Sharing the surplus and proportional values

Theory and Decision - We introduce a family of proportional surplus division values for TU-games. Each value first assigns to each player a compromise between her stand-alone worth and the average...     

Sanctioning as a social norm: Expectations of non-strategic sanctioning in a public goods game experiment

Sanctioning increases cooperation in public goods games, but not indiscriminately under all conditions and in all societies, and the mechanisms by which sanctioning exercises its impact on behavior are yet to be studied in detail. We show experimentally that in the presence of sanctioning, our experimental subjects adjust their behavior in order to avoid being a free rider. They do this not only in the STANDARD sanctions treatment, where they directly experience any sanctions assigned to them, but also in our main treatment, the SECRET sanctions treatment, where no information on sanctions received is available until the end of the experiment. We observe no such free riding avoidance in the treatment without sanctioning. The mere knowledge that sanctions might be assigned increases cooperation among the members of our subject pool; subjects expect that non-strategic sanctioning occurs against the free riders. Moreover, these expectations are correct as we observe a similar pattern and extent of sanctioning in both treatments. We propose that sanctioning in itself is a social norm and may be culturally dependent, as suggested in the literature.     

Contest and scramble competitions in two bruchid species,Callosobruchus analis andC. Phaseoli (Coleoptera: Bruchidae)

Summary We performed multiple-generation competition experiments betweenCallosobruchus analis andC. phaseoli with different bean sizes. In each system, we supplied 5 g of mung beans (Vigna radiata) every 10 days. We examined three types of bean conditions: 5 g of large beans, 5 g of small beans, and a mixture of 2.5 g of large and small beans. In small bean condition,C. analis dominatedC. phaseoli in all three replicates andC. phaseoli was extinct by the 260th day. On the contrary,C. phaseoli overcameC. analis within 250 days in large beans in all three replicates. In mixed beans condition the two bruchid species coexisted more than 500 days in two out of the three replicates. Even in the exceptional case, both species coexisted for 460 days. These results were examined in the light of the predictions from short-term larval competition experiments and a game theoretical model by Smith and Lessells (1985). The density and frequency dependent results during larval competition inside a bean was concluded to be a main factor to produce the above long-term competition results.     

Redistribution to the less productive: parallel characterizations of the egalitarian Shapley and consensus values

Theory and Decision - In cooperative game theory with transferable utilities (TU games), there are two well-established ways of redistributing Shapley value payoffs: using egalitarian Shapley...     

Reconciling marginalism with egalitarianism: consistency, monotonicity, and implementation of egalitarian Shapley values

One of the main issues in economic allocation problems is the trade-off between marginalism and egalitarianism. In the context of cooperative games this trade-off can be framed as one of choosing to allocate according to the Shapley value or the equal division solution. In this paper we provide three different characterizations of egalitarian Shapley values being convex combinations of the Shapley value and the equal division solution. First, from the perspective of a variable player set, we show that all these solutions satisfy the same reduced game consistency. Second, on a fixed player set, we characterize this class of solutions using monotonicity properties. Finally, towards a strategic foundation, we provide a non-cooperative implementation for these solutions which only differ in the probability of breakdown at a certain stage of the game. These characterizations discover fundamental differences as well as intriguing connections between marginalism and egalitarianism.     

Correction to: Redistribution to the less productive: parallel characterizations of the egalitarian Shapley and consensus values

Theory and Decision - In sub-Sect. 3.3, the terms “one-person” and “(n-1)-person” were incorrectly updated by mistake during the correction stage in the online...     

Axiomatizations of a Class of Equal Surplus Sharing Solutions for TU-Games

A situation, in which a finite set of players can obtain certain payoffs by cooperation can be described by a cooperative game with transferable utility, or simply a TU-game. A (point-valued) solution for TU-games assigns a payoff distribution to every TU-game. In this article we discuss a class of equal surplus sharing solutions consisting of all convex combinations of the CIS-value, the ENSC-value and the equal division solution. We provide several characterizations of this class of solutions on variable and fixed player set. Specifications of several properties characterize specific solutions in this class.     

Contest and scramble competitions inCallosobruchus maculatus (Coleoptera: Bruchidae) II. Larval competition and interference mechanisms

Summary Competition between contest and scramble strategists was examined using two strains ofCallosobruchus maculatus, the contest strain (iQ) and the scramble strain (tQ). The direct larval interference experiment within each strain showed that the contest strain performed strong direct interference throughout its larval stage against the conspecific opponent(s). The scramble strain also performed its interference, but only during the 3rd and the 4th larval stages. The inter-strain larval competition experiments inside a large and small mung bean (Vigna radiata) showed that the contest strain was, in general, superior to the scramble strain in competition, but the competition results were density- and frequency-dependent. In the large beans, the proportion of adult emergence of the contest strain increased with the increase of its own initial density but decreased as the initial density of the scramble strain increased. The shape of the proportion of adult emergence became nonlinear in the small beans. The cause of the complexity of inter-strain competition results was discussed in the light of the difference in larval interference ability between the two strains.