In social psychology, group polarization refers to the tendency for a group to make decisions that are more extreme than the initial inclination of its members. These more extreme decisions are towards greater risk if individuals' initial tendencies are to be risky and towards greater caution if individuals' initial tendencies are to be cautious. The phenomenon also holds that a group's attitude toward a situation may change in the sense that the individuals' initial attitudes have strengthened and intensified after group discussion, a phenomenon known as attitude polarization.
Group polarization is an important phenomenon in social psychology and is observable in many social contexts. For example, a group of women who hold moderately feminist views tend to demonstrate heightened pro-feminist beliefs following group discussion. Similarly, have shown that after deliberating together, mock jury members often decided on punitive damage awards that were either larger or smaller than the amount any individual juror had favored prior to deliberation. The studies indicated that when the jurors favored 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. Moreover, in recent years, the Internet and online social media have also presented opportunities to observe group polarization and compile new research. Psychologists have found that social media outlets such as Facebook and Twitter demonstrate that group polarization can occur even when a group is not physically together. As long as the group of individuals begins with the same fundamental opinion on the topic and a consistent dialogue is kept going, group polarization can occur.
Research has suggested that well-established groups suffer less from polarization, as do groups discussing problems that are well known to them. However, in situations where groups are somewhat newly formed and tasks are new, group polarization can demonstrate a more profound influence on the decision-making.
Attitude polarization, also known as belief polarization and polarization effect, is a phenomenon in which a disagreement becomes more extreme as the different parties consider evidence on the issue. It is one of the effects of confirmation bias: the tendency of people to search for and interpret evidence selectively, to reinforce their current beliefs or attitudes. When people encounter ambiguous evidence, this bias can potentially result in each of them interpreting it as in support of their existing attitudes, widening rather than narrowing the disagreement between them.