Proceedings of the Annual Meeting of the Cognitive Science Society

We are constantly faced with the question of how to aggregate preferences, views, perspectives and values. This is a problem for groups attempting to accommodate individuals with differing needs and interests, as will be our focus. The problem of ``value aggregation'' therefore crops up in myriads of places across the social sciences---in rational decision theory, social choice models, and proposals for systems of democratic voting, for instance. These sub-disciplines have formalized proposals for how to deal with value aggregation, though, remarkably, no research has yet directly compared people's intuitions of two of the most obvious candidates for aggregation--taking the sum of all the values (the classic ``Utilitarian'' approach) and the product (a less well-known ``contractualist'' approach). In this paper, we systematically explore the proposals suggested by each algorithm, focusing on aggregating preferences across groups. We find that both humans and performant LLMs prefer a contractualist approach.