scholarly journals Computational Behavioral Models for Public Goods Games on Social Networks

Games ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 35 ◽  
Author(s):  
Marco Tomassini ◽  
Alberto Antonioni

Cooperation is a fundamental aspect of well-organized societies and public good games are a useful metaphor for modeling cooperative behavior in the presence of strong incentives to free ride. Usually, social agents interact to play a public good game through network structures. Here, we use social network structures and computational agent rules inspired by recent experimental work in order to develop models of agent behavior playing public goods games. The results of our numerical simulations based on a couple of simple models show that agents behave in a manner qualitatively similar to what has been observed experimentally. Computational models such as those presented here are very useful to interpret observed behavior and to enhance computationally the limited variation that is possible in the experimental domain. By assuming a priori reasonable individual behaviors, the easiness of running simulations could also facilitate exploration prior to any experimental work in order to vary and estimate a number of key parameters that would be very difficult, if not impossible, to change during the actual experiment.

2015 ◽  
Vol 12 (103) ◽  
pp. 20141203 ◽  
Author(s):  
The Anh Han ◽  
Luís Moniz Pereira ◽  
Tom Lenaerts

When creating a public good, strategies or mechanisms are required to handle defectors. We first show mathematically and numerically that prior agreements with posterior compensations provide a strategic solution that leads to substantial levels of cooperation in the context of public goods games, results that are corroborated by available experimental data. Notwithstanding this success, one cannot, as with other approaches, fully exclude the presence of defectors, raising the question of how they can be dealt with to avoid the demise of the common good. We show that both avoiding creation of the common good, whenever full agreement is not reached, and limiting the benefit that disagreeing defectors can acquire, using costly restriction mechanisms, are relevant choices. Nonetheless, restriction mechanisms are found the more favourable, especially in larger group interactions. Given decreasing restriction costs, introducing restraining measures to cope with public goods free-riding issues is the ultimate advantageous solution for all participants, rather than avoiding its creation.


Games ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 15 ◽  
Author(s):  
Kurt Ackermann ◽  
Ryan Murphy

There is a large body of evidence showing that a substantial proportion of people cooperate in public goods games, even if the situation is one-shot and completely anonymous. In the present study, we bring together two major endogenous factors that are known to affect cooperation levels, and in so doing replicate and extend previous empirical research on public goods problems in several important ways. We measure social preferences and concurrently elicit beliefs on the individual level using multiple methods, and at multiple times during the experiment. With this rich set of predictor variables at the individual level, we test how well individual contribution decisions can be accounted for in both a one-shot and a repeated interaction. We show that when heterogeneity in people’s preferences and beliefs is taken into consideration, more than 50% of the variance in individual choice behavior can be explained. Furthermore, we show that people do not only update their beliefs in a repeated public goods game, but also that their social preferences change, to some extent, in response to the choices of other decision makers.


2020 ◽  
Author(s):  
Brian Johnson ◽  
Philipp M. Altrock ◽  
Gregory J. Kimmel

AbstractPublic goods games (PGGs) describe situations in which individuals contribute to a good at a private cost, but others can free-ride by receiving their share of the public benefit at no cost. PGGs can be nonlinear, as often observed in nature, whereby either benefit, cost, or both are nonlinear functions of the available public good (PG): at low levels of PG there can be synergy whereas at high levels, the added benefit of additional PG diminishes. PGGs can be local such that the benefits and costs are relevant only in a local neighborhood or subset of the larger population in which producers (cooperators) and free-riders (defectors) co-evolve. Cooperation and defection can be seen as two extremes of a continuous spectrum of traits. The level of public good production, and similarly, the neighborhood size can vary across individuals. To better understand how distinct strategies in the nonlinear public goods game emerge and persist, we study the adaptive dynamics of production rate and neighborhood size. We explain how an initially monomorphic population, in which individuals have the same trait values, could evolve into a dimorphic population by evolutionary branching, in which we see distinct cooperators and defectors emerge, respectively characterized by high production and low neighborhood sizes, and low production and high neighborhood sizes. We find that population size plays a crucial role in determining the final state of the population, as smaller populations may not branch, or may observe extinction of a subpopulation after branching. Our work elucidates the evolutionary origins of cooperation and defection in nonlinear local public goods games, and highlights the importance of small population size effects on the process and outcome of evolutionary branching.


Author(s):  
Marco Tomassini ◽  
Alberto Antonioni

Abstract In this study we have simulated numerically two models of linear Public Goods Games where players are equally distributed among a given number of groups. Agents play in their group by using two simple sets of rules that are inspired by the observed behavior of human participants in laboratory experiments. In addition, unsatisfied agents have the option of leaving their group and migrating to a new random one through probabilistic choices. Stochasticity, and the introduction of two types of players in the population, help simulate the heterogeneous behavior that is often observed in experimental work. The numerical simulation results of the corresponding dynamical systems show that being able to leave a group when unsatisfied favors contribution and avoids free-riding to a good extent in a range of the enhancement factor where defection would prevail without migration. Our numerical simulation results are qualitatively in line with known experimental data when human agents are given the same kind of information about themselves and the other players in the group. This is usually not the case with customary mathematical models based on replicator dynamics or stochastic approaches. As a consequence, models like the ones described here may be useful for understanding experimental results and also for designing new experiments by first running cheap simulations instead of doing costly preliminary laboratory work. The downside is that models and their simulation tend to be less general than standard mathematical approaches.


2015 ◽  
Vol 282 (1798) ◽  
pp. 20141994 ◽  
Author(s):  
Miguel dos Santos

Cooperation in joint enterprises can easily break down when self-interests are in conflict with collective benefits, causing a tragedy of the commons. In such social dilemmas, the possibility for contributors to invest in a common pool-rewards fund, which will be shared exclusively among contributors, can be powerful for averting the tragedy, as long as the second-order dilemma (i.e. withdrawing contribution to reward funds) can be overcome (e.g. with second-order sanctions). However, the present paper reveals the vulnerability of such pool-rewarding mechanisms to the presence of reward funds raised by defectors and shared among them (i.e. anti-social rewarding), as it causes a cooperation breakdown, even when second-order sanctions are possible. I demonstrate that escaping this social trap requires the additional condition that coalitions of defectors fare poorly compared with pro-socials, with either (i) better rewarding abilities for the latter or (ii) reward funds that are contingent upon the public good produced beforehand, allowing groups of contributors to invest more in reward funds than groups of defectors. These results suggest that the establishment of cooperation through a collective positive incentive mechanism is highly vulnerable to anti-social rewarding and requires additional countermeasures to act in combination with second-order sanctions.


2018 ◽  
Author(s):  
Gregory J. Kimmel ◽  
Philip Gerlee ◽  
Joel S. Brown ◽  
Philipp M. Altrock

Ecological and evolutionary dynamics can be strongly affected by population assortment and frequency-dependent selection. In growing populations, a particular challenge is to disentangle global ecological effects from local frequency-dependent effects. Here we implement a logistic growth and death model on the global scale, coupled to frequency-dependent growth rates influenced by a public goods game between cooperators and defectors. For each individual, the public good is only effective within a neighborhood of other individuals, and the public good-growth rate relationship can be nonlinear. At low numbers of cooperators, increases of public good accumulate synergistically; at high numbers, increases in public good only provide diminishing returns-the inflection point of this pattern is given by the strength of frequency-dependent selection in relation to the background fitness effect. We observed complex critical behavior in the evolutionary dynamics’ equilibria, determined by the relative magnitude of frequency-dependent to constant (background) growth benefits. We predict neighborhood-size-driven state changes, hysteresis between polymorphic and monomorphic equilibria, and observed that type-dependent differences in neighborhood sizes can destabilize monomorphic cooperative states but increase coexistence of cooperators and defectors. Stochastic neighborhood size fluctuations also led to coexistence and could stabilize the purely cooperative equilibrium. Our results quantify the role of assortment through neighborhood-size effects and nonlinearity of the gains function in eco-evolutionary dynamics, which is relevant for a variety of microbial and cellular public goods games.


2015 ◽  
Vol 197 (19) ◽  
pp. 3154-3159 ◽  
Author(s):  
Nicole E. Smalley ◽  
Dingding An ◽  
Matthew R. Parsek ◽  
Josephine R. Chandler ◽  
Ajai A. Dandekar

ABSTRACTMany species of bacteria use a cell-cell communication system called quorum sensing (QS) to coordinate group activities. QS systems frequently regulate the production of exoproducts. Some of these products, such as proteases, are “public goods” that are shared among the population and vulnerable to cheating by nonproducing members of the population. Because the QS system of the opportunistic pathogenPseudomonas aeruginosaregulates several public goods, it can serve as a model for studying cooperation. Bacteria also commonly regulate antimicrobial production through QS. In this study, we focused on the hypothesis that QS-regulated antimicrobials may be important forP. aeruginosato protect against cheating by another bacterial species,Burkholderia multivorans.We assessed laboratory cocultures ofP. aeruginosaandB. multivoransand investigated the importance of threeP. aeruginosaQS-regulated antimicrobials, hydrogen cyanide, rhamnolipids, and phenazines, for competition. We found thatP. aeruginosadominates cocultures withB. multivoransand that the three antimicrobials together promoteP. aeruginosacompetitiveness, with hydrogen cyanide contributing the greatest effect. We show that these QS-regulated antimicrobials are also critical forP. aeruginosato preventB. multivoransfrom cheating under nutrient conditions where both species require aP. aeruginosaquorum-regulated protease for growth. Together our results highlight the importance of antimicrobials in protecting cooperating populations from exploitation by other species that can act as cheaters.IMPORTANCECooperative behaviors are threatened by social cheating, wherein individuals do not produce but nonetheless benefit from shared public goods. Bacteria have been shown to use several genetic mechanisms to restrain the emergence of cheaters from within the population, but public goods might also be used by other bacterial species in the vicinity. We demonstrate that a public good produced byPseudomonas aeruginosacan be used by another species,Burkholderia multivorans, to obtain carbon and energy. We also show thatP. aeruginosaantimicrobials that are coregulated with the public good prevent invasion by the cheating species. Our results demonstrate that cross-species cheating can occur and that coregulation of public goods with antimicrobials may stabilize cooperative behavior in mixed microbial communities.


2021 ◽  
Author(s):  
Paul Deutchman ◽  
Dorsa Amir ◽  
Katherine McAuliffe ◽  
Matthew Jordan

Recent work suggests that an important cognitive mechanism promoting coordination is common knowledge—a heuristic for representing recursive mental states. Yet, we know little about how common knowledge promotes coordination. We propose that common knowledge increases coordination by reducing uncertainty about others’ cooperative behavior. We examine how common knowledge increases cooperation in the context of a threshold public goods game, a public good game in which a minimum level of contribution—a threshold—is required. Across two preregistered studies (N = 4,111), we explored how varying (1) the information participants had regarding what their group members knew about the threshold and (2) the threshold level affected contributions. We found that participants were more likely to contribute to the public good when there was common knowledge of the threshold than private knowledge. Using structural equation modeling, we found that the predicted number of group members contributing to the public good and certainty about the predicted number of contributors mediated the effect of information condition on contributions. Our results suggest that common knowledge of the threshold increases public good contributions by reducing uncertainty around other people’s cooperative behavior. These findings point to the influential role of common knowledge in helping to solve large-scale cooperation problems.


2012 ◽  
Vol 15 (supp01) ◽  
pp. 1250056 ◽  
Author(s):  
CHENG-YI XIA ◽  
SANDRO MELONI ◽  
YAMIR MORENO

Nowadays, our society is characterized by high levels of social cohesion and cooperation that are in contrast with the selfish nature of human beings. One of the principal challenges for the social sciences is to explain the emergence of agglomeration and cooperative behavior in an environment characterized by egoistic individuals. In this paper we address this long standing problem with the tools given by evolutionary game theory. Specifically, we explore a model in which selfish individuals interact in a public goods creation environment. As a further ingredient each agent is characterized by an individual expectation and, if unsatisfied, can change its location. In this scenario we study the effects of the knowledge of other players' performances on both cooperation and agglomeration and discuss the results in the context of previous and related works. Our results show that cooperation and agglomeration are generally robust against the inclusion of different information on other player performances and, in some cases, it can produce an enhancement of the cooperative behavior. Moreover, our results demonstrate that only in extreme and very competitive environments cooperation and agglomeration are lost.


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