scholarly journals Neighborhood size-effects in nonlinear public goods games

2018 ◽  
Author(s):  
Gregory J. Kimmel ◽  
Philip Gerlee ◽  
Joel S. Brown ◽  
Philipp M. Altrock
Keyword(s):  
Public Goods ◽  
Public Good ◽  
Size Effects ◽  
Evolutionary Dynamics ◽  
Logistic Growth ◽  
Neighborhood Size ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
The Public ◽  
Public Goods Games

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.

scholarly journals Evolutionary dynamics in the public goods games with switching between punishment and exclusion

2018 ◽  
Vol 28 (10) ◽  
pp. 103105 ◽  
Author(s):  
Linjie Liu ◽  
Shengxian Wang ◽  
Xiaojie Chen ◽  
Matjaž Perc
Keyword(s):  
Public Goods ◽  
Evolutionary Dynamics ◽  
The Public ◽  
Public Goods Games

scholarly journals Branching and extinction in evolutionary public goods games

2020 ◽  
Author(s):  
Brian Johnson ◽  
Philipp M. Altrock ◽  
Gregory J. Kimmel
Keyword(s):  
Public Goods ◽  
Public Good ◽  
Population Size ◽  
Adaptive Dynamics ◽  
Small Population ◽  
Neighborhood Size ◽  
Evolutionary Branching ◽  
Final State ◽  
Evolutionary Origins ◽  
Public Goods Games

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.

scholarly journals The evolution of anti-social rewarding and its countermeasures in public goods games

2015 ◽  
Vol 282 (1798) ◽  
pp. 20141994 ◽  
Author(s):  
Miguel dos Santos
Keyword(s):  
Public Goods ◽  
Public Good ◽  
Additional Condition ◽  
Social Dilemmas ◽  
Second Order ◽  
The Public ◽  
Common Pool ◽  
Public Goods Games ◽  
The Commons ◽  
Social Trap

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.

scholarly journals Evolution of contribution timing in public goods games

2020 ◽  
Vol 287 (1927) ◽  
pp. 20200735
Author(s):  
Bryce Morsky ◽  
Marco Smolla ◽  
Erol Akçay
Keyword(s):  
Public Goods ◽  
Public Good ◽  
Group Living ◽  
Theoretical Models ◽  
Spatial Diversity ◽  
Life History Strategies ◽  
The Public ◽  
Second Stage ◽  
Public Goods Games ◽  
Living Species

Life-history strategies are a crucial aspect of life, which are complicated in group-living species, where pay-offs additionally depend on others’ behaviours. Previous theoretical models of public goods games have generally focused on the amounts individuals contribute to the public good. Yet a much less-studied strategic aspect of public goods games, the timing of contributions, can also have dramatic consequences for individual and collective performance. Here, we develop two stage game theoretical models to explore how the timing of contributions evolves. In the first stage, individuals contribute to a threshold public good based on a performance schedule. The second stage begins once the threshold is met, and the individuals then compete as a function of their performance. We show how contributing rapidly is not necessarily optimal, because delayers can act as ‘cheats,’ avoiding contributing while reaping the benefits of the public good. However, delaying too long can put the delayers at a disadvantage as they may be ill-equipped to compete. These effects lead to bistability in a single group, and spatial diversity among multiple interacting groups.

Ethnic trust, minority status, and public goods in post-conflict societies

2021 ◽  
pp. 002234332098421
Author(s):  
Sam Whitt
Keyword(s):  
Public Goods ◽  
Public Good ◽  
Intergroup Contact ◽  
Minority Group ◽  
Civil Liberties ◽  
Minority Status ◽  
The Public ◽  
Attitudes And Behaviors ◽  
Post Conflict ◽  
History Of

This study considers how ethnic trust and minority status can impact the ability of ethnic groups to pursue cooperative public goods, focusing on groups with a history of conflict and lingering hostility. A public good experiment between ethnic Albanians and Serbs in postwar Kosovo reveals that subjects contribute far more to a mutually beneficial public good when they are part of an experimentally induced coethnic majority. However, when in the minority, subjects not only underinvest, but many actively divest entirely, privatizing the public good. Majority/minority status also has wide-ranging implications for how individuals relate to real-world public goods and the institutions of government that provide them. Compared to majority Albanians, survey data indicate how minority Serbs in Kosovo express greater safety and security concerns, feel more politically, socially, and economically excluded, are more dissatisfied with civil liberties and human rights protections, and are less likely to participate politically or pay taxes to support public goods. Conflict-related victimization and distrust of out-groups are strong predictors of these minority group attitudes and behaviors. This suggests a mechanism for how conflict amplifies out-group distrust, increasing parochial bias in public good commitments, especially among minorities who are wary of exploitation at the hands of an out-group majority. To restore trust, this study finds that institutional trust and intergroup contact are important to bridging ethnic divides that inhibit public good cooperation.

scholarly journals Avoiding or restricting defectors in public goods games?

2015 ◽  
Vol 12 (103) ◽  
pp. 20141203 ◽  
Author(s):  
The Anh Han ◽  
Luís Moniz Pereira ◽  
Tom Lenaerts
Keyword(s):  
Experimental Data ◽  
Public Goods ◽  
Public Good ◽  
Common Good ◽  
Full Agreement ◽  
Group Interactions ◽  
The Common Good ◽  
Public Goods Games ◽  
The Common ◽  
Strategic Solution

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.

A Case for Private Provision but Collective Ownership of Public Goods

1998 ◽  
Vol 42 (1) ◽  
pp. 90-94 ◽  
Author(s):  
William D. Gerdes
Keyword(s):  
Public Goods ◽  
Public Good ◽  
Private Provision ◽  
The Public ◽  
Collective Ownership ◽  
Free Ride ◽  
Voluntary Exchange

One strategy for generating Pareto results in a public good model is to create an environment where traders internalize the public good externality. The model presented here accomplishes this by separating the provision and ownership of public goods. Such goods are privately provided but collectively owned. Under this arrangement, Lindahl prices are generated through the voluntary exchange activities of consumers. Persistent attempts to free ride are not consistent with maximizing behavior which leads to internalization.

scholarly journals Negative frequency-dependent selection maintains coexisting genotypes during fluctuating selection

2019 ◽  
Author(s):  
Caroline B. Turner ◽  
Sean W. Buskirk ◽  
Katrina B. Harris ◽  
Vaughn S. Cooper
Keyword(s):  
Evolutionary Dynamics ◽  
Burkholderia Cenocepacia ◽  
Natural Environments ◽  
Fluctuating Selection ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Fluctuating Environment ◽  
Fluctuating Environments ◽  
Negative Frequency Dependent Selection ◽  
Selection For

AbstractNatural environments are rarely static; rather selection can fluctuate on time scales ranging from hours to centuries. However, it is unclear how adaptation to fluctuating environments differs from adaptation to constant environments at the genetic level. For bacteria, one key axis of environmental variation is selection for planktonic or biofilm modes of growth. We conducted an evolution experiment with Burkholderia cenocepacia, comparing the evolutionary dynamics of populations evolving under constant selection for either biofilm formation or planktonic growth with populations in which selection fluctuated between the two environments on a weekly basis. Populations evolved in the fluctuating environment shared many of the same genetic targets of selection as those evolved in constant biofilm selection, but were genetically distinct from the constant planktonic populations. In the fluctuating environment, mutations in the biofilm-regulating genes wspA and rpfR rose to high frequency in all replicate populations. A mutation in wspA first rose rapidly and nearly fixed during the initial biofilm phase but was subsequently displaced by a collection of rpfR mutants upon the shift to the planktonic phase. The wspA and rpfR genotypes coexisted via negative frequency-dependent selection around an equilibrium frequency that shifted between the environments. The maintenance of coexisting genotypes in the fluctuating environment was unexpected. Under temporally fluctuating environments coexistence of two genotypes is only predicted under a narrow range of conditions, but the frequency-dependent interactions we observed provide a mechanism that can increase the likelihood of coexistence in fluctuating environments.

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