Two experiments compared the Centipede game played either by 2 individuals or by 2 (3-person) groups. The 2 competitors alternate in deciding whether to take the larger portion of an increasing (or constant) pile of money, and as soon as one ''takes'' the game ends. Assuming that both sides are concerned only with maximizing their own payoffs (and that this is common knowledge), the game theoretic solution, derived by backward induction, is for the first mover to exit the game at the first decision node. Both experiments found that although neither individuals nor groups fully complied with this solution, groups did exit the game significantly earlier than individuals. The study of experimental games has uncovered many instances in which individuals deviate systematically from the game theoretic solution. This study is in accord with other recent experiments in suggesting that game theory may provide a better description of group behavior.

We report four repetitions of Falk and Kosfeld's (Am. Econ. Rev. 96(5): [1611][1612][1613][1614][1615][1616][1617][1618][1619][1620][1621][1622][1623][1624][1625][1626][1627][1628][1629][1630] 2006) low and medium control treatments with 476 subjects. Each repetition employs a sample drawn from a standard subject pool of students and demographics vary across samples. We largely confirm the existence of hidden costs of control but, contrary to the original study, hidden costs of control are usually not substantial enough to significantly undermine the effectiveness of economic incentives. Our subjects were asked, at the end of the experimental session, to complete a questionnaire in which they had to state their work motivation in hypothetical scenarios. Our questionnaires are identical to the ones administered in Falk and Kosfeld's (Am. Econ. Rev. 96(5):1611-1630, 2006) questionnaire study. In contrast to the game play data, our questionnaire data are similar to those of the original questionnaire study. In an attempt to solve this puzzle, we report an extension with 228 subjects where performance-contingent earnings are absent i.e. both principals and agents are paid : Experimental Economics ; 15 (2012), 2. -S. 323-340 https://dx.doi.org/10.1007 according to a flat participation fee. We observe that hidden costs significantly outweigh benefits of control under hypothetical incentives.

We show that experimental subjects tend to contribute more to the public good if they perceive the actions of the others as a source of positive externality rather than a source of negative externality. In our experiment partial contribution to the public good is the unique subgame perfect equilibrium for the repeated game. RésuméDans cet article, nous montrons que le degré de coopération de sujets placés dans un mécanisme de contribution volontaire est différent suivant que les choix des sujets induisent des externalités positives (contexte positif) ou des externalités négatives (contexte négatif). Les sujets participant au contexte positif ont un taux de sur-contribution supérieur au taux de sur-contribution des sujets participant au contexte négatif. Notre expérience se caractérise par une stratégie dominante d'investissement partiel dans le bien public.

International audienceThis article reports results of an experiment designed to analyze the link between risky decisions made by couples and risky decisions made separately by each spouse. We estimate both the spouses and the couples' degrees of risk aversion, we assess how the risk preferences of the two spouses aggregate when they make risky decisions, and we shed light on the dynamics of the decision process that takes place when couples make risky decisions. We find that, far from being fixed, the balance of power within the household is malleable. In most couples, men have, initially, more decision-making power than women but women who ultimately implement the joint decisions gain more and more power over the course of decision making

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