Mutual aid: When does resource scarcity favour group cooperation?

International audienceUnderstanding the origins, conditions, advantages and limitations of cooperation in natural and social systems has motivated many investigations in the biological and social sciences. To investigate individual cooperative behaviour in the face of temporal and spatial heterogeneity of resources we considered a definition of cooperation at the same ontological level as competition. We define a cooperative behaviour when an agent acts upon one or more resource(s) with a beneficial result in at least one resource for a recipient of this action, and with a selection process for this behaviour on the side of the acting agent. We implemented an agent-based model that represents the interactions of agents through their use of resources. With this model, we illustrated how scarcity of resources in space and time might create situations where cooperative behaviour is beneficial to individuals or to egalitarian groups. Simulations highlighted that temporal scarcity as spatial scarcity of the resource procures advantages to egalitarian groups over competitive individuals. Additionally, the factors favouring equity among agents for the access to the resource promote the success of cooperation. Simulations also showed the limitations imposed by group size on cooperation in the context of a common-pool management system. The possibility of using indicators of (spatio-temporal) resource variability to characterize the potential for the emergence of cooperation is an interesting research objective for future work.Highlights:• Definition of cooperation based on resource is compatible with the one of competition.• The success of cooperation depending on the heterogeneity of resource can be explored.• Temporal heterogeneity may favor cooperation more than spatial heterogeneity.• The conditions favoring equity of resource access for cooperators favor cooperation.• Group size may be a limiting factor in cooperative common-pool management systems