Scaffolding minds: human collective intelligence through space, body and material symbols

Human collective intelligence (CI)-the capacity of groups to solve problems, make decisions and acquire knowledge beyond individual capabilities-is here understood as an emergent phenomenon that evolved in our lineage from a distinct trajectory of epistemic niche construction (ENC), and progressively sustained the latter. Humans systematically alter their informational landscapes in materially visible ways by creating enduring spatial and artefactual scaffolds for improved cognitive performance and social coordination. In this paper, we propose a set of criteria to define ENC and track its emergence in the archaeological record. These criteria highlight the importance of persistent, publicly accessible and evolutionarily incremental modifications that sustained behavioural coordination among individuals in space and time. We apply this framework to three major domains of material culture: the structuring of space for collective action, the culturalization of the human body and the emergence of exosomatic artefacts to store coded information. We argue that these practices did not merely externalize knowledge but progressively transformed material culture and environments into targeted epistemic infrastructures able to scaffold and amplify group-level performances characteristic of CI, thus shedding light on the evolution of human cognition and social organization. This article is part of the theme issue 'The evolution of collective intelligence'.