Minimally acceptable altruism and the ultimatum game

I suppose that people react with anger when others show themselves not to be minimally altruistic. With heterogeneous agents, this can account for the experimental results of ultimatum and dictator games. Moreover, it can account for the surprisingly large fraction of individuals who offer an even split with parameter values that are more plausible than those that are required to explain outcomes in these experiments with the models of Levine [Levine, D.K., 1998. Modeling altruism and spitefulness in experiments. Review of Economic Dynamics 1, 593–622], Fehr and Schmidt [Fehr, E., Schmidt, K.M., 1999. A theory of fairness, competition and cooperation. Quarterly Journal of Economics 114, 817–868], Dickinson [Dickinson, D.L., 2000. Ultimatum decision making: a test of reciprocal kindness. Theory and Decision 48, 151–177] and Bolton and Ockenfels [Bolton, G.E., Ockenfels, A., 2000. ERC: a theory of equity, reciprocity, and competition. American Economic Review 90, 166–193].