The evolution of symbolic artefacts: How function shapes form

Despite the indisputable significance of human symbolic cognition and behavior, we still lack a detailed understanding of the mechanisms by which such capacities evolved during the Paleolithic. An important source of evidence is constituted by archaeological findings of intentional markings left on rock and bone surfaces, but these are often opaque with respect to their original meaning and function. Here we present experimental work that systematically addresses the relation between properties of intentional markings and their cognitive implications to support inferences about their past functions. Participants reproduced engraved markings dating to c. 100.000 years ago from the South African Blombos and Diepkloof sites in three conditions of cultural transmission: as part of an aesthetic, identity marking, and communicative activity. Their reproductions were then used as stimuli in a suite of five perceptual experiments to investigate differences in their cognitive implications over time and explore similarities with the archaeological record.