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Environmental variability promotes the evolution of cooperation among humans, simulation suggests

Researchers at the University of Tsukuba have demonstrated that intensified environmental variability (EV) can promote the evolution of cooperation through simulation based on evolutionary game theory.
The findings are in the journal PLOS Complex Systems.
This result offers a new perspective for the reinterpretation of the variability selection hypothesis (VSH), which attributes improvement in human cognitive abilities to severe EV in Africa during the Middle Stone Age (MSA), as further relevant to the explanation of the evolution of sociality.
Previous scholars have widely proposed that the emergence of advanced cognitive abilities and sociality in humans originated in Africa during the MSA. However, the specific mechanisms and processes underlying this evolutionary transition lack clarification.
While the VSH is considered a leading explanation for this mystery, it has traditionally focused on the evolution of individual cognitive abilities. The current study aims to expand its explanatory scope to include the evolution of sociality and examines the influence of EV on the evolution of cooperative behavior among humans using multiagent simulation models grounded in evolutionary game theory.
The researchers developed two simple models of EV, namely, a regional and a universal variability model. The analysis was focused on the influence of changes in environmental conditions on cooperation among geographically distant groups.
The results reveal that regional variability poses new opportunities for cooperators in resource-poor areas, thereby promoting the evolution of cooperation. In contrast, the effect of universal variability was weak, which implies that EV contributes little to the evolution of cooperation without changes in interregional resource distribution.
These findings provide new perspectives for archaeological inquiry into the origins and development of social behavior during the MSA in Africa. In addition, they offer potential insights into the mechanisms through which EVs and large-scale crises shape cooperative behavior in modern society.
More information: Masaaki Inaba et al, Environmental variability promotes the evolution of cooperation among geographically dispersed groups on dynamic networks, PLOS Complex Systems (2025).
Provided by University of Tsukuba