Inheritance of wealth as human kin investment

Like many other animals, humans appear to have evolved to invest time and energy in their relatives in order to maximize inclusive fitness. Inheritance of material wealth may be a uniquely human form of kin investment. If fitness-maximizing dispositions do influence will-makers, beneficiaries may be favored according to their relatedness and reproductive value. An analysis of 1000 probated wills showed that this was the case. Close relatives were favored over distant kin, as were kin of higher reproductive value. Wealthier decedents favored male kin, while poorer decedents favored females. This pattern might reflect a facultative shifting of resources toward males when the family's resources are sufficient to ensure reproductive competitiveness, and toward the safer option of females when resources are less abundant. The results support the possibility that fitness-maximizing dispositions do influence will-makers. It is likely that such dispositions are flexible and responsive to the physical and social environment.     

Property and wealth inequality as cultural niche construction

In contrast to other approaches, evolutionary perspectives on understanding the power and wealth inequalities in human societies view wealth and power not as ends in themselves but as proximate goals that contribute to the ultimate Darwinian goal of achieving reproductive success. The most successful means of achieving it in specific times and places depend on local conditions and these have changed in the course of human history, to such an extent that strategies focused on the maintenance and increase of wealth can even be more successful in reproductive terms than strategies directed at maximizing reproductive success in the short term. This paper argues that a major factor leading to such changes is a shift in the nature of inter-generational wealth transfers from relatively intangible to material property resources and the opportunities these provided for massively increased inequality. This shift can be seen as a process of niche construction related to the increasing importance of fixed and defensible resources in many societies after the end of the last Ice Age. It is suggested that, despite problems of inference, the evidence of the archaeological record can be used to throw light on these processes in specific places and times.     

Social benefits of luxury brands as costly signals of wealth and status

Drawing from costly signaling theory, we predicted that luxury consumption enhances status and produces benefits in social interactions. Across seven experiments, displays of luxury — manipulated through brand labels on clothes — elicited different kinds of preferential treatment, which even resulted in financial benefits to people who engaged in conspicuous consumption. Furthermore, we tested preconditions in which the beneficial consequences of conspicuous consumption may arise and determined the proximate mechanisms underlying them. The present data suggest that luxury consumption can be a profitable social strategy because conspicuous displays of luxury qualify as a costly signaling trait that elicits status-dependent favorable treatment in human social interactions.     

How wealth accumulation can promote cooperation

Explaining the emergence and stability of cooperation has been a central challenge in biology, economics and sociology. Unfortunately, the mechanisms known to promote it either require elaborate strategies or hold only under restrictive conditions. Here, we report the emergence, survival, and frequent domination of cooperation in a world characterized by selfishness and a strong temptation to defect, when individuals can accumulate wealth. In particular, we study games with local adaptation such as the prisoner's dilemma, to which we add heterogeneity in payoffs. In our model, agents accumulate wealth and invest some of it in their interactions. The larger the investment, the more can potentially be gained or lost, so that present gains affect future payoffs. We find that cooperation survives for a far wider range of parameters than without wealth accumulation and, even more strikingly, that it often dominates defection. This is in stark contrast to the traditional evolutionary prisoner's dilemma in particular, in which cooperation rarely survives and almost never thrives. With the inequality we introduce, on the contrary, cooperators do better than defectors, even without any strategic behavior or exogenously imposed strategies. These results have important consequences for our understanding of the type of social and economic arrangements that are optimal and efficient.     

How strategy environment and wealth shape altruistic behaviour: cooperation rules affecting wealth distribution in dynamic networks

Societies rely on individual contributions to sustain public goods that benefit the entire community. Several mechanisms, that specify how individuals change their decisions based on past experiences, have been proposed to explain how altruists are not outcompeted by selfish counterparts. A key aspect of such strategy updates involves a comparison of an individual''s latest payoff with that of a random neighbour. In reality, both the economic and social milieu often shapes cooperative behaviour. We propose a new decision heuristic, where the propensity of an individual to cooperate depends on the local strategy environment in which she is embedded as well as her wealth relative to that of her neighbours. Our decision-making model allows cooperation to be sustained and also explains the results of recent experiments on social dilemmas in dynamic networks. Final cooperation levels depend only on the extent to which the strategy environment influences altruistic behaviour but are largely unaffected by network restructuring. However, the extent of wealth inequality in the community is affected by a subtle interplay between the environmental influence on a person''s decision to contribute and the likelihood of reshaping social ties, with wealth-inequality levels rising with increasing likelihood of network restructuring in some situations.     

Natural selection on male wealth in humans

Although genomic studies suggest that natural selection in humans is ongoing, the strength of selection acting on particular characteristics in human populations has rarely been measured. Positive selection on male wealth appears to be a recurrent feature of human agrarian and pastoralist societies, and there is some evidence of it in industrial populations, too. Here we investigate the strength of selection on male wealth, first in contemporary Britain using data from the National Child Development Study and then across seven other varied human societies. The British data show positive selection on male income driven by increased childlessness among low-income men but a negative association between personal income and reproductive success for women. Across cultures, selection gradients for male wealth are weakest in industrial countries and strongest in subsistence societies with extensive polygyny. Even the weakest selection gradients observed for male wealth in humans are as strong as or stronger than selection gradients reported from field studies of other species. Thus, selection on male wealth in contemporary humans appears to be ubiquitous and substantial in strength.     

Health and wealth in the Roman Empire

Ancient Rome was the largest and most populous empire of its time, and the largest pre-industrial state in European history. Recent though not universally accepted research suggests that at least for the most populous central periods of its history standard of living was also rather higher than before or after. To trace whether this is also reflected in Roman biological standard of living, we present the first large and more or less comprehensive dataset, based on skeletal data for some 10,000 individuals, covering all periods of Roman history, and all regions (even if inevitably unequally). We discuss both the methodologies that we developed and the historical results. Instead of reconstructing heights from the long bones assuming fixed body proportions or from one individual long bone, we apply exploratory factor analysis and calculate factor scores for 50-year periods. Our measure of the biological standard of living declined during the last two centuries B.C. and started to improve again, slowly at first, from the second century A.D. It correlated negatively with population, but also with other aspects of standard of living such as wages or diets.