Risky Shift

A risky shift is the tendency of groups to collectively make more extreme decisions than would any of its members individually. While cautious shifts sometimes occur, groups generally decide in favor of being more daring.

Theories/Speculation

According to Psyblog, a U.K.-based online psychology publication, there are three basic theories as to why group polarization takes place. While somewhat different, these are all rooted in one initial preference.

Persuasive Arguments

The rational arguments of others, especially when supporting a person's original position, tend to move that individual even farther in the direction of his own inclinations.

Conformity

People want to be viewed favorably by other group members. When a person hears what others believe, she may align her own position closer to that of the dominant belief system.

Differentiation

At times people defer to the type of decisions they believe are in the best interests of their group.

Escalation

Beyond Intractability.org suggests that as conflict escalates, communication and interaction are cut off and trust diminishes. This often leads to a breakdown in the decision-making process.

Source:

Beyond Intractability: Polarization

The American Institute for Avalanche Research and Education: The Risky Shift Phenomenon

Psyblog: Group Polarization: The Trend to Extreme Decisions

Resource:

Fragmentation and Cybercascades

Group Polarization and Educational Reform