“When Are N Heads Better (or Worse) Than One?”

A great deal of research in social and cognitive psychology has been devoted to demonstrating what is probably an uncontroversial proposition—that human judgment is imperfect. What makes this work interesting and useful is that such imperfections often constitute more than random fluctuations around “rational,” prescribed, or ideal judgments. Rather, humans consistently exhibit systematic biases in their judgments. Such judgmental biases are not only of theoretical interest; they also can have serious consequences (cf. Dawes, 1988; Thaler, 1985) and identifying means of controlling them is an important challenge.