Behavioral bargaining theory: Equality bias, risk attitude, and reference-dependent utility

We develop a new theory, termed the behavioral bargaining theory (henceforth, BBT), that explains various observed behaviors in bargaining experiments in a unified manner. The key idea is to modify Nash’s (1950) model by endowing the players’ utility functions with a new concept, named entitlement, that represents the amount of money the player feels entitled to receive. We first apply BBT to explain the equality bias that is widely observed in the laboratory. We argue that our explanation of the bias in terms of entitlements is more easily interpretable than the extant explanation in terms of risk attitudes. Then, we demonstrate that BBT can also explain other behavioral patterns beyond the equality bias by suitably setting entitlements. Finally, we provide empirical support to BBT by using experimental data from Takeuchi et al. (2022), where entitlements of players can be inferred from the experimental design.