Deliberation in group decisions: Polarization and like-mindedness

Deliberative decision-making is often proposed as a mechanism to mitigate polarization in democratic processes. However, empirical evidence remains mixed, with some studies suggesting that deliberation among like-minded individuals can drive preference shifts toward extremes. We use a three-round group dictator game to systematically examine how group composition influences deliberative outcomes. Our design allows us to compare deliberation within like-minded and mixed-minded groups while also manipulating the voting rule (median vs. unanimity) to assess its impact on decision-making. Contrary to expectations of polarization, we find that deliberation moderates preferences across all conditions. This effect is strongest for selfish participants in mixed-minded groups, but also like-minded selfish groups behave significantly less extreme than individuals. On the other hand, the moderating effect of deliberation does not persist when subjects revert back to individual decision-making. Regardless of the voting rule, groups tend to converge on unanimous decisions, suggesting norm-driven behavior in deliberative and participatory settings. Our findings contribute to ongoing debates on the role of group composition and decision rules in shaping collective outcomes in social dilemmas.