We study social preferences in settings where someone who chooses on behalf of others knows how those individuals rank the available options but may lack cardinal information concerning those comparisons. Contrary to majoritarian principles, most people place more weight on preventing least preferred outcomes for others than on enabling most preferred outcomes. Ranks matter both intrinsically and because they provide a basis for inferring cardinal utility. Ordinal aggregation principles are stable across domains and countries with divergent political traditions. Designing attractive social choice mechanisms is challenging in practice partly because aggregation principles that make manipulation difficult yield outcomes people consider normatively unappealing.

Our recent working paper (Ambuehl, Ockenfels, and Stewart 2017) shows theoretically and experimentally that people with higher costs of information processing respond more to an increase in the incentive for a complex transaction, and decide to participate based on a worse understanding of its consequences. Here, we address the resulting tradeoff between the principle of informed consent and the principle of free contract. Respondents to our vignette study on oocyte donation overwhelmingly favor the former and support policies that require donors to thoroughly understand the transaction. This finding helps design markets that are not only efficient but also considered ethical.

Participation payments are used in many transactions about which people know little but can learn more: incentives for medical trial participation, signing bonuses for job applicants, or price rebates on consumer durables. Who opts into the transaction when given such incentives? We theoretically and experimentally identify a composition effect whereby incentives disproportionately increase participation among those for whom learning is harder. Moreover, these individuals use less information to decide whether to participate, which makes disappointment more likely. The learning-based composition effect is stronger in settings in which information acquisition is more difficult.

We examine methods for evaluating interventions designed to improve decision-making quality when people misunderstand the consequences of their choices. In an experiment involving financial education, conventional outcome metrics (financial literacy and directional behavioral responses) imply that two interventions are equally beneficial even though only one reduces the average severity of errors. We trace these failures to violations of the assumptions embedded in the conventional metrics. We propose a simple, intuitive, and broadly applicable outcome metric that properly differentiates between the interventions, and is robustly interpretable as a measure of welfare loss from misunderstanding consequences even when additional biases distort choices.

We study experimentally when, why, and how people intervene in others’ choices. Choice Architects (CAs) construct opportunity sets containing bundles of time-indexed payments for Choosers. CAs frequently prevent impatient choices despite opportunities to provide advice, believing Choosers benefit. They violate common behavioral welfare criteria by removing impatient options even when all payoffs are delayed. CAs intervene not by removing options they wish they could resist when choosing for themselves (mistakes-projective paternalism), but rather as if they seek to align others’ choices with their own aspirations (ideals-projective paternalism). Laboratory choices predict subjects’ support for actual paternalistic policies.

IRBs can disallow high incentives they deem coercive. A vignette study on MTurk concerning participation in medical trials shows that a substantial minority of subjects concurs. They think high incentives cause more regret, and that more people would be better off without the opportunity to participate. We model observers as judging the ethicality of incentives by partially using their own utility. The model predicts that payments are repugnant only to the extent that they affect the participation decision, and more so for larger transactions. Incentivizing poorer participants is more repugnant, and in-kind incentives are less repugnant than monetary incentives.

We investigate the impact of peer interaction on the quality of financial decision making in a laboratory experiment. Face-to-face communication with a randomly assigned peer significantly improves the quality of subsequent private decisions even though simple mimicry would have the opposite effect. We present evidence that the mechanism involves general conceptual learning (because the benefits of communication extend to previously unseen tasks), and that the most effective learning relationships are horizontal rather than vertical (because people with weak skills benefit most when their partners also have weak skills). The benefits of demonstrably effective financial education do not propagate to peers.