Biological perspective of socioeconomic inequality

This thesis explores biological implications of socioeconomic inequality via genetic and neuroimaging data. Chapter 1 demonstrates that the individual genetic differences contribute to inequalities in socioeconomic outcomes and health. Even within the same family, siblings endowed with genetically better earning potential tend to achieve better lifetime outcomes including educational qualification, income, and health. However, the genetic effects are also shown to work via environmental and behavioral pathways that can be intervened upon, with college education used as an example. Chapter 2 highlights another aspect of biological mechanisms by showing that brain anatomy and socioeconomic status are linked through regionally different degrees of genetic and environmental influences. These results emphasize a complex interplay of biological and social factors and that policy interventions should take both factors into account. Chapter 3 investigates genetic factors for income and presents that genetic associations of income reflect a part of the genetic architecture of educational attainment via phenotypically mediated effects of educational attainment on income. In particular, genetic associations of educational achievement are shown to matter for higher income only if they are also associated with better mental health. Finally, Chapter 4 introduces a new genetic data resource, which can potentially be used to study the genetic basis of socioeconomic inequality.