The link between gender inequality and the distribution of brain regions’ relative sizes across the lifespan and the world

Evidence is emerging that the socioeconomic environment in general, and gender inequality in particular, can be a shaping force on brain structure. However, our understanding of the nature of this influence throughout the lifespan is often limited because most current data sets are geographically and demographically narrow, making it unclear whether results hold across distinct world populations. Here we analyse, for the first time, data from an online MRI analysis platform comprising 13277 subjects from 52 countries and the five continents, across ages that range from childhood to late life. We examined how gender inequality, jointly examined with economic inequality, relates to differences in brain grey matter between males and females. We found that the association between female-male brain differences and gender inequality increases with age, suggesting a cumulative effect of gender inequality throughout life. Further, by considering additional variables that are specifically related to the economy, we found that this effect was, as per current data, dominated by the economic aspects of inequality.