Given the constraints of human evolved psychology (such as our memory and oral communication capacities), many forms of cooperation necessary for large groups to evolve and persist would have been impossible.
Current theory in the cognitive sciences can explain most of the cooperation observed in the small-scale societies that characterised most of our species’ evolutionary history. These evolved capacities, however, would have been insufficient to sustain the form and scale of cooperation in large-scale societies. The evolution of social complexity required an extension of human cognitive capacities in ways that could not have occurred solely through genetic selection. Large-scale human societies require individuals routinely to bear costs for the benefit of genetically unrelated individuals in a wide variety of ways, ranging from the remittance of tribute or tax to more extreme forms of self-sacrifice as cannon fodder on the battlefield. Explaining the evolution of cooperation in large societies presents a theoretical puzzle because co-operators in a population are vulnerable to exploitation by free-riders.
Efforts to account for the emergence of large-scale cooperative human societies have focused on a range of cultural advances, from the advent of agriculture to the emergence of new forms of political regulation and social identification. A number of these cultural adaptations have been proposed to overcome the shortcomings of our innate psychological tools but little attention has been accorded to the role of writing and recordkeeping in the evolution of cooperation in large-scale societies, the main focus of the current study.
The behavioural innovation of literacy is one of the most consequential changes that humans experienced during the Holocene. Recent insights and evidence garnered here from anthropology, behavioural economics, palaeography, grammatology, and evolutionary psychology suggest that writing and recordkeeping allowed humans to solve the problem of cooperation in ethnically diverse, ultrasocial polities by facilitating five processes vital for the effective cooperation among strangers: reciprocity, reputation formation and maintenance, norm enforcement, identification with imagined communities, and the extension of empathy to anonymous others.
Writing and recordkeeping support systems of reciprocal exchange by facilitating the tracking of heterogeneous interactions that would otherwise have been impossible to track and remember. They provide a durable record of people’s past behaviour and reputational status. They promote the standardization and maintenance of social norms and associated moral punishments in large populations. They expedite the creation of increasingly large and salient group identities. Finally, literate systems facilitate empathy towards strangers. These varied functions of literacy played a crucial and hitherto neglected role in the evolution of social complexity.