“Irving Janis’ Groupthink and the Sanhedrin of Ancient Israel” by Eliezer Schnall, a psychologist at Yeshiva University, and his student, Michael Greenberg. Presented at the American Psychological Association’s Annual Convention in Washington on Aug. 7.

The Argument: One of the most influential theories in the behavioral sciences in recent decades is “groupthink.” Developed by the psychologist Irving Janis in the early 1970s, the groupthink theory describes how a tight-knit, smart and well-informed group can suppress dissent and make disastrous decisions because of the pressure to agree. As examples, Janis used the failure to anticipate the Japanese attack on Pearl Harbor in 1941, the decision to invade Cuba in 1961 at the Bay of Pigs, and the American escalation of the Vietnam War in the mid-60s. Mr. Schnall argues that decision-making entities in the ancient world may have been aware of the danger of conformist thinking because they developed customs that are remarkably similar to Janis’s recommended preventatives. He examines, in particular, the practices of the Sanhedrin, the judicial and legislative body of ancient Israel.



The Evidence: To prevent leaders from favoring their own ideas and discouraging dissent leadership in the Sanhedrin was shared, ensuring that different viewpoints were heard. Junior members always spoke before senior ones to prevent them from tailoring their opinions to suit their superiors. Mr. Schnall notes that the Sanhedrin also adopted specific guidelines that mandated a review of all the evidence and information, as Janis suggested. To ensure that the group did not become too insular, members were required to consult outside experts. “Any scholar who heard of a Sanhedrin ruling that he believed erroneous was required to travel to Jerusalem and present his argument to the court,” Mr. Schnall writes, and “disciples watched court proceedings and were generally allowed to volunteer their opinions.” Just as Janis recommended postponing a final decision to allow for “second-chance meetings” outside of the normal venue, the Sanhedrin required that in certain instances, a final verdict be postponed a day after agreement was reached. In capital cases, the Sandehrin went so far as to acquit a defendant if there was a unanimous guilty verdict from its 70 members. The absence of dissension was perceived as evidence that group conformity was operating. Mr. Schnall writes that the Sanhedrin’s procedures highlight “practical ways that Janis’s ideas and prescriptions may be implemented by modern day managers and organizational bodies.”

What do you think? Is a unanimous decision a sign of a slam dunk or overwhelming groupthink?

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