The role of know-how copying in and beyond social tinkering.

Stage 2 of Chater and Christiansen's (henceforth CC) model involves the ability to copy. Our comment concerns not the order of copying in CC's model, but their time estimate of its origins. CC treat copying as present in apes and implied by early stone tools, and hence (presumably) had by the last common ancestor. Here we argue for a later onset.