The New Caledonian crow may be the only non-primate species exhibiting cumulative technological culture. Its foraging tools show clear signs of diversification and progressive refinement, and it seems likely that at least some tool-related information is passed across generations via social learning. Here, we explain how these remarkable birds can help us uncover the basic biological processes driving technological progress.

Ramsey et al. attempt to clarify methodological issues for identifying innovative behaviour. Their effort is seriously weakened by an underlying presumption that the behavior of primates is generally learned and that of non-primates is generally This presumption is based on a poor grasp of the non-primate literature and a flawed understanding of how learned behaviour is genetically assimilated.