Journal ArticleA new method for quantitatively documenting concerns for economic fairness has the potential for identifying variation in prosociality within and across societies. Multiple dictator games conducted in two small-scale societies presented decision makers with a choice between an equitable and an inequitable payoff distribution. The games varied in terms of the type of inequality the decision maker faced and the cost to the decision maker of eliminating inequality. A novel set of statistical models directly links experimental results and player heterogeneity with the formal theory of inequality aversion. The experimental method can be generalized to allow maximum flexibility in data analysis