MPRG Biosocial | Biology, Social Disparities, and Development

Head: Laurel Raffington

Human development unfolds in transactions between biology, including genetics, and environments. The Max Planck Research Group Biosocial—Biology, Social Disparities, and Development examines how social disparities affect child and adolescent development to shape differential outcomes of education, health, and well-being across the life span. Our research commenced in August 2022.

Gene–environment interplay can be seen as the primary mechanism by which social inequality affects child and adolescent development, reproducing inequality over generations. We apply a biosocial perspective, which frames the biological and the social as interdependent and mutually constituting forces (see Figure 1). Outside the skin social inequality becomes measurable under the skin by influencing our proximate environments, behaviors, and interpersonal relationships (green and blue arrows). Under the skin genetic differences influence not only our biological attributes, but also our behaviors and relationships via gene–environment interplay (red arrow). Systems of social inequality impose a hierarchy on genetically influenced individual differences, which in turn affects the development of complex traits. We are motivated by four broad biosocial questions:

1. How do childhood experiences tied to social disparities, such as poverty and racism, get under the skin to shape the course of health and education inequalities across the life span?
2. What are the behavioral cascades through which genetic differences between children get out of the skin?
3. How does parenting affect child health and educational performance, controlling for genetic inheritance?
4. How do systems of social inequality impose constraints on the phenotypic expression of genetic differences between people?

We leverage recent innovations from human genomics in longitudinal cohorts and randomized trials to advance our understanding of the intergenerational transmission of social inequality. To study genetic influences on complex human traits, we use measures that combine information from many genes and gene expression modifications, including polygenic indices and epigenetic algorithms.

For example, in a recent project we examined how childhood experiences tied to socioeconomic disadvantage and racism get under the skin to shape disparities in performance on cognitive tasks. A child’s cognitive function can be harmed if their environment is stressful or lacks opportunities for learning—for example, if they regularly experience social inequalities due to their social class or race/ethnicity. Epigenetic mechanisms, including DNA methylation, are thought to be involved in the biological embedding of early life conditions. Using salivary DNA taken from a sample of 8- to 18-year-olds from central Texas, USA, we created epigenetic profiles that were originally developed in adults to predict chronic inflammation, lower cognitive function, and a faster pace of biological aging. Following preregistered analyses, we found that the epigenetic profiles of children from disadvantaged backgrounds looked worse than other children, and that children’s epigenetic profiles were associated with their performance on a range of cognitive tests (see Figure 2).

These studies provide initial evidence that epigenetic profiles are a promising tool to help us better understand how social inequalities become embedded in the body and impact the mind. The goal of this research is to help understand and reduce the effects of social inequality on well-being by identifying environmental factors and biological pathways that promote more equitable outcomes.

Adapted from Raffington et al. (2023)

Key References