is the tendency of people to make decisions that are more extreme when they are in a group as opposed to a decision made alone or independently.
Study of this effect has shown that after participating in a discussion group, members tend to advocate more extreme positions and call for riskier courses of action than individuals who did not participate in any such discussion. This phenomenon was originally coined risky shift
but was found to apply to more than risk, so the replacement term choice shift
has been suggested.
In addition, attitudes such as racial and sexual prejudice tend to be reduced (for already low-prejudice individuals) and inflated (for already high-prejudice individuals) after group discussion.
Group polarization has been used to explain the decision-making of a jury, particularly when considering punitive damages in a civil trial. Studies have shown that after deliberating together, mock jury members often decided on punitive damage awards that were larger or smaller than the amount any individual juror had favoured prior to deliberation. The studies indicated that when the jurors favoured a relatively low award, discussion would lead to an even more lenient result, while if the jury was inclined to impose a stiff penalty, discussion would make it even harsher.
Developments in the study of group polarization
The study of group polarization began with an unpublished 1961 Master’s thesis by MIT student James Stoner, who observed the so-called "risky shift", meaning that a group’s decisions are riskier than the average of the individual decisions of members before the group met. The discovery of the risky shift was considered surprising and counter-intuitive, especially since earlier work in the 1920s and 1930s by Allport and other researchers suggested that individuals made more extreme decisions than did groups, leading to the expectation that groups would make decisions that would conform to the average risk level of its members. The seemingly counter-intuitive findings of Stoner led to a flurry of research around the risky shift, which was originally thought to be a special case exception to the standard decision-making practice. By the late 1960s, however, it had become clear that the risky shift was just one type of many attitudes that became more extreme in groups, leading Moscovici and Zavalloni to term the overall phenomenon "group polarization".
Thus began a decade-long period of examination of the applicability of group polarization to a number of fields, ranging from political attitudes to religion, in both lab and field settings. Basic studies of group polarization tapered off, but research on the topic continued. Group polarization was well-established, but remained non-obvious and puzzling because its mechanisms were not understood.
Mechanisms of polarization
Almost as soon as the phenomenon of group polarization was discovered, a variety of hypotheses was suggested for the mechanisms for its action. These explanations were gradually winnowed down and grouped together until two primary mechanisms remained, social comparison
and influence. Social comparison approaches, sometimes called interpersonal comparison, were based on social psychological views of self-perception and the drive of individuals to appear socially desirable . The second major mechanism is informational influence, which is also sometimes referred to as persuasive argument theory
, or PAT. PAT holds that individual choices are determined by individuals weighing remembered pro and con arguments
. These arguments are then applied to possible choices, and the most positive is selected. As a mechanism for polarization, group discussion shifts the weight of evidence as each individual exposes their pro and con arguments, giving each other new arguments and increasing the stock of pro arguments in favor of the group tendency, and con arguments against the group tendency. The persuasiveness of an argument depends on two factors – originality and its validity. According to PAT, a valid argument would hold more persuasive weight than a non-valid one. Originality has come to be understood in terms of the novelty of an argument. A more novel argument would increase the likelihood that it is an addition to the other group members’ pool of pro and con arguments, rather than a simple repetition.
In the 1970s, significant arguments occurred over whether persuasive argumentation alone accounted for group polarization. Daniel Isenberg’s 1986 meta-analysis of the data gathered by both the persuasive argument and social comparison camps succeeded, in large part, in answering the questions about predominant mechanisms. Isenberg concluded that there was substantial evidence that both effects were operating simultaneously, and that PAT operated when social comparison did not, and vice-versa. Isenberg did discover that PAT did seem to have a significantly stronger effect, however.
Group polarization in online discussions
Group polarization has also been found to occur with online (computer-mediated) discussions e.g. (Sia et al., 2002). In particular, research has found that group discussions conducted when discussants are in a distributed (cannot see one another) or anonymous (cannot identify one another) environment, can lead to even higher levels of group polarization compared to traditional meetings. This is attributed to the greater numbers of novel arguments generated (due to PAT) and higher incidence of one-upmanship behaviours (due to social comparison).
Incestuous amplification in the military
Within Pentagon circles "incestuous amplification" refers to positive reinforcement of one's own OODA loop
that may contribute to group polarization. It was used to describe how officers and men in the army can form very different analysis of the same situation because officers and men have different perspectives of the same problem, and how a prevailing view can become established wisdom by mere repetition.
"Incestuous amplification" is also the term used by writer John Stauber who with Sheldon Rampton has written the book The Best War Ever to describe the justification and conduct of the Iraq War immediately before and since 2003.
The risky shift
is the tendency for decisions taken by a group after discussion to display more experimentation, be less conservative and be more risky than those made by individuals acting alone prior to any discussion. In group conditions, people with relatively moderate viewpoints tend to assume that their groupmates hold more extreme views, and to alter their own views in compensation--a phenomenon known as groupthink
. This can occur simultaneously and in isolation: all
group members might adjust their views to a more conservative or liberal position, thus leading to a "consensus" that is totally false. The risky shift occurs when the group collectively agrees on a course of action that is likewise more extreme than they would have made if asked individually.
In 1970, Myers and Bishop demonstrated this effect by arranging students into groups to discuss issues of race. Groups of prejudiced students were found to be become even more prejudiced, while unprejudiced students became even more unprejudiced.
Today, the phenomenon is typically known by the more general name "Group polarization." The earliest experiments predominantly selected topics for which participants turned out to move towards riskier decisions, so the name "risky shift" was accurate. However, depending on the initial tendencies of group members, "cautious shift" outcomes are also possible. It is more accurate to say that following discussion, a group's actions will be a more extreme version of each individual's preferred action.
Risky shift or the more generalized tendency for groups to adjust their views in light of social context has profound impact on juries, who often decide the severity of punishment in light of the strength of the evidence they are presented.
- Moscovici, S., & Zavalloni, M. (1969). The group as a polarizer of attitudes. Journal of Personality and Social Psychology 12, 125-135
- Bray, R. M., & Noble, A. M. (1978). Authoritarianism and decisions of mock juries: Evidence of jury bias and group polarization. Journal of Personality and Social Psychology, 36, 1424-1430.
- MacCoun, R. J.; Kerr, N. L. (1988). Asymmetric influence in mock jury deliberation: Jurors' bias for leniency. Journal of Personality and Social Psychology, 54, 21-33.
- Sia, C. L., Tan, B. C. Y. and Wei, K. K. (2002). Group Polarization and Computer-Mediated Communication: Effects of Communication Cues, Social Presence, and Anonymity. Information Systems Research, 13, 1, 70-90.