The relevance of equal splits in ultimatum games

In this note we present a slightly altered version of the mini ultimatum game of G. E. Bolton and R. Zwick (1995, Games Econ. Behav.10, 95–121). More specifically, we replaced exactly equal splits by nearly equal splits either (slightly) favoring the proposer or the responder. Such a minor change should not matter if behavior was robust. We find, however, a significant change in behavior: Fair offers occur less often when equal splits are replaced by nearly equal splits.