Evolutionary Game Theory

Mesoscopic Effects in an Agent-Based Bargaining Model in Regular Lattices

by Jose Manuel Galan

Evolution of Equity Norms in Small-World Networks

by Jose Manuel Galan

The topology of interactions has been proved very influential in the results of models based on learning and... more The topology of interactions has been proved very influential in the results of models based on learning and evolutionary game theory. This paper is aimed at investigating the effect of structures ranging from regular ring lattices to random networks, including small-world networks, in a model focused on property distribution norms. The model considers a fixed and finite population of agents who play the Nash bargaining game repeatedly. Our results show that regular networks promote the emergence of the equity norm, while less-structured networks make possible the appearance of fractious regimes. Additionally, our analysis reveals that the speed of adoption can also be affected by the network structure.

Axelrod's Metanorm Games on Networks

by Jose Manuel Galan

Appearances can be deceiving: Lessons learned re-implementing Axelrod's' evolutionary approach to norms'

by Jose Manuel Galan

Modelling evolutionarily stable strategies in oviposition site selection, with varying risks of predation and intraspecific competition

by Arik Kershenbaum

Many ovipositing mosquitoes, as well as other species, can detect biotic factors that affect fitness. However, a... more Many ovipositing mosquitoes, as well as other species, can detect biotic factors that affect fitness. However, a female mosquito seeking a high quality oviposition site (e.g. one with low risk of predation and competition to her progeny) must often balance the competing risk of increasing probability of mortality to herself while she continues to search, against increased probability of finding a high quality site. Such oviposition site selection may affect adult population size. We examined a female mosquito’s expected strategy of oviposition site selection under conditions of varying predator prevalence and adult mortality risk, by combining a detailed structured population model with a Markov chain implementation of the adult behavioural process. We used parameter values from the specific mosquito-predator system, Culiseta longiareolata-Notonecta maculata, although the overall results can be generalised to many mosquito species. Our model finds the evolutionarily stable strategy of oviposition site selection for different parameter combinations. Our model predicts that oviposition strategy does not vary smoothly with varying environmental risk of adult mortality, but that certain oviposition strategies become unstable at some parameter values. Mosquitoes will distribute their reproductive effort between breeding sites of varying predation risk only when adult mortality is low or larval competition high. Our model predicts that females will continue searching for predator-free pools, rather than oviposit in the first site encountered, regardless of the risk of mortality to the adult. The ecological basis for a reproductive strategy with alternative behaviours is important for understanding the effect of biotic factors on the population dynamics of mosquitoes, and for the development of biological control strategies, such as the dissemination of predator-cue chemicals.

Did Veblen Generalize Darwinism (And Why Does It Matter)?

by Cyril Hédoin

published in the 'Journal of Economic Issues'"

The 'Evolutionary Turn' of Game Theory and the Ontology of the Socioeconomic World: What Do Evolutionary Game-Theoretic Models Represent?

by Cyril Hédoin

Working paper

Intention Recognition, Commitment, and The Evolution of Cooperation.

by The Anh Han

Co-authored with L. M. Pereira and F. C. Santos.
In Proceedings of the 2012 IEEE Congress on Evolutionary Computation (CEC 2012), IEEE Press, Brisbane, Australia.

Individuals make commitments towards others in order to influence others to behave in certain ways. Most commitments... more Individuals make commitments towards others in order to influence others to behave in certain ways. Most commitments may depend on some incentive that is required to ensure that the action is in the agent's best interest and thus, should be carried out to avoid eventual penalties. Similarly, individuals may ground their decision on an accurate assessment of the intentions of others. Hence, both commitments and intention recognition go side by side in behavioral evolution. Here, we analyze the role played by the co-evolution of intention recognition plus the emergence of commitments, in the framework of the evolution of cooperative behavior. We resort to tools of evolutionary game theory in finite populations, showing how the combination of these two aspects of human behavior can enhance the emergent fraction of cooperative acts under a broad spectrum of configurations.

On equilibrium properties of evolutionary multiplayer games with random payoff matrices

by The Anh Han

co-authored with A. Traulsen and C. S. Gokhale.
Journal of Theoretical Population Biology (in press)

The analysis of equilibrium points in biological dynamical systems has been of great interest in a variety of... more The analysis of equilibrium points in biological dynamical systems has been of great interest in a variety of mathematical approaches to biology, such as population genetics, theoretical ecology or evolutionary game theory. The maximal number of equilibria and their classification based on stability have been the primary subjects of these studies, for example in the context of two-player games with multiple strategies. Herein, we address a different question using evolutionary game theory as a tool. If the payoff matrices are drawn randomly from an arbitrary distribution, what are the probabilities of observing a certain number of (stable) equilibria? We extend the domain of previous results for the two-player framework, which corresponds to a single diploid locus in population genetics, by addressing the full complexity of multi-player games with multiple strategies. In closing, we discuss an application and illustrate how previous results on the number of equilibria, such as the famous Feldman–Karlin conjecture on the maximal number of isolated fixed points in a viability selection model, can be obtained as special cases of our results based on multi-player evolutionary games. We also show how the probability of realizing a certain number of equilibria changes as we increase the number of players and number of strategies.

Game theory and moral norms: an overview and an application

by Bruno Verbeek

Probabilistic participation in public goods games

by Tatsuya Sasaki

Replicator dynamics in public goods games with reward funds

by Tatsuya Sasaki

Co-authored with Tatsuo Unemi (Soka Univ., Japan); preprint; published in 'Journal of Theoretical Biology', 2011

Which punishment or rewards are most effective at maintaining cooperation in public goods interactions and deterring... more Which punishment or rewards are most effective at maintaining cooperation in public goods interactions and deterring defectors who are willing to freeload on others’ contribution? The sanction system is itself a public good and can cause problematic “second-order free riders” who do not contribute to the provisions of the sanctions and thus may subvert the cooperation supported by sanctioning. Recent studies have shown that public goods games with punishment can lead to a coercion-based regime if participation in the game is optional. Here, we reveal that even with compulsory participation, rewards can maintain cooperation within an infinitely large population. We consider three strategies for players in a standard public goods game: to be a cooperator or a defector in a standard public goods game, or to be a rewarder who contributes to the public good and to a fund that rewards players who contribute during the game. Cooperators do not contribute to the reward fund and are therefore classified as second-order free riders. The replicator dynamics for the three strategies exhibit a rock-scissors-paper cycle, and can be analyzed fully, despite the fact that the expected payoffs are nonlinear. The model does not require repeated interaction, spatial structure, group selection, or reputation. We also discuss a simple method for second-order sanctions, which can lead to a globally stable state where 100% of the population are rewarders.

Quantum 2-player gambling and correlated pay-off

by Frank Witte

In recent years methods have been proposed to extend classical game theory into the quantum domain. In a previous... more In recent years methods have been proposed to extend classical game theory into the quantum domain. In a previous publication the nature of several non-cummutative games was briefly analyzed.

Here we give an analysis of the simplest non-commutative quantum game, which is a gambling game much like simple heads or tails. The quantum game displays strategies which, though non direct-product strategies, allow for correlations between the players pay-off.

How to assemble a beneficial microbiome in three easy steps

by Douglas Yu

Istvan Scheuring and Douglas W. Yu. Manuscript.

There is great interest in explaining how beneficial microbiomes are assembled. An exemplar is the attine ants, which... more There is great interest in explaining how beneficial microbiomes are assembled. An exemplar is the attine ants, which cultivate a fungal garden for food and also host a cuticular microbiome that releases antibiotics to defend the garden from parasites. One explanation posits long-term vertical transmission of Pseudonocardia bacteria, which (somehow) continuously evolve compounds in arms-race fashion against parasites. Alternatively, attines are argued to selectively take up (somehow) multiple, non-coevolved actinobacterial genera from the soil, enabling a multi-drug strategy against parasites. We reconcile these two explanations by showing that when hosts provide high resource levels, interference competition is fuelled, and the recruitment of antibiotic-producing (and resistant) bacteria is thereby favored. This partner-choice mechanism is more likely to work if at least one actinobacterial symbiont is vertically transmitted or has a high immigration rate, providing a key role for Pseudonocardia in the attine symbiosis. Our model can also apply to the very wide range of hosts that house antibiotic-producing microbes, including vertebrates, mollusks, arthropods, corals, and plant rhizospheres.

The Emergence of Commitments and Cooperation

by The Anh Han

co-authored with L.M. Pereira and F.C.Santos, In Proceedings of the 11th International Conference on Autonomous Agents and Multi-agent Systems (AAMAS 2012), Forthcoming.

Agents make commitments towards others in order to influence others in a certain way, often by dismissing more... more Agents make commitments towards others in order to influence others in a certain way, often by dismissing more profitable options. Most commitments depend on some incentive that is necessary to ensure that the action is in the agent's interest and thus, may be carried out to avoid eventual penalties. The capacity for using commitment strategies effectively is so important that natural selection may have shaped specialized capacities to make this possible. Evolutionary explanations for commitment, particularly its role in the evolution of cooperation, have been actively sought for and discussed in several fields, including Psychology and Philosophy. In this paper, using the tools of evolutionary game theory, we provide a new model showing that individuals tend to engage in commitments, which leads to the emergence of cooperation even without assuming repeated interactions. The model is characterized by two key parameters: the punishment cost of failing commitment imposed on either side of a commitment, and the cost of managing the commitment deal. Our analytical results and extensive computer simulations show that cooperation can emerge if the punishment cost is large enough compared to the management cost.

Information-theoretic metamodel of organization evolution

by Alfred Sepulveda

PhD dissertation

Social organizations are abstractly modeled by holarchies--self-similar connected networks--and intelligent complex... more Social organizations are abstractly modeled by holarchies--self-similar connected networks--and intelligent complex adaptive multiagent systems--large networks of autonomous reasoning agents interacting via scaled processes. However, little is known of how information shapes evolution in such organizations, a gap that can lead to misleading analytics. The research problem addressed in this study was the ineffective manner in which classical model-predict-control methods used in business analytics attempt to define organization evolution. The purpose of the study was to construct an effective metamodel for organization evolution based on a proposed complex adaptive structure--the info-holarchy. Theoretical foundations of this study were holarchies, complex adaptive systems, evolutionary theory, and quantum mechanics, among other recently developed physical and information theories. Research questions addressed how information evolution patterns gleamed from the study's inductive metamodel more aptly explained volatility in organization. In this study, a hybrid grounded theory based on abstract inductive extensions of information theories was utilized as the research methodology. An overarching heuristic metamodel was framed from the theoretical analysis of the properties of these extension theories and applied to business, neural, and computational entities. This metamodel resulted in the synthesis of a metaphor for, and generalization of organization evolution, serving as the recommended and appropriate analytical tool to view business dynamics for future applications. This study may manifest positive social change through a fundamental understanding of complexity in business from general information theories, resulting in more effective management.

A Review of Evolutionary Graph Theory With Applications to Game Theory

by Paulo Shakarian

Paulo Shakarian, Patrick Roos, Anthony Johnson, BioSystems, Elsevier, accepted, 2011.

Evolutionary graph theory (EGT), studies the ability of a mutant gene to overtake a nite structured population. In... more Evolutionary graph theory (EGT), studies the ability of a mutant gene to overtake a nite structured population. In this review, we describe the original framework for EGT and the major work that has followed it. This review looks at the calculation of the "fixation probability" - the probability of a mutant taking over a population and focuses on game-theoretic applications. We look at varying topics such as alternate evolutionary dynamics, time to fixation, special topological cases, and game theoretic results. Throughout the review, we examine several interesting open problems that warrant further research.

Two-level Fisher-Wright framework with selection and migration: An approach to studying evolution in group structured populations

by Renato Vicente

A framework for the mathematical modeling of evolution in group structured populations is introduced. The population... more A framework for the mathematical modeling of evolution in group structured populations is introduced. The population is divided into a fixed large number of groups of fixed size. From generation to generation, new groups are formed that descend from previous groups, through a two-level Fisher-Wright process, with selection between groups and within groups and with migration between groups at rate $m$. When $m=1$, the framework reduces to the often used trait-group framework, so that our setting can be seen as an extension of that approach. Our framework allows the analysis of previously introduced models in which altruists and non-altruists compete, and provides new insights into these models. We focus on the situation in which initially there is a single altruistic allele in the population, and no further mutations occur. The main questions are conditions for the viability of that altruistic allele to spread, and the fashion in which it spreads when it does. Because our results and methods are rigorous, we see them as shedding light on various controversial issues in this field, including the role of Hamilton's rule, and of the Price equation, the relevance of linearity in fitness functions and the need to only consider pairwise interactions, or weak selection. In this paper we analyze the early stages of the evolution, during which the number of altruists is small compared to the size of the population. We show that during this stage the evolution is well described by a multitype branching process. The driving matrix for this process can be obtained, reducing the problem of determining when the altruistic gene is viable to a comparison between the leading eigenvalue of that matrix, and the fitness of the non-altruists before the altruistic gene appeared. This leads to a generalization of Hamilton's condition for the viability of a mutant gene.

Laxenburg TECT: Reflections on a literature that GIScientists and Historians do not know

by J. B. (Jack) Owens

Report for the DynCoopNet Project, TECT (The Evolution of Cooperation and Trading), EUROCORES Scheme, European Science Foundation

Report on the TECT Conference at the International Institute of Applied Systems Analysis (IIASA), Laxenburg, Austria,... more Report on the TECT Conference at the International Institute of Applied Systems Analysis (IIASA), Laxenburg, Austria, 15-18 September 2009. Conference title: “Evolution of Cooperation: Models and Theories”; prepared especially for the nineteen core researchers of the TECT project “Dynamic complexity of self-organizing, cooperation-based commercial networks in the first global age”, who were excluded from participation by the collapse of TECT networking funds. The DynCoopNet Project within TECT focuses on cooperation within the networks linking the global domains of Iberian Monarchies during the First Global Age, 1400-1800.

Economic Game Theory for Mutualism and Cooperation

by Douglas Yu

Archetti, M., Scheuring, I., Hoffman, M., Frederickson, M.E., Pierce, N.E., Yu, D.W. 2011. Economic game theory for mutualism and cooperation. Ecology Letters. doi: 10.1111/j.1461-0248.2011.01697.x

We review recent work at the interface of economic game theory and evolutionary biology that provides new insights... more We review recent work at the interface of economic game theory and evolutionary biology that provides new insights into the evolution of partner choice, host sanctions, partner fidelity feedback, and public goods. (1) The theory of games with asymmetric information shows that the right incentives allow hosts to screen-out parasites and screen-in mutualists, explaining successful partner choice in the absence of signalling. Applications range from ant-plants to microbiomes. (2) Contract theory distinguishes two longstanding but weakly differentiated explanations of host response to cheaters: host sanctions and partner fidelity feedback. Host traits that selectively punish misbehaving symbionts are parsimoniously interpreted as pre-adaptations. Yucca-moth and legume-rhizobia mutualisms are argued to be examples of partner fidelity feedback. (3) The theory of public goods shows that cooperation in multi-player interactions can evolve in the absence of assortment, in one-shot social dilemmas among non-kin. Applications include alarm calls in vertebrates and exoenzymes in microbes.