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Wednesday, December 11, 2019

Veil-of-ignorance reasoning favors the greater good

Karen Huang, Joshua D. Greene and Max Bazerman
PNAS first published November 12, 2019


The “veil of ignorance” is a moral reasoning device designed to promote impartial decision-making by denying decision-makers access to potentially biasing information about who will benefit most or least from the available options. Veil-of-ignorance reasoning was originally applied by philosophers and economists to foundational questions concerning the overall organization of society. Here we apply veil-of-ignorance reasoning in a more focused way to specific moral dilemmas, all of which involve a tension between the greater good and competing moral concerns. Across six experiments (N = 5,785), three pre-registered, we find that veil-of-ignorance reasoning favors the greater good. Participants first engaged in veil-of-ignorance reasoning about a specific dilemma, asking themselves what they would want if they did not know who among those affected they would be. Participants then responded to a more conventional version of the same dilemma with a moral judgment, a policy preference, or an economic choice. Participants who first engaged in veil-of-ignorance reasoning subsequently made more utilitarian choices in response to a classic philosophical dilemma, a medical dilemma, a real donation decision between a more vs. less effective charity, and a policy decision concerning the social dilemma of autonomous vehicles. These effects depend on the impartial thinking induced by veil-of-ignorance reasoning and cannot be explained by a simple anchoring account, probabilistic reasoning, or generic perspective-taking. These studies indicate that veil-of-ignorance reasoning may be a useful tool for decision-makers who wish to make more impartial and/or socially beneficial choices.


The philosopher John Rawls aimed to identify fair governing principles by imagining people choosing their principles from behind a “veil of ignorance,” without knowing their places in the social order. Across 7 experiments with over 6,000 participants, we show that veil-of-ignorance reasoning leads to choices that favor the greater good. Veil-of-ignorance reasoning makes people more likely to donate to a more effective charity and to favor saving more lives in a bioethical dilemma. It also addresses the social dilemma of autonomous vehicles (AVs), aligning abstract approval of utilitarian AVs (which minimize total harm) with support for a utilitarian AV policy. These studies indicate that veil-of-ignorance reasoning may be used to promote decision making that is more impartial and socially beneficial.