The dual foundations of political ideology are ubiquitous across human social life

The contemporary political landscape is often represented by a single dimension of conflict: authority, hierarchy, and tradition on the right versus greater freedom, equality, and systemic change on the left. Here, we argue that politics comprises not one, but two dimensions. Moreover, these two dimensions are not unique to modern nations, but reflect a psychology shaped by two evolutionary trade-offs which we call the ‘dual foundations’ of politics and argue are inherent to human social life. One foundation concerns the trade-off between cooperation and competition and gives rise to contestation over levels of inequality and provision of public goods. The other foundation concerns the trade-off between autonomy and conformity, leading to contestation over the extent of social control. Drawing on anthropological, psychological, and historiographical evidence, we argue that these dual foundations are contested across the diversity of human lifeways and represent two cross-culturally ubiquitous dimensions of ideology. As such, the dual foundations provide a common evolutionary framework for studying human politics across geography, history, subsistence styles, levels of social organisation, and academic disciplines. We end by outlining how quantitative approaches to studying the dual foundations beyond industrialised nations can advance research on both the anthropology and psychology of political ideology.