The prospect of rising in rank is key to long-term stability in Tibetan macaque society

The ecology of wealth inequality in animal societies

Individuals vary in their access to resources, social connections and phenotypic traits, and a central goal of evolutionary biology is to understand how this variation arises and influences fitness. Parallel research on humans has focused on the causes and consequences of variation in material possessions, opportunity and health. Central to both fields of study is that unequal distribution of wealth is an important component of social structure that drives variation in relevant outcomes. Here, we advance a research framework and agenda for studying wealth inequality within an ecological and evolutionary context. This ecology of inequality approach presents the opportunity to reintegrate key evolutionary concepts as different dimensions of the link between wealth and fitness by (i) developing measures of wealth and inequality as taxonomically broad features of societies, (ii) considering how feedback loops link inequality to individual and societal outcomes, (iii) exploring the ecological and evolutionary underpinnings of what makes some societies more unequal than others, and (iv) studying the long-term dynamics of inequality as a central component of social evolution. We hope that this framework will facilitate a cohesive understanding of inequality as a widespread biological phenomenon and clarify the role of social systems as central to evolutionary biology.

Information About Inequality of Opportunity Increases Downward Mobility Perceptions: A Population-Wide Randomized Survey Experiment

Existing evidence which is primarily based on cross-sectional and observational data suggests that perceptions of doing worse or better than parents might be more important for various life outcomes than the conventional measures of mobility based on the objective indicators of socioeconomic position. In 2021, we commissioned a nationally representative survey in Georgia which included a population-wide randomized survey experiment. We confirmed the association between, on the one hand, perceived social mobility and, on the other hand, physical and mental health, satisfaction with life, and the perceived state of affairs in the country. More importantly, the experimental design allowed us to conclude that the perception of being downwardly mobile was causally determined by a short message shared with individuals that equality of opportunity in their country was low. Those who were given information that children's socioeconomic position was strongly linked to their parents' socioeconomic position were seven percentage points more likely than individuals in the control group to perceive themselves as being downwardly mobile. We extrapolate these findings to the broader context and argue that the messages about (in)equality of opportunity which individuals receive in their everyday lives might also shape their perceptions of social mobility in other countries.