Ultimatum bargaining with a group: Underestimating the importance of the decision rule

The three experiments presented here modified the standard ultimatum game by having a committee of five people either accept or reject offers made by one allocator. Although the decision rule the committee used to decide whether to accept or reject the offer had a large effect on the optimal allocation strategy, we hypothesized that allocators would have difficulty incorporating the implications of the committee's decision rule into their allocation decisions. Experiment 1 found subjects to be very insensitive to decision rule. In fact, decision rule had no effect on allocation decisions. Experiment 2 made the decision rule and its implications more obvious to subjects, but allocations still deviated from the strategies that would have maximized winnings. Experiment 3 provided convincing evidence that the reasons for these deviations from the maximizing strategy have to do with insensitivity to the implications of the group's decision rule and with the difficulty in thinking accurately about the cognitions of others. (C) 1997 Academic Press.