NEWS AND VIEWS 22 April 2026 Real-world data reveal that cooperation continually falls and rebounds. Motivation to cooperate must therefore be actively renewed rather than assumed to sustain itself. By Jiabin Wu Jiabin Wu is in the Department of Economics, University of Oregon, Eugene, Oregon 97401, USA. Why do humans cooperate with each other? This question has long been of interest to social and behavioural scientists because social dilemmas create a conflict between individual material incentives (such as financial gain) and collective efficiency. Cooperation produces socially desirable outcomes, but withdrawal from cooperation (known as defection) is often rational for people or groups acting in their own self-interest. Even so, human societies have repeatedly shown a striking capacity to sustain cooperation in practice — although achieving cooperation does not mean that it is permanent. Writing in Nature , Sabin et al .…