Proceedings of the Annual Meeting of the Cognitive Science Society

Even competitive activities require cooperation to agree on the rules. How do people navigate this tension, and what conditions help them reach agreement? We study rule negotiation in a collaborative game design task (N = 184) where dyads propose and vote on what game to play, crossing two factors: communication (chat available vs.~vote-only) and role uncertainty (whether players know which role they will occupy). We find communication increased agreement rates and role uncertainty had only a minimal impact on agreement. When players knew their role, they proposed games that subtly favored themselves, balancing self-interest against the need for acceptance. Chat content was largely coordinative rather than argumentative: players declared preferences and deferred rather than playing hardball. Our findings highlight how deliberation helps people coordinate on rules, even when they know which side they're on.