When do groups make wise decisions? When do they may foolish decisions? What methods can help groups make wiser decisions? Cass Sunstein and Reid Hastie explore these questions in this helpful book. Part one examines several systemic mechanisms that cause groups to fail. Part two describes approaches that help groups avoid these errors.

During deliberations, group pressures may cause members to agree on a falsehood rather than the truth. Incorrect information may cascade through the group and preempt sharing of important contradictory information known to individuals in the group. Similarly, social pressure to agree with the forming consensus may become more powerful than incentives to share individually held information that is different and important. As a result groups can amplify rather than correct errors, incorrect information that gets early support from the group can cascade through the group, groups can reinforce biases held by individual members and concentrate these views to form a group polarization, and groups can focus only on shared information—what everybody already knows —and suppress expression of unshared information. Despite the value of teamwork, a confident, cohesive, but error-prone group is nothing to celebrate. Group deliberation can produce both great confidence and grave error. As a result, groups are even more likely than individuals to escalate their commitment to a course of action that is failing.

The authors make an important distinction between statistical groups—those whose members are acting independently—and deliberating groups—where each member is influencing others in the group. Because statistical groups are not prone to cascades and group polarization, they often make wiser decisions than deliberating groups. Misfits make deliberating groups uncomfortable, but wise groups take steps to protect these skeptics.

Fortunately, part two of the book provides specific techniques for structuring group decisions to increase the likelihood of a wise outcome.

Group leaders must make clear that hearing the truth is more important than an appearance of group unity. Surfacing bad news, minority opinions, contrary information, difficult questions, and inconvenient truths are all essential to wise decision making. “Wise leaders embrace a particular idea of what it means to be a team player: not to agree with the majority’s current view, but to add valuable information.” Unrealistic optimism early in the deliberations suppresses contrary but essential information; the time for optimism is after the decision has been made.

The authors describe eight approaches to leading wiser groups: 1) inquisitive and self-silencing leaders, 2) encouraging critical thinking while discouraging happy talk, 3) rewarding group success over individual contribution, 4) assigning distinct roles to individuals in the group, 5) changing perspective, 6) requiring devil’s advocates 7) forming red teams that are responsible for challenging or even defeating the group, and 8) the Delphi method.
When seeking a solution, it is important to separate the divergent thinking stages—identifying alternatives and potential solutions—from the convergent stages where the final solution is selected from among several alternatives. These tasks require very different thinking styles and work best when focused on separately.

Cost-benefit analysis and reliance on data provide valuable checks on both individual and group errors. Choose experts based on their proven ability to make winning bets on the future, rather than their popularity, charm, and storytelling skills. Combine the forecasts of several experts whenever possible. Carefully designed tournaments and prediction markets can be particularly effective in obtaining a wise outcome from many of participants.

Finally, a combination of traits called “Factor-C” reliably predicts team players who can come to a wise decision. These people rely on their high general IQ, exceptional emotional intelligence, and feminine sensitivities to bring forward the best in the groups they are part of.

The arguments throughout the book are well reasoned and clearly presented, relevant evidence supports and illustrates each claim, the book is well written and a pleasure to read. Practicing these group skills can help us bring wisdom to life. Certainly our democracy, business teams, organizations, and other groups can benefit from the observations and advice in this book. ( )