Mutual inclusivity improves decision-making by smoothing out choice's competitive edge.

Decision-making forms a central bottleneck to most of our tasks, one that people often experience as costly. To mitigate these costs, previous work has proposed adjusting one's threshold for deciding (e.g., satisficing) to avoid over-deliberating. Here, we test an alternative solution to these costs, one that targets the basis for most choice costs: the fact that choosing one option sacrifices others (mutual exclusivity). Across 4 studies (N = 385), we test whether this tension can be relieved by framing choices as inclusive (allowing more than one option from a set, similar to a buffet), and whether doing so improves decision-making and the experience thereof. We find that inclusivity makes choices more efficient, because of its unique impact on the level of competition between potential responses as participants accumulate information for each of their options (resulting in a more "race"-like decision process). We find that inclusivity also reduces the subjective costs associated with choice, making people feel less conflicted in conditions where it was hard to choose which good option to acquire or which bad option to get rid of. These inclusivity benefits were distinct from those achieved when trying to merely reduce deliberation (e.g., tightening one's deadline), which we show can in some cases lead to similar increases in efficiency but only carry the potential to diminish not improve the experience of choosing. This work collectively provides key mechanistic insights into the conditions under which decision making is most costly, and a novel approach aimed at mitigating those costs.