How to dissolve fixed-pie bias in negotiation? Social antecedents and the mediating effect of mental-model adjustment

Fixed-pie bias, defined as the erroneous belief that the other negotiation party's interest is directly opposite to one's own, has been a consistent hurdle that negotiators must overcome in their efforts to achieve optimal negotiation outcomes. In this study, we explore the underlying cognitive mechanism and the social antecedents of fixed-pie bias reduction in negotiation. Using data from a negotiation simulation with 256 participants, we found that mental-model adjustments made by negotiators could effectively decrease fixed-pie bias. More interestingly, we also found that negotiators were less likely to reduce fixed-pie bias when negotiating with an in-group member than with an out-group member but only under a high accountability condition. Finally, we found that mental-model adjustment mediated the effects of the aforementioned social antecedents (in-groupness and accountability) on reduced fixed-pie bias. We discuss the theoretical and practical implications of these findings.