1,721,127 research outputs found
Short versus long term benefits and the evolution of cooperation in the prisoner's dilemma game
No full textIn this paper I investigate the evolution of cooperation in the prisoner's dilemma when individuals change their strategies subject to performance evaluation of their neighbours over variable time horizons. In the monochrome setting, in which all agents per default share the same performance evaluation rule, weighing past events strongly dramatically enhances the prevalence of cooperators. For co-evolutionary models, in which evaluation time horizons and strategies can co-evolve, I demonstrate that cooperation naturally associates with long-term evaluation of others while defection is typically paired with very short time horizons. Moreover, considering the continuous spectrum in between enhanced and discounted weights of past performance, cooperation is optimally supported when cooperators neither give enhanced weight to past nor more recent events, but simply average payoffs. Payoff averaging is also found to emerge as the dominant strategy for cooperators in co-evolutionary models, thus proposing a natural route to the evolution of cooperation in viscous populations
Construction principles for highly synchronizable sparse directed networks
No full textIn this Letter sparse directed interaction networks of heterogeneous Kuramoto oscillators that give rise to enhanced synchronization properties are generated and analyzed. The particular networks, which allow for the transition to full synchronization for the smallest coupling strength, i.e., optimal networks, are found to be very homogeneous in the in-degree distribution, but exhibit very skewed out-degree distributions. Various correlations between in- and out-degree structure, oscillator heterogeneity and component structure, which are linked to an enhanced synchronizability, are discussed
Preferential opponent selection in public goods games
Full text linkThis paper discusses preferential opponent selection in public goods games. It is shown that a preference to play with successful opponents strongly enhances the prevalence of cooperation. The finding is robust on spatial grids and heterogeneous networks. Importantly, I also demonstrate that positive opponent selection biases can evolve and become dominant in initially randomly mixed populations without selection bias
Costly advertising and the evolution of cooperation
No full textIn this paper I investigate the co-evolution of fast and slow strategy spread and game strategies in populations of spatially distributed agents engaged in a one off evolutionary dilemma game. Agents are characterized by a pair of traits, a game strategy (cooperate or defect) and a binary 'advertising' strategy (advertise or don't advertise). Advertising, which comes at a cost, a, allows investment into faster propagation of the agents traits to adjacent individuals. Importantly, game strategy and advertising strategy are subject to the same evolutionary mechanism. Via analytical reasoning and numerical simulations I demonstrate that a range of advertising costs exists, such that the prevalence of cooperation is significantly enhanced through co-evolution. Linking costly replication to the success of cooperators exposes a novel co-evolutionary mechanism that might contribute towards a better understanding of the origins of cooperation-supporting heterogeneity in agent populations
The prisoner's dilemma with image scoring on networks: How does a player's strategy depend on its place in the social network?
No full textWe investigate the evolution of cooperation in the prisoner's dilemma on different types of interaction networks. Agents interact with their network neighbours. An agent is classified by a value S is an element of [-1, 1] denoting its strategy and by its image score. It will cooperate if the opponents relative image score is above S and defect otherwise. Agents spread their strategies to their network neighbours proportionally to payoff differences. We find that network topology strongly influences the average cooperation rate; networks with low degree variance allowing for the largest amount of cooperation. In heterogeneous networks an agents place in the network strongly influences its strategy. Thus, agents on hub nodes are found to 'police' the population, while being on low degree nodes tends to favour over-generous less discriminating strategies
Optimal synchronization in space
No full textIn this Rapid Communication we investigate spatially constrained networks that realize optimal synchronization properties. After arguing that spatial constraints can be imposed by limiting the amount of “wire” available to connect nodes distributed in space, we use numerical optimization methods to construct networks that realize different trade offs between optimal synchronization and spatial constraints. Over a large range of parameters such optimal networks are found to have a link length distribution characterized by power-law tails P(l)?l??, with exponents ? increasing as the networks become more constrained in space. It is also shown that the optimal networks, which constitute a particular type of small world network, are characterized by the presence of nodes of distinctly larger than average degree around which long-distance links are centered
Synchrony-optimized networks of non-identical Kuramoto oscillators
No full textIn this Letter we discuss a method for generating synchrony-optimized coupling architectures of Kuramoto oscillators with a heterogeneous distribution of native frequencies. The method allows us to relate the properties of the coupling network to its synchronizability. These relations were previously only established from a linear stability analysis of the identical oscillator case. We further demonstrate that the heterogeneity in the oscillator population produces heterogeneity in the optimal coupling network as well. Two rules for enhancing the synchronizability of a given network by a suitable placement of oscillators are given: (i) native frequencies of adjacent oscillators must be anti-correlated and (ii) frequency magnitudes should positively correlate with the degree of the node they are placed at
Information seeking as an evolutionary game
No full textIn this paper we present a game-theoretical model of rumour propagation on social networks. Agents face a choice between making investments at some cost to establish the truth about some underlying fact or copy the views of their network neighbours at no cost. Agents are also assumed to derive a benefit from knowledge about the truth. Considering rumour propagation at a fast time-scale and strategy adaptation at a slower time-scale, we present analysis of outcomes of the resulting evolutionary game. Depending on network structure and cost-benefit ratios, transitions between one and two-cluster solutions, either marked by the existence of only one type of strategy or coexistence of two strategies with low and high investments are found. We establish that clustering in the social network typically suppress the two-cluster solution, thus inhibiting the spread of high-investment strategies and leading to lower population-level awareness of the truth. Moreover, we also investigate the influence of free provision of additional high-quality information by stubborn agents. Counter-intuitively, we find that the presence of suchagents encourages free riding -- an effect that over-compensates the increased presence of higher quality information and has overall detrimentaleffects on the population
Optimizing spatially embedded networks for synchronization
No full textIn this paper we consider the problem of organizing networks of spatially embedded oscillators to maximize the propensity for synchronization for limited availability of wire, needed to realize the physical connections between the oscillators. We consider two extensions of previous work (Brede, 2010b): (i) oscillators that can flexibly arrange in space during the optimization process and (ii) a generalization to weighted networks. In the first case, we discuss the emergence of spatially and relationally modular network organizations, while in the second case the emphasis of our analysis is on link heterogeneity and the particular organization of strong and weak links that facilitates synchronization in space
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