Working Paper: NBER ID: w13687
Authors: Edward L. Glaeser; Cass R. Sunstein
Abstract: When members of deliberating groups speak with one another, their predeliberation tendencies often become exacerbated as their views become more extreme. The resulting phenomenon -- group polarization -- has been observed in many settings, and it bears on the actions of juries, administrative tribunals, corporate boards, and other institutions. Polarization can result from rational Bayesian updating by group members, but in many contexts, this rational interpretation of polarization seems implausible. We argue that people are better seen as Credulous Bayesians, who insufficiently adjust for idiosyncratic features of particular environments and put excessive weight on the statements of others where there are 1) common sources of information; 2) highly unrepresentative group membership; 3) statements that are made to obtain approval; and 4) statements that are designed to manipulate. Credulous Bayesianism can produce extremism and significant blunders. We discuss the implications of Credulous Bayesianism for law and politics, including media policy and cognitive diversity on administrative agencies and courts.
Keywords: No keywords provided
JEL Codes: A1
Edges that are evidenced by causal inference methods are in orange, and the rest are in light blue.
| Cause | Effect |
|---|---|
| group deliberation (D70) | increased extremism in opinions (D72) |
| credulous bayesianism (C11) | systematic errors in belief updating (D83) |
| group size (C92) | likelihood of errors (C52) |
| credulous bayesianism (C11) | decline in decision-making accuracy (D91) |
| group polarization (C92) | extreme beliefs within groups (C92) |
| group size (C92) | decline in decision-making accuracy (D91) |