Determining hominid handedness in Lithic Debitage: A review of current methodologies

Handedness is inextricably linked to brain lateralization and language in humans, and identifying handedness in the paleo-archaeological record is important for understanding hominid cognitive evolution. This study reports on experiments for identifying knapper handedness in lithic debitage using three previously established methods: Toth (1985), Rugg and Mullane (2001), and Bargalló and Mosquera (2013). A blind study was conducted on lithic debitage (n = 631) from Acheulean handaxes (n = 10) created by right- and left-handed subjects. Blinded handedness predictions for flakes were compared to their true handedness in order to assess each method’s reliability. In order to test replicability, multiple observers classified a sample of flakes and inter-observer greement was assessed. None of the methods were better than chance in predictive accuracy, and there were significant issues with interobserver agreement. This study suggests that identifying knapper handedness in lithic debitage is extremely difficult, but also that some existing methodological issues may have simple solutions; suggestions for future research on this topic are provided.