This is the author’s version of a work that was accepted for publication in Games and Economic Behavior . Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Games and Economic Behavior 64 (2008). DOI http://dx.doi.org/10.1016/j.geb.2007.10.009In experimental games, we observe the following phenomena: (1) many subjects cooperate contrary to their material interest, (2) they cooperate in a reciprocal manner, (3) subjects often punish those others who behave unkindly, and (4) previous history usually influences subjects’ choices. We propose a simple game-theoretical model to account for these and other experimental phenomena, and compare it with other models of social preferences and reciprocity.Ffinancial support from the Spanish Ministry of Education and Science

A recent experimental literature shows that truth-telling is not always motivated by pecuniary motives, and several alternative motivations have been proposed. However, their relative importance in any given context is still not totally clear. This paper investigates the relevance of pure lie aversion, that is, a dislike for lies independent of their consequences. We propose a very simple design where other motives considered in the literature predict zero truth-telling, whereas pure lie aversion predicts a non-zero rate. Thus we interpret the finding that more than a third of the subjects tell the truth as evidence for pure lie aversion. Our design also prevents confounds with another motivation (a desire to act as others expect us to act) not frequently considered but consistent with much existing evidence. We also observe that subjects who tell the truth are more likely to believe that others will tell the truth as well.

This article experimentally studies punishment from unaffected third parties in ten different games. The authors show that third-party punishment exhibits several features that are arguably undesirable. First, third parties punish strongly a decider if she chooses a socially efficient or a Pareto efficient allocation and becomes the richest party as a result. Interestingly, this form of punishment is especially pronounced in women and more left-wing participants. Second, third parties punish strongly a decider if she chooses an equitable allocation and becomes the richest party as a result. Finally, third parties considerably punish passive parties who make no choice, especially if the latter are richer than the third party. Implications of these findings for social theory are discussed.