Does scarcity induce hostility? An experimental investigation of common-pool resources

Climate change is leading to an increased scarcity of resources such as freshwater, energy, arable land and wildlife. This is perceived as a major security threat. However, the literature remains unclear on whether scarcity mitigates or exacerbates conflict. We design a novel laboratory experiment to investigate hostile behavior under scarcity. Participants interact repeatedly in a dynamic common-pool resource (CPR) and a joy-of-destruction game. The experiment distinguishes between two types of scarcity: Endogenous scarcity in the form of a deliberate human choice to overexploit resources and exogenous scarcity in the form of adverse environmental conditions. Our results show that endogenous scarcity exacerbates hostility. We trace this to participants being guided by negative reciprocity while finding no support for inequality aversion. The results indicate that to avoid hostility, policy makers will have to reduce human-induced scarcity. However, our results also show that exogenous scarcity mitigates hostility. This is in line with a vast body of literature from psychology, anthropology and biology finding increased levels of cooperation for all forms of life under environmental distress. It suggests that managing perceptions around increasing scarcities could be a second potential avenue for policy action. • Human-induced scarcity increases hostility between resource users. • This can be attributed to negative reciprocity. • Environmental scarcity reduces hostility between resource users. • This can be attributed to a social norm of cooperation. • Cause of scarcity is decisive for its effect on conflict.