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Group Polarization

By Charlotte Nickerson, published Dec 15, 2021


  • Group polarization is the tendency for groups to show a shift towards the extremes of decision-making when compared to decisions made by individuals.
  • When individual members of a group are already cautious in their attitude to a decision, they will show a shift toward an even more cautious attitude when they discuss this as part of a like-minded group.
  • When individuals are less cautious before a group discussion, they tend to show a shift towards more risky decisions when they are making a decision as part of a like-minded group. This type of group polarization is known as risky shift.
  • On average, groups will polarize (show accentuated judgments) toward the attitudes held before the group decision is reached.

Historical Background

Group polarization describes how members of a group adopt more extreme positions than the initial attitudes and actions of individual group members (Baumeister, 2007). This occurs because the collective involvement of groups amplifies individual attitudes and opinions, shifting them further in the direction of group norms (Colman, 2015).

The underpinnings of group polarization lie in Stoner’s (1961) now-discredited master's thesis on “risky shift,” which evolved into theories about choice shift. While group polarization necessitates choice shift, choice shift does not necessitate group polarization.

Group polarization can manifest in situations ranging from gambling behavior to social media, and can have positive, deleterious, or neutral effects.

Theoretical Approaches (Why Does It Happen?)

The first provocative study in social psychology to describe group polarization was Stoner’s (1961) master’s thesis describing the discovery of the “risky shift,” which concluded that groups generally behaved in a riskier way (taking bets with higher potential rewards but also lower probabilities) than individuals (Cartwright, 1971).

Although this finding in itself was eventually discredited (Friedkin, 1999), the phenomenon of choice shift continued to motivate research.

Traditional perspectives on social influence tended to emphasize accommodation and conformity but not necessarily the idea that groups had an “averaging effect” on individual’s perspectives (Friedkin, 1999).

Serge Moscovici, a Romanian-born French sociologist, and Marisa Zavalloni, an Italian-born Canadian social psychologist introduced the concept of group polarization.

The researchers studied a group of 140 male secondary school students in group discussions. The students, asked to discuss Charles De Gaulle and America tended to hold views more extremely favoring De Gaulle and disfavoring Americans after the discussion (Moscovici and Zavalloni, 1969).

Myers and Lamm (1978) describe the theoretical underpinnings of group polarization. Of early research in group polarization, several theories dominated:

  • social decision rules (ways that individual decisions can form into a group decision),
  • informational influence (where people learn as a result of hearing and giving cogent arguments considering the topic at hand),
  • social comparison effects,
  • responsibility dynamics (where having a large number of people in a group may make members feel less responsible for holding accountability for a given decision).


According to social network influence theory, these are the four main explanations of choice shift:

Persuasive Arguments Theory

Persuasive arguments theory posits that group polarization occurs because of the content of the arguments that happen during discussions.

This theory assumes that there is a group of arguments that can be applied to any issue and that the people participating in the discussion draw possible arguments from the pool of those that support their initial attitudes (Friedkin, 1999).

The group discussion's purpose, according to persuasive arguments theory, is to provide individuals with more complete information about the merits of alternative positions.

If the group of arguments that the group members draw in favor a more extreme position than the mean of the initial positions, then polarization is likely to occur (Friedkin, 1999).

The key idea of this hypothesis is that choice shift and group polarization depend on the action or implicit arguments for discussions resulting from group discussions or a rethinking of the issue.

However, this approach emphasizes that the simple visibility of group member attitudes is not sufficient for choice shifts.

Social Comparison Theory

Social comparison theory argues that people will enter a discussion espousing views less extreme than their true views because they fear being labeled deviant.

When group discussion reveals that other people have similar but more extreme attitudes in the group, this shifts the position of individuals from suppressing to exposing their true values or even taking on the more extreme positions of others (Baron and Roper, 1976; Friedkin, 1999).

All in all, this means that moderate positions are eroded by discussions and extreme positions encouraged (Friedkin, 1999).

This theory assumes that arguments on one extreme of the scale are more valued by the group than moderate or opposing views, as these arguments have higher visibility.

Self-Categorization Theory

Self-categorization theory explains that group polarization happens on the basis of a person’s conformity to an extreme norm or position of the group (Abrams, Wetherell, Cochrane, and Hogg, 1990).

This norm is not the average view but rather the prototypical position of the group. This prototypical position can be the group’s mean initial attitude, one of the group’s most extreme attitudes, or a view in-between these two, depending on how members of the group view their relationships with the out-groups.

Groups choose among visible individual positions and gravitate toward a normative position.

Proponents such as Turner and Reynolds (2011) of self-categorization theory believe that group members modify their attitudes to fit with a prototypical position to decrease the discrepancy between initial positions and implicit group norms (Friedkin, 1999).

If everyone accepts a norm prior to discussion, social influence Friedkin, 1999 predicts that there is no choice shift.

If there is no such preexisting norm, then self-categorization theory hypothesizes that the influence of a view depends on the interpersonal influences among group members; more powerful group members have greater influence (Friedkin, 1999).

Social Decision Scheme Theory

Finally, social decision scheme theory postulates that group decisions are a factor of the initial distribution of attitudes in the group and some decision scheme, otherwise known as a decision role that members use to obtain a decision (Davis, 1973).

Decision rules can encompass processes such as majority role, the mean of initial attitudes, the median of initial attitudes, the most extreme initial position and so fourth (Laughlin, 1980; Friedkin, 1999). In this view, choice shifts happen when these decision making rules produce a group decision differing from the mean initial attitude of group members.

Myers and Lamm emphasized that these motivating mechanisms for group polarization may not necessarily be mutually exclusive — they may amplify each other or operate during different phases of the decision making process (1978).

Myers and Lamm supported their motivating factors with a number of early studies. For example, supporting the responsibility dynamics hypothesis for group polarization, the researchers cited Wolosin et al. (1975).

Wolosin and his colleagues couples risks of shock with monetary rewards for the decision-makers and found that the more shocks (the riskier the decisions) of the group, the less responsibility any given group member felt for the groups’ decisions.

Group Polarization in Social Influence

Friedkin (1999) describes the interdependency between choice shift and group polarization. Choice shifts occur when, after a group’s interaction, the average attitude of group members differs from the member’s average initial attitude.

Meanwhile, group polarization happens when the choice shift is in the same direction as where the average initial attitude was inclined.

For example, if the average initial attitude of group members were slightly positive, then the average attitude of members after discussion would be more positive.

While group polarization always involves a choice shift, choice shift does not necessarily entail group polarization. Cartwright (1971) argued that “risky-shift” literature needed an analysis of the interpersonal influences that led to choice shifts.

In particular, he suggested that choice shifts could be produced by the process of interpersonal accommodation in itself. This means that no new process or separate group effect would be necessary to produce a group shift.

This was influenced by French (1956) and Harary’s (1959) formal theory of social power, which argues that a population’s power structure is formally related to its structure of influential communications.

This structure of influential communications is in turn related to its pattern and prevalence of interpersonal agreements (Friedkin, 2010). In social influence, this has the implication that choice shifts, such as group polarization are produced by individuals’ differences in susceptibilities and inequalities of interpersonal influence (Friedkin, 1999).

If individuals have different levels of interpersonal influence, then a choice shift will occur.


  • Book Club: Consider a book club, where individuals read books ahead of time and then discuss them with other group members. An individual may believe that the book was good, but far from the best book they have ever read, and this could also be the view of most other individuals in the book club.

    However, when the book club gathers and discusses the book, the group amplifies the good elements of the book, and members of the group leave with a more positive opinion of the book then they came in with.

    Group polarization has occurred here in that the group attitude has been enhanced and strengthened from thinking that the book was merely good to believing that it was excellent.

  • Disaster Relief Organization: Group polarization does not necessarily entail negative effects. Take the example of a disaster relief organization working with a government to determine how much aid to give to a region affected by a hurricane.

    The members of the organization may wish to allocate more aid than members of the government, for example.

    When these individuals have a discussion, the group’s normative value of giving aid becomes amplified, and as a result, both individuals from the organization and government groups may wish to allocate even more aid after the discussion.

  • Gambling Behavior: Researchers have used various gambling and betting tasks to investigate the effects of group interaction on risk taking. In one group of such studies, participants choose among different probabilities of winning, with lower probabilities having higher payoffs.

    Although the betting items differ in magnitude of stake, their expected value — the probable profit one would make if they carried out the gamble a large number of times — were the same (Lamm and Myers, 1978).

    Blascovich et al. conducted a series of studies on the game blackjack and found that, over a course of 20 trials, individuals who did not participate in groups did not change their risk-taking level, while groups tended to progressively take higher risks (Blascovich, Ginsburg, and Howe, 1975).

  • Social Media: Cass Sunstein’s (2001) influential work on “online informational cocoons' brought renewed interest to group polarization. Iandoll, Primmario, and Zollo (2021) conducted a systematic review of “dysfunctional” group polarization in the context of interaction enabled by social media.

    In general, the researchers found that social media contributes to increased polarization either by amplifying and escalating social processes that would also occur offline or in ways enabled by their design, making the platforms also prone to manipulation.

    Iandoll, Primmario, and Zollo argue that social media encourages group polarization in that it enables homophily — the tendency to engage with similar people, creating groups where certain beliefs become dominant — and discursive argumentation (Mercier and Sperber, 2011) — the use of reasoning by individuals and groups as a means of advancing their agenda.

    This manifests through four routes: (i) social antecedents (diverse viewpoints and external triggers such as partisan media); (ii) cognitive and social arguments (social comparison and social identity theory as well as persuasive argument theory); (iii) social effects (opinion radicalization and misinformation); and (iv) finally design affordances (such as content sharing, and the feeding and prioritization of information) (Iandoll, Primmario, and Zollo, 2021).

About the Author

Charlotte Nickerson is a member of the Class of 2024 at Harvard University. Coming from a research background in biology and archeology, Charlotte currently studies how digital and physical space shapes human beliefs, norms, and behaviors and how this can be used to create businesses with greater social impact.

How to reference this article:

Nickerson, C. (2021, Dec 15). Group Polarization. Simply Psychology.


Encyclopedia of Social Psychology. (2007). In. doi:10.4135/9781412956253

Abrams, D., Wetherell, M., Cochrane, S., Hogg, M. A., & Turner, J. C. (1990). Knowing what to think by knowing who you are: Self‐categorization and the nature of norm formation, conformity and group polarization. British journal of social psychology, 29(2), 97-119.

Baron, R. S., & Roper, G. (1976). Reaffirmation of social comparison views of choice shifts: Averaging and extremity effects in an autokinetic situation. Journal of Personality and Social Psychology, 33(5), 521.

Blascovich, J., Ginsburg, G. P., & Howe, R. C. (1975). Blackjack and the risky shift, II: Monetary stakes. Journal of Experimental Social Psychology, 11(3), 224-232.

Cartwright, D. (1971). Risk taking by individuals and groups: An assessment of research employing choice dilemmas. Journal of Personality and Social Psychology, 20(3), 361.

Colman, A. M. (2015). A dictionary of psychology: Oxford quick reference.

Davis, J. H. (1973). Group decision and social interaction: A theory of social decision schemes.

French Jr, J. R. (1956). A formal theory of social power. Psychological review, 63(3), 181.

Friedkin, N. (2010). A formal theory of social power. The Journal of Mathematical Sociology, 12, 103-126.

Friedkin, N. E. (1999). Choice shift and group polarization. American Sociological Review, 856-875.

Harary, F. (1959). Status and contrastatus. Sociometry, 22(1), 23-43.

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