Sunstein, Cass R. Going to Extremes: How Like Minds Unite and Divide.

• Author: Li, Junpeng
• Position: Book review

Sunstein, Cass R. Going to Extremes: How Like Minds Unite and Divide. New York: Oxford University Press, 2009. 199 pages. Cloth, $21.95.

James Madison, the fourth president of the United States, once wrote eloquently, "The reason of man, like man himself, is timid and cautious when left alone, and acquires firmness and confidence in proportion to the number with which it is associated." (1) Madison's insight on association is elaborated and reformulated quite disturbingly in Cass Sunstein's Going to Extremes.

Known by more people as the administrator of the White House Office of Information and Regulatory Affairs, or President Barack Obama's "regulatory czar," Sunstein is a prominent legal scholar and behavioral scientist, and has written quite extensively, employing insights from psychology, sociology, and behavioral economics in his various writings. This slim volume sets out to answer a straightforward question: Why do average people gravitate toward extreme thoughts and behaviors? Sunstein's short answer is that extremism often happens when like-minded people interact. This message is surely not new to behavioral decision scientists, as they have conducted numerous laboratory experiments showing that people's ideas and beliefs often come from factors other than deliberation, but Sunstein excels in presenting his cases and synthesizing others' insights eloquently.

This book is full of historical cases and evidence from laboratory experiments. For example, in a small experiment conducted by Sunstein and his colleagues, approximately sixty Americans consisting of "liberals" and "conservatives" were enlisted and assigned to ten groups, five liberal and the other five conservative. These groups were then asked to deliberate on three controversial issues: same-sex marriage, affirmative action, and global warming. The result? Group members' opinions became more extreme and much less diverse internally, and the liberals and conservatives displayed wider rift (pp. 5-8). Sunstein also contrasts George W. Bush's presidency with that of Abraham Lincoln's. He describes Bush's presidency as an unhealthy "Team of Unrivals" in which internal dissent was discouraged. By contrast, Lincoln's presidency is described as a healthy "Team of Rivals" in which Lincoln and team members' inclinations were constantly challenged (pp. 29-30).

Sunstein's book is organized around some fascinating middle-range mechanisms, such as group polarization, rhetorical...