New Caledonian (NC) crow populations have developed complex tools that show suggestive evidence of cumulative change. These tool designs, therefore, appear to be the product of cumulative technological culture (CTC). We suggest that tool-using NC crows offer highly useful data for current debates over the necessary and sufficient conditions for the emergence of CTC.

Having worked on several approaches to CO2 capture over the past decade, we have studied a great number of physical and chemical solvents as well as polymer and composite membranes. Initially, most of these materials were based upon ionic liquids (ILs), however due to challenges encountered in applying ILs to meet the demanding requirements in CO2 separation processes, there is a need to reconsider what role (if any) ILs might play in CO2 capture technologies. Ultimately, more promising and robust materials will not come from ILs themselves, but from retrosynthetic analysis and a reconsideration of which structural variables and properties are (and are not) important. The hybridization of the constituent parts into entirely new, yet seemingly familiar substances, can yield greatly improved properties and economics. This manuscript highlights recent work from our group based on lessons learned from ILs that have spurred the development of new amine solvents and polymer materials to better address the demanding process conditions and requirements of CO2 capture and related separations.

We agree with Vaesen that there is evidence for cognitive differences between humans and other primates. However, it is too early to draw firm conclusions about the uniqueness of the cognitive mechanisms underlying human tool use. Tests of causal understanding are in their infancy, as is the study of animals more distantly related to humans.