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  The Future of Free Speech — 6  

  Looking Back
  Vol II : issue 2

  Amit Chaudhuri
  Cass Sunstein
  Dibyendu Palit
  Vinay Lal
  Only in Print

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Cass Sunstein

Group Polarisation in General

The term “group polarisation” refers to something very simple: After deliberating with one another, people are likely to move toward a more extreme point in the direction to which they were previously inclined, as indicated by the median of their pre-deliberation judgements. With respect to the Internet, the implication is that groups of people, especially if they are like-minded, will end up thinking the same thing that they thought before — but in more extreme form.

Consider some examples of the basic phenomenon, which has been found in over a dozen nations.4 (a) A group of moderately pro-feminist women will become more strongly pro-feminist after discussion. (b) After discussion, citizens of France become more critical of the United States and its intentions with respect to economic aid. (c) After discussion, whites predisposed to show racial prejudice offer more negative responses to the question whether white racism is responsible for conditions faced by African-Americans in American cities. (d) After discussion, whites predisposed not to show racial prejudice offer more positive responses to the question stated above. As statistical regularities, it should follow, for example, that those moderately critical of an ongoing war effort will, after discussion, sharply oppose the war; that people tending to believe in the inferiority of a certain racial group will be entrenched in this belief as a result of discussion; that after discussion, people who tentatively think that the Second Amendment protects the right to own guns, and that government efforts at gun control are unconstitutional efforts to eliminate the public’s power of self-defence, will end up thinking that these propositions are undoubtedly true, and call for an immediate public response.

The phenomenon of group polarisation has conspicuous importance to the communications market, where groups with distinctive identities increasingly engage in within-group discussion. If the public is balkanised, and if different groups design their own preferred communications packages, the consequence will be further balkanisation, as group members move one another toward more extreme points in line with their initial tendencies. At the same time, different deliberating groups, each consisting of like-minded people, will be driven increasingly far apart, simply because most of their discussions are with one another. Extremist groups will often become more extreme; as we will soon see, the largest group polarisation typically occurs with individuals already inclined toward extremes.

Two Mechanisms

There have been two main explanations for group polarisation, both of which have been extensively investigated. Massive support has been found on behalf of both explanations.

Persuasive arguments. The first explanation emphasises the role of persuasive arguments. It is based on a common-sense intuition: any individual’s position on any issue is (fortunately!) a function of which arguments seem most convincing. If your position is going to move as a result of group discussion, it is likely to move in the direction of the most persuasive position defended within the group, taken as a collectivity. Of course — and this is the key point — a group whose members are already inclined in a certain direction will offer a disproportionately large number of arguments supporting that same direction, and a disproportionately small number of arguments going the other way. Such a discussion will therefore move individuals toward a more extreme point in line with their initial inclinations.

On this account, the central factor behind group polarisation is the existence of a limited argument pool, one that is skewed (speaking purely descriptively) in a particular direction. If a group of moderately feminist women becomes more feminist, a group moderately opposed to affirmative action more extremely so, and so forth, one reason is that the argument pool of any such group will contain a preponderance of arguments in the direction suggested. It is easy to see how this might happen with discussion groups on the Internet, and indeed with individuals not engaged in discussion but consulting only ideas to which they are antecedently inclined. The tendency of such discussion groups, and such consultations, will be to entrench preexisting positions.

Social comparison. The second mechanism, involving social comparison, begins with the claim that people want to be perceived favourably by other group members, and also to perceive themselves favourably. Once they hear what others believe, they adjust their positions in the direction of the dominant position. People may wish, for example, not to seem too enthusiastic, or too restrained, in their enthusiasm for affirmative action, feminism, or an increase in national defence; hence, their views may shift when they see what other people and in particular what other group members think.

The dynamic behind the social comparison explanation is that most people (of course, not all) want to take a position of a certain socially preferred sort. Within groups, no one can know what such a position would be until the positions of others are revealed. Thus individuals move their judgements to preserve their own image. A key claim here, supported by evidence, is that information alone — about the actual positions of others — without discussion, will produce a shift. The point has implications for exposure to ideas and claims even in the absence of a chance for interaction. If group polarisation will occur merely on the basis of exposure, it is likely to be a common phenomenon in a balkanised speech market.

Refinements and Shared Group Identity

Group polarisation is a highly general phenomenon. But in certain circumstances, it can be decreased, increased, or even eliminated. For present purposes, the most important refinement has to do with perceptions of identity and group membership. Group polarisation will significantly increase if people think of themselves, antecedently or otherwise, as part of a group having a shared identity and a degree of solidarity. If they think of themselves in this way, group polarisation is both more likely and more extreme. If, for example, a group of people in an Internet discussion group think of themselves as opponents of high taxes, or advocates of animal rights, their discussions are likely to move them in quite extreme directions. Similar movements should be expected for those who listen to a radio show known to be conservative, or a television programme dedicated to traditional religious values or to exposing white racism.

This should not be surprising. If ordinary findings of group polarisation are a product of social influences and limited argument pools, it stands to reason that when group members think of one another as similar along a salient dimension, or if some external factor (politics, geography, race, sex) unites them, group polarisation will be heightened.

p. 1 p. 2 p. 3 p. 4 p. 5 p. 6 p. 7 p. 8 p. 9 p.10 p. 11  


Cass Sunstein is Karl N. Llewellyn Distinguished Service Professor of Jurisprudence, University of Chicago. This article borrows from his forthcoming book Republic.com, to be published by Princeton University Press