together to discuss the possibility of imposing new gun control measures. What, if anything, will happen to individual views as a result of this discussion?

   * A jury is deciding on an appropriate punitive damage award in a case of recklessly negligent behavior by a large company; the behavior resulted in a serious injury to a small child. Before deliberating as a group, individual jurors have chosen appropriate awards, leading to an average of $1.5 million and a median of $1 million. As a statistical generalization, how will the jury's ultimate award tend to compare to these figures?

   * A group of women is concerned about what they consider to be a mounting "tyranny of feminism." They believe that women should be able to make their own choices, but they also think that men and women are fundamentally different, and that their differences legitimately lead to different social roles. The group decides to meet every two weeks to focus on common concerns. Is it possible to say what its members are likely to think after a year?

   Every society contains innumerable deliberating groups. Church groups, political parties, women's organizations, juries, legislative bodies, regulatory commissions, multimember courts, faculties, student organizations, those participating in talk radio programs, Internet discussion groups, and others engage in deliberation. It is a simple social fact that sometimes people enter discussions with one view and leave with another, even on moral and political questions.(4) Emphasizing this fact, many recent observers have embraced the traditional American aspiration to "deliberative democracy," an ideal that is designed to combine popular responsiveness with a high degree of reflection and exchange among people with competing views.(5) But for the most part, the resulting literature has not been empirically informed.(6) It has not dealt much with the real-world consequences of deliberation, and with what generalizations hold in actual deliberative settings, with groups of different predispositions and compositions.

   The standard view of deliberation is that of Hamilton and Rawls, as quoted above. Group discussion is likely to lead to better outcomes, if only because competing views are stated and exchanged. Aristotle spoke in similar terms, suggesting that when diverse people

   all come together ... they may surpass--collectively and as a body, although not individually--the quality of the few best.... [W]hen there are many [who contribute to the process of deliberation], each has his share of goodness and practical wisdom.... [S]ome appreciate one part, some another, and all together appreciate all.(7) But an important empirical question is whether and under what circumstances it is really true that "some appreciate one part, some another, and all together appreciate all."

   My principal purpose in this Essay is to investigate a striking but largely neglected(8) statistical regularity--that of group polarization--and to relate this phenomenon to underlying questions about the role of deliberation in the "public sphere"(9) of a heterogeneous democracy. In brief, group polarization means that members of a deliberating group predictably move toward a more extreme point in the direction indicated by the members' predeliberation tendencies.(10) "[L]ike polarized molecules, group members become even more aligned in the direction they were already tending."(11) Thus, for example, members of the first deliberating group are likely to become more firmly committed to affirmative action; the second group will probably end up favoring gun control quite enthusiastically; the punitive damages jury will likely come up with an award higher than the median, perhaps higher than the average as well, and very possibly as high as or higher than that of the highest predeliberation award of any individual member; and the group of women concerned about feminism is likely to become very conservative indeed on gender issues. Notably, groups consisting of individuals with extremist tendencies are more likely to shift, and likely to shift more; the same is true for groups with some kind of salient shared identity (like Republicans, Democrats, and lawyers, but unlike jurors and experimental subjects).(12) When like-minded people are participating in "iterated polarization games"--when they meet regularly, without sustained exposure to competing views--extreme movements are all the more likely.

   Two principal mechanisms underlie group polarization. The first points to social influences on behavior and in particular to people's desire to maintain their reputation and their self-conception. The second emphasizes the limited "argument pools" within any group, and the directions in which those limited pools lead group members. An understanding of the two mechanisms provides many insights into deliberating bodies. Such an understanding illuminates a great deal, for example, about likely processes within multimember courts, juries, political parties, and legislatures--not to mention ethnic groups, extremist organizations, criminal conspiracies, student associations, faculties, institutions engaged in feuds or "turf battles," workplaces, and families. At the same time, these mechanisms raise serious questions about deliberation from the normative point of view.(13) If deliberation predictably pushes groups toward a more extreme point in the direction of their original tendency, whatever that tendency may be, is there any reason to think that deliberation is producing improvements?

   One of my largest purposes is to cast light on enclave deliberation as simultaneously a potential danger to social stability, a source of social fragmentation, and a safeguard against social injustice and unreasonableness.(14) Group polarization helps explain an old point, with clear constitutional resonances, to the effect that social homogeneity can be quite damaging to good deliberation.(15) When people are hearing echoes of their own voices, the consequence may be far more than support and reinforcement. An understanding of group polarization thus illuminates social practices designed to reduce the risks of deliberation limited to like-minded people. Consider the ban on single-party domination of independent regulatory agencies, the requirement of legislative bicameralism, and debates, within the United States and internationally, about the value of proportional or group representation. Group polarization is naturally taken as a reason for skepticism about enclave deliberation and for seeking to ensure deliberation among a wide group of diverse people.

   But there is a point more supportive of enclave deliberation: Participants in heterogeneous groups tend to give least weight to the views of low-status members(16)--in some times and places, women, African Americans, less-educated people. Hence enclave deliberation might be the only way to ensure that those views are developed and eventually heard. Without a place for enclave deliberation, citizens in the broader public sphere may move in certain directions, even extreme directions, precisely because opposing voices are not heard at all. The ambivalent lesson is that deliberating enclaves can be breeding grounds both for the development of unjustly suppressed views and for unjustified extremism, indeed fanaticism.

   This Essay is organized as follows. Part II discusses social influences on individual judgments, with particular reference to the phenomenon of social cascades. When a number of people have acted or spoken, observers who lack much private information are highly likely to follow their lead, a phenomenon that can drive participants in politics in unexpected and sometimes extreme directions. Part III offers a basic account of group polarization, with an elaboration of the underlying mechanisms of social influence and persuasive arguments. Parts IV, V, and VI deal with the implications of group polarization for democracy and law. Part IV is descriptive...