Groupthink versus The Wisdom of Crowds: The Social Epistemology of Deliberation and Dissent

Abstract Trust in the practice of rational deliberation is widespread and largely unquestioned. This paper uses recent work from business contexts to challenge the view that rational deliberation in a group improves decisions. Pressure to reach consensus can, in fact, lead to phenomena such as groupthink and to suppression of relevant data. Aggregation of individual decisions, rather than deliberation to a consensus, surprisingly, can produce better decisions than those of either group deliberation or individual expert judgment. I argue that dissent is epistemically valuable, not because of the discussion it can provoke (Mill's and Longino's view about the benefit of dissent), but because dissenting positions often are associated with particular data or insights that would be lost in consensus formation. Social epistemologists can usefully pay attention to various methods of aggregation of individual opinion for their effectiveness at realizing epistemic goals.