We study experimentally the impact of group deliberation on individual distributional preferences. We elicit subjects' distributional preferences before and after group deliberation and estimate the relative weight of persuasion, social identity, and social comparison on the effect of deliberation. We find that 10 minutes of non-binding written group deliberation has a large effect on individual (private) distributional preferences. First, post-deliberation distributional preferences are more egalitarian than pre-deliberation preferences. Second, group polarization decreases after group deliberation. Finally, we find that social identity is the main but not unique driver of this effect. Persuasion and social comparison also impact individual preferences, particularly for subjects who are not monetarily affected by the distributive outcome. Our results bring novel insights for the elicitation of distributional preferences and the design of deliberative institutions.