Using transmission chain experiments to investigate the cumulative cultural evolution of the Blombos and Diepkloof engravings

Author(s): Tylén, K; Fusaroli, R; Rojo, S; Heimann, K; Fay, N; Johannsen, NN; Riede, F; Lombard, M

Introduction: The Blombos and Diepkloof engravings from South Africa are among the earliest evidence of human symbolic behavior. Of special interest is the temporal trajectory spanning 40 thousand years from earlier simpler parallel lines to later complex cross-hatchings suggesting an adaptive development. We follow up on earlier work (Tylén et al 2020) by investigating the cumulative cultural processes giving rise to these structural changes. We seed transmission chains with early line carvings to compare experimental developments to those observed in the archaeological records.
Materials and Methods: 66 participants were divided in 11 chains of 6 generations. Each participant replicated 4 patterns by dragging, rotating and placing lines, and these patterns were presented as stimulus for the next generation. Another 61 participants then participated in a suite of 5 experiments to test the relative saliency, perceived intentionality, memorability, style, and discriminability of the patterns from different generations.
Results/discussion: While several of the measures evolve in directions similar to the archaeological records, there are also differences suggesting that transmission alone is not the mechanism by which the Blombos and Diepkloof patterns evolved.