Individual variation evades the Prisoner's Dilemma

BACKGROUND: The Prisoner's Dilemma (PD) is a widely used paradigm to study cooperation in evolutionary biology, as well as in fields as diverse as moral philosophy, sociology, economics and politics. Players are typically assumed to have fixed payoffs for adopting certain strategies, which depend only on the strategy played by the opponent. However, fixed payoffs are not realistic in nature. Utility functions and the associated payoffs from pursuing certain strategies vary among members of a population with numerous factors. In biology such factors include size, age, social status and expected life span; in economics they include socio-economic status, personal preference and past experience; and in politics they include ideology, political interests and public support. Thus, no outcome is identical for any two different players. RESULTS: We show that relaxing the assumption of fixed payoffs leads to frequent violations of the payoff structure required for a Prisoner's Dilemma. With variance twice the payoff interval in a linear PD matrix, for example, only 16% of matrices are valid. CONCLUSIONS: A single player lacking a valid PD matrix destroys the conditions for a Prisoner's Dilemma, so between any two players, PD games themselves are fewer still (3% in this case). This may explain why the Prisoner's Dilemma has hardly been found in nature, despite the fact that it has served as a ubiquitous (and still instructive) model in studies of the evolution of cooperation

Host candidate gene polymorphisms and clearance of drug-resistant Plasmodium falciparum parasites

Resistance to anti-malarial drugs is a widespread problem for control programmes for this devastating disease. Molecular tests are available for many anti-malarial drugs and are useful tools for the surveillance of drug resistance. However, the correlation of treatment outcome and molecular tests with particular parasite markers is not perfect, due in part to individuals who are able to clear genotypically drug-resistant parasites. This study aimed to identify molecular markers in the human genome that correlate with the clearance of malaria parasites after drug treatment, despite the drug resistance profile of the protozoan as predicted by molecular approaches

Genetic polymorphisms of the RAS-cytokine pathway and chronic kidney disease

Chronic kidney disease (CKD) in children is irreversible. It is associated with renal failure progression and atherosclerotic cardiovascular (CV) abnormalities. Nearly 60% of children with CKD are affected since birth with congenital or inherited kidney disorders. Preliminary evidence primarily from adult CKD studies indicates common genetic risk factors for CKD and atherosclerotic CV disease. Although multiple physiologic pathways share common genes for CKD and CV disease, substantial evidence supports our attention to the renin angiotensin system (RAS) and the interlinked inflammatory cascade because they modulate the progressions of renal and CV disease. Gene polymorphisms in the RAS-cytokine pathway, through altered gene expression of inflammatory cytokines, are potential factors that modulate the rate of CKD progression and CV abnormalities in patients with CKD. For studying such hypotheses, the cooperative efforts among scientific groups and the availability of robust and affordable technologies to genotype thousands of single nucleotide polymorphisms (SNPs) across the genome make genome-wide association studies an attractive paradigm for studying polygenic diseases such as CKD. Although attractive, such studies should be interpreted carefully, with a fundamental understanding of their potential weaknesses. Nevertheless, whole-genome association studies for diabetic nephropathy and future studies pertaining to other types of CKD will offer further insight for the development of targeted interventions to treat CKD and associated atherosclerotic CV abnormalities in the pediatric CKD population

Dealing with uncertainty and cognitive biases in international politics

Review of War and Chance: Assessing Uncertainty in International Politics By Jeffrey Friedman, New York, NY: Oxford University Press, 2019. £32.99. Reviewed by Dominic Johnson Response by Jeffrey Friedman Review of Strategic Instincts: The Adaptive Advantages of Cognitive Biases in International Politics By Dominic Johnson, Princeton, NJ: Princeton University Press, 2020. $32.00/£28.00 Reviewed by Jeffrey Friedman Response by Dominic Johnso

Science and religion around the world: compatibility between belief systems predicts increased well-being

Previous research, conducted mainly in Western societies, indicates that religious/spiritual (R/S) and pro-science belief systems each relate positively to the well-being of those who hold them, but are perceived as being highly incompatible with each other. This perception would presumably undermine one’s ability to benefit fully from both systems, leading to the research questions we explore here: does the perceived incompatibility between religion and science vary across cultural groups, and is the level of incompatibility itself related to group member well-being? Our data set included 55,230 participants from 54 countries, organized for analytical purposes into 13 global regions and 11 belief groups. We found that perceived incompatibility between R/S and pro-science beliefs was indeed characteristic of the West, but that it was not the norm cross-culturally. We also found that higher levels of belief system compatibility related positively to well-being, and especially to the strength of positive associations between well-being and each type of belief system. That is, in regions and belief groups that perceived higher compatibility, well-being’s positive relationships with R/S and pro-science beliefs were both also higher. We speculate about compatibility’s potential causal effects on these relationships, noting that as compatibility increases, so does the possibility of benefiting from one system without forgoing the benefits of the other

Long-term resource variation and group size: A large-sample field test of the Resource Dispersion Hypothesis

<p>Abstract</p> <p>Background</p> <p>The Resource Dispersion Hypothesis (RDH) proposes a mechanism for the passive formation of social groups where resources are dispersed, even in the absence of any benefits of group living <it>per se.</it> Despite supportive modelling, it lacks empirical testing. The RDH predicts that, rather than Territory Size (TS) increasing monotonically with Group Size (GS) to account for increasing metabolic needs, TS is constrained by the dispersion of resource patches, whereas GS is independently limited by their richness. We conducted multiple-year tests of these predictions using data from the long-term study of badgers <it>Meles meles</it> in Wytham Woods, England. The study has long failed to identify direct benefits from group living and, consequently, alternative explanations for their large group sizes have been sought.</p> <p>Results</p> <p>TS was not consistently related to resource dispersion, nor was GS consistently related to resource richness. Results differed according to data groupings and whether territories were mapped using minimum convex polygons or traditional methods. Habitats differed significantly in resource availability, but there was also evidence that food resources may be spatially aggregated within habitat types as well as between them.</p> <p>Conclusions</p> <p>This is, we believe, the largest ever test of the RDH and builds on the long-term project that initiated part of the thinking behind the hypothesis. Support for predictions were mixed and depended on year and the method used to map territory borders. We suggest that within-habitat patchiness, as well as model assumptions, should be further investigated for improved tests of the RDH in the future.</p

Is Evil Good for Religion? The Link between Supernatural Evil and Religious Commitment

“The devil made me do it” is a familiar cliché often used to justify a bad decision. However, are beliefs in a devil or other evil supernatural beings actually beneficial for religion? Building upon Stark and Bainbridge (1987) and elements of the supernatural punishment hypothesis, this study proposes and tests the hypothesis that a positive relationship exists between the belief in supernatural evil and religious commitment. Data from 2007 Baylor Religion Survey reveal a strong positive correlation between the belief in supernatural evil and four measures of religious commitment: church attendance, religious perception, tithing, and faith sharing. This study not only contributes to a long discussion of religious commitment, but it also has implications for the growing literature on god images and the supernatural punishment hypothesis