Figure 1

Symbolic Modeling of tool-making action sequences. (A) Oldowan (top) and Acheulean (bottom) action sequences were coded using 7 event codes (circled letters, see Materials & Methods). Products illustrated to the right, individual depicted is the first author. (B, Left) Spatial trajectory of the hammer stone during toolmaking. The X–Y plane is aligned with the plane of the percussion strike hand-arm movements. The core is centred at approximately 80 cm, − 70 cm, 0 cm. (B, Right) Distance of the hammerstone from the centre of the core. Target change movements are coded in red. Percussion strike trajectories are in dark blue, light percussion movements (here for platform preparation) are in light blue. Below, the black bars indicate the corresponding timing and duration of the ethogram.