Date Published: November 14, 2018
Publisher: Public Library of Science
Author(s): Ciril Bosch-Rosa, Pablo Brañas-Garza.
This paper studies whether intentionality is more prevalent than fairness in social preferences. We do this by introducing a new three-player game in which the choices of neutral third-party arbiters are isolated from any monetary or strategic concerns. This allows us to study the normative preferences of subjects, and to compare the relative weight they give to intentions and inequality. The results show that arbiters are mainly concerned with inequality, while other’s (selfish) intentions seem to play a minor role in their preferences. This result is robust to a series of experimental designs, suggesting that the role of intentions in social preferences might be smaller than implied by the previous literature.
Social preferences are relevant in many research fields, from economics, philosophy  and conflict resolution , to anthropology  and evolutionary biology . Some authors even consider social preferences to be one of the main pillars of legal studies . A better understanding of social preferences is therefore not only relevant to refine models of fairness and cooperation, but can help understand many other fundamental questions about human behavior.
As subjects arrived to the lab, they were seated randomly in front of a terminal and the initial instructions were read aloud. In these instructions we announced that:
The experiment was run with a total of 234 undergraduates from both Universitat Pompeu Fabra (UPF) in Barcelona, and the University of California Santa Cruz (UCSC) in Santa Cruz, California (UCSC IRB approved this study as Exempt (category 2) as part of LEEPS Lab protocol HS1240 on August 26, 2008. All subjects provided written informed consent). Each session had 3 rounds and lasted on average 30 minutes. The mean earnings at UCSC were of $4.5 and at UPF of €4.35 plus a show-up fee ($5 and €3) (from now on, we will use the dollar sign to include both euros and dollars). The show-up fee was announced only at the end of the experiment, as we believe that while most subjects are aware of the rule of a “show-up fee” not announcing it until the end of the experiment adds pressure to the arbiters would their decisions result in a rejection. Subjects were recruited through the ORSEE systems of each university , and were required not to have any previous experience in bargaining games. Details on ordering and number of observations for each session can be found in Tables 2 and 3. Additionally, Supporting Information S1 Appendix shows that there are no significant ordering effects.
From conflict resolution to evolutionary biology, social preferences are an object of study in many different research areas. A complete understanding of how they operate should be a priority, yet the results we have on the relative importance of selfish intentions versus inequality aversion appear inconclusive; while [6, 8] claim that intentions are the main driver behind the actions of third parties,  show that subjects respond more to outcomes than to intentions.