People in Europe responded quickly to the invasion of Ukraine with an unusually warm welcome to refugees and direct generosity in support. In stark contrast to the response to previous crises. Tony Hockley argues that this dichotomy stems from the deep-rooted human instinct for reciprocity within groups, with strong benefits but also a “dark side”. Much of the response has been in individual action, which some argue detracts from collective effort. But these actions may have beneficial spillovers, additional to the benefits of collective charity. The policy challenge will be to ensure that the motivation for action is sustained, and that the new-found generosity sets a powerful benchmark for future crises … More War & Altruism