Suchergebnisse

Social structure affects the likelihood of group conflicts, although it has been disregarded by previous explanations. This study extends the intergroup public goods game model and integrates the influence of structural embeddedness and social incentives in the analysis of harmful group conflict. The integrated model explains why intergroup conflicts are often promoted by segregation and describes conditions under which this effect does not occur. The model predicts that a relationship between segregation and the likelihood of conflict can be characterized by an S-shape function. The segregation effect is stronger if local selective incentives are relatively important compared to confirmation from neighbors. Results show that under certain structural conditions, rational individuals are more likely to be trapped in harmful conflict than less rational actors, and rigid assumptions about individual rationality strengthen the effect of clustering on intergroup conflict.

Direct and indirect reciprocity are good candidates to explain the fundamental problem of evolution of cooperation. We explore the conditions under which different types of reciprocity gain dominance and their performances in sustaining cooperation in the PD played on simple networks. We confirm that direct reciprocity gains dominance over indirect reciprocity strategies also in larger populations, as long as it has no memory constraints. In the absence of direct reciprocity, or when its memory is flawed, different forms of indirect reciprocity strategies are able to dominate and to support cooperation. We show that indirect reciprocity relying on social capital inherent in closed triads is the best competitor among them, outperforming indirect reciprocity that uses information from any source. Results hold in a wide range of conditions with different evolutionary update rules, extent of evolutionary pressure, initial conditions, population size, and density. ; Direct and indirect reciprocity are good candidates to explain the fundamental problem of evolution of cooperation. We explore the conditions under which different types of reciprocity gain dominance and their performances in sustaining cooperation in the PD played on simple networks. We confirm that direct reciprocity gains dominance over indirect reciprocity strategies also in larger populations, as long as it has no memory constraints. In the absence of direct reciprocity, or when its memory is flawed, different forms of indirect reciprocity strategies are able to dominate and to support cooperation. We show that indirect reciprocity relying on social capital inherent in closed triads is the best competitor among them, outperforming indirect reciprocity that uses information from any source. Results hold in a wide range of conditions with different evolutionary update rules, extent of evolutionary pressure, initial conditions, population size, and density.

A kamaszok körében tapasztalható intenzív státuszverseny egyik gyakori velejárója a pletykálkodás, amit a fiatalok gyakran használnak eszközként a csoporton belüli magasabb státusz elérésére. Ha valakiről sok negatív pletyka terjed, az előbb vagy utóbb veszít megbecsültségéből. Az alacsony megbecsültséggel rendelkező kamaszokról továbbá egyre több negatív pletyka terjedhet el. Ugyanakkor a gyakori pletykálás is vezethet alacsonyabb megbecsültséghez. Ezeknek a lehetséges folyamatoknak az elemzésére egy magyarországi középiskolai panel adatfelvétel (7 iskola, 40 osztály, NT1=1313) első három hullámának kapcsolathálózati adatait használtuk fel. A pletyka- és a reputációs hálózatok leíró statisztikai és korrelációs elemzése mellett hét gimnáziumi osztály esetében sztochasztikus aktororientált modellek segítségével vizsgáltuk a kamaszok pletyka- és reputációs hálózatának együttes változását. Igazolódott az a feltételezés, hogy a kamaszok hajlamosak idővel lenézni azokat a társaikat, akikről negatív tartalmú pletykát terjesztenek. Emellett azokról az osztálytársaikról, akiket lenéznek, idővel pletykálnak is.

Our study contributes to the debate on the evolution of cooperation in the single shot Prisoner's Dilemma (PD) played on networks. We construct a model in which individuals are connected with positive and negative ties. Some agents play sign-dependent strategies that use the sign of the relation as a shorthand for determining appropriate action toward the opponent. In the context of our model in which network topology, agent strategic types and relational signs coevolve, the presence of sign-dependent strategies catalyzes the evolution of cooperation. We highlight how the success of cooperation depends on a crucial aspect of implementation: whether we apply parallel or sequential strategy update. Parallel updating, with averaging of payoffs across interactions in the social neighborhood, supports cooperation in a much wider set of parameter values than sequential updating. Our results cast doubts about the realism and generalizability of models that claim to explain the evolution of cooperation but implicitly assume parallel updating. ; Our study contributes to the debate on the evolution of cooperation in the single-shot Prisoner's Dilemma (PD) played on networks. We construct a model in which individuals are connected with positive and negative ties. Some agents play sign-dependent strategies that use the sign of the relation as a shorthand for determining appropriate action toward the opponent. In the context of our model in which network topology, agent strategic types and relational signs coevolve, the presence of sign-dependent strategies catalyzes the evolution of cooperation. We highlight how the success of cooperation depends on a crucial aspect of implementation: whether we apply parallel or sequential strategy update. Parallel updating, with averaging of payoffs across interactions in the social neighborhood, supports cooperation in a much wider set of parameter values than sequential updating. Our results cast doubts about the realism and generalizability of models that claim to explain the evolution of cooperation but implicitly assume parallel updating.

It is not easy to rationalize how peer review, as the current grassroots of science, can work based on voluntary contributions of reviewers. There is no rationale to write impartial and thorough evaluations. If reviewers are unmotivated to carefully select high quality contributions, there is no risk in submitting low-quality work by authors. As a result, scientists face a social dilemma: if everyone acts according to his or her own self-interest, the outcome is low scientific quality. We examine how the increased relevance of public good benefits (journal impact factor), the editorial policy of handling incoming reviews, and the acceptance decisions that take into account reputational information, can help the evolution of high-quality contributions from authors. High effort from the side of reviewers is problematic even if authors cooperate: reviewers are still best off by producing low-quality reviews, which does not hinder scientific development, just adds random noise and unnecessary costs to it. We show with agent-based simulations why certain self-emerged current practices, such as the increased reliance on journal metrics and the reputation bias in acceptance, work efficiently for scientific development. Our results find no proper guidelines, however, how the system of voluntary peer review with impartial and thorough evaluations could be sustainable jointly with rapid scientific development.

The evolution of cooperation is one of the fundamental problems of both social sciences and biology. It is difficult to explain how a large extent of cooperation could evolve if individual free riding always provides higher benefits and chances of survival. In absence of direct reciprocation, it has been suggested that indirect reciprocity could potentially solve the problem of large scale cooperation. In this paper, we compare the chances of two forms of indirect reciprocity with each other: a blind one that rewards any partner who did good to previous partners, and an embedded one that conditions cooperation on good acts towards common acquaintances. We show that these two versions of indirect reciprocal strategies are not very different from each other in their efficiency. We also demonstrate that their success very much relies on the speed of evolution: their chances for survival are only present if evolutionary updates are not frequent. Robustness tests are provided for various forms of biases. ; The evolution of cooperation is one of the fundamental problems of both social sciences and biology. It is difficult to explain how a large extent of cooperation could evolve if individual free riding always provides higher benefits and chances of survival. In absence of direct reciprocation, it has been suggested that indirect reciprocity could potentially solve the problem of large scale cooperation. In this paper, we compare the chances of two forms of indirect reciprocity with each other: a blind one that rewards any partner who did good to previous partners, and an embedded one that conditions cooperation on good acts towards common acquaintances. We show that these two versions of indirect reciprocal strategies are not very different from each other in their efficiency. We also demonstrate that their success very much relies on the speed of evolution: their chances for survival are only present if evolutionary updates are not frequent. Robustness tests are provided for various forms of biases.