Participation costs dismiss the advantage of heterogeneous networks in evolution of cooperation.
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ABSTRACT:
SUBMITTER: Masuda N
PROVIDER: S-EPMC2270926 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Analyses of the evolution of cooperation often rely on two simplifying assumptions: (i) individuals interact equally frequently with all social network members and (ii) they accurately remember each partner's past cooperation or defection. Here, we examine how more realistic, skewed patterns of contact-in which individuals interact primarily with only a subset of their network's members-influence cooperation. In addition, we test whether skewed contact patterns can counteract the decrease in cooperation caused by memory errors (i.e. forgetting). Finally, we compare two types of memory error that vary in whether forgotten interactions are replaced with random actions or with actions from previous encounters. We use evolutionary simulations of repeated prisoner's dilemma games that vary agents' contact patterns, forgetting rates and types of memory error. We find that highly skewed contact patterns foster cooperation and also buffer the detrimental effects of forgetting. The type of memory error used also influences cooperation rates. Our findings reveal previously neglected but important roles of contact pattern, type of memory error and the interaction of contact pattern and memory on cooperation. Although cognitive limitations may constrain the evolution of cooperation, social contact patterns can counteract some of these constraints.
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Project description:Understanding the emergence of cooperation in spatial public goods game remains a grand challenge across disciplines. In most previous studies, it is assumed that the investments of all the cooperators are identical, and often equal to 1. However, it is worth mentioning that players are diverse and heterogeneous when choosing actions in the rapidly developing modern society and researchers have shown more interest to the heterogeneity of players recently. For modeling the heterogeneous players without loss of generality, it is assumed in this work that the investment of a cooperator is a random variable with uniform distribution, the mean value of which is equal to 1. The results of extensive numerical simulations convincingly indicate that heterogeneous investments can promote cooperation. Specifically, a large value of the variance of the random variable can decrease the two critical values for the result of behavioral evolution effectively. Moreover, the larger the variance is, the better the promotion effect will be. In addition, this article has discussed the impact of heterogeneous investments when the coevolution of both strategy and investment is taken into account. Comparing the promotion effect of coevolution of strategy and investment with that of strategy imitation only, we can conclude that the coevolution of strategy and investment decreases the asymptotic fraction of cooperators by weakening the heterogeneity of investments, which further demonstrates that heterogeneous investments can promote cooperation in spatial public goods game.
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Project description:ObjectivesDetermining appropriate capitated payments has important access implications for dual-eligible Medicare Advantage (MA) members. In 2017, MA plans began receiving higher capitated payments for beneficiaries with full vs partial Medicaid when payments started being risk adjusted for level of Medicaid benefits instead of any Medicaid participation. This approach could favor MA plans in states with more generous Medicaid programs where more beneficiaries qualify for full Medicaid and thus a higher capitated payment. To understand this issue, we examined adjusted Medicare spending for dual-eligible beneficiaries across states with differing Medicaid eligibility criteria.Study designRetrospective analysis of 2007-2015 traditional Medicare data for dual-eligible beneficiaries 65 years and older.MethodsWe compared predicted per-beneficiary spending levels after adjusting for any Medicaid participation and for level of Medicaid benefits across states with varying Medicaid eligibility requirements.ResultsStates with the most generous Medicaid requirements had more dual-eligible beneficiaries with full Medicaid compared with the most restrictive states (median, 82% vs 55%). Nationally, Medicare spending levels were 1.3 times greater for full vs partial Medicaid participants (range across states, 0.8-1.7). When per-beneficiary spending was adjusted for level of Medicaid benefits, rather than any Medicaid participation, states with more generous Medicaid eligibility had larger gains in predicted spending per dual-eligible beneficiary than states with less generous Medicaid coverage (1.7% vs 1.3% increase).ConclusionsDistinguishing between partial and full Medicaid in MA payments may disproportionately increase MA payments in states that have more full Medicaid beneficiaries due to more generous Medicaid eligibility.
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