The Manipulative Complexity of Lower Paleolithic Stone Toolmaking
(A) Cumulative variability explained by principle components (from the full set of the hand configuration time series data) for toolmaking (Oldowan - circle, Acheulean - square) and control tasks (widget sorting - downward pointing triangle, box stacking - upward pointing triangle). Small object manipulation is clearly less complex than toolmaking (greater variance explained by PC 1 and above). Box stacking is much more comparable, but is still distinguished from PCs 6, 7,8 and onwards. (B) Comparison of using the full time series versus the event-triggered (percussion events) to calculate the PCA variance explained demonstrate that they are very similar. Blue circles are the corresponding variance explained of the PCA extracted from Oldowan trials (red squares Acheulean trials). (C,D) Schematic of the object manipulations performed in the control task. (C) individual nut-sized widgets were picked from a box and placed in alternating adjacent boxes. (D) Boxes (styrofoam, top open) were stacked upon each other and then unstacked again.