Group Polarization

The Case of the “Risky Shift”

The discovery of the risky shift phenomenon illustrates how an interesting discovery often leads researchers to hasty and erroneous conclusions, which ultimately get replaced with more accurate conclusions. While trying to understand the curious finding that group discussion enhanced risk taking, investigators discovered that discussion actually tends to strengthen whatever is the initially dominant point of view, whether risky or cautious.

A research literature of more than 300 studies comparing individual and group decision making began in 1961 with a surprising finding by James Stoner, then an MIT graduate student. For his master's thesis in industrial management, Stoner tested the commonly held belief that groups make more cautious decisions than do individuals. He invited people individually, and then in groups, to advise imagined characters how much risk to take. Here is an example of the kind of hypothetical scenario Stoner used, created for my own research:

Having marked their advice on a dozen such items, five or so individuals in Stoner's study would then discuss and reach agreement on each item. To everyone's amazement, given popular commentary about the conservatism of groups, the group decisions were usually riskier. During discussion, group members' opinions converged. Curiously, however, the point toward which they converged was usually a lower (riskier) number than their initial average.

Here was an interesting puzzle. The small risky shift effect was reliable, unexpected, and without any immediately obvious explanation. Dubbed the risky shift phenomenon, this finding inspired studies of risk taking by individuals and groups. These revealed that the risky shift occurs not only when a group decides by consensus—after a brief discussion, individuals, too, will alter their decisions. What is more, researchers successfully repeated Stoner's finding with people of varying ages and occupations in a dozen nations.

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