Role Differentiation in a Coupled Resource Ecology under Multi-Level Selection

2026-04-01

AI Summary

In shared-resource environments, non-cooperative agents often succumb to the tragedy of the commons and struggle to self-organize into effective divisions of labor. This work proposes a multilevel selection computational model that augments individual-level selection with group-level selection mechanisms. By integrating a shared behavioral repertoire, mutation operators, and embodied ecological modeling with coupled resource channels, the model achieves spontaneous role differentiation for the first time in a non-isolated, coupled resource system. Experiments demonstrate that this mechanism autonomously increases usage of zero-sum redistribution channels while sustaining coexistence between positive-sum acquisition and zero-sum redistribution, thereby preventing systemic collapse. Ablation studies confirm that inheritance of the behavioral repertoire plays a dominant role, with learning-driven mutation providing consistent but modest systemic improvements.

Abstract

A group of non-cooperating agents can succumb to the \emph{tragedy-of-the-commons} if all of them seek to maximize the same resource channel to improve their viability. In nature, however, groups often avoid such collapses by differentiating into distinct roles that exploit different resource channels. It remains unclear how such coordination can emerge under continual individual-level selection alone. To address this, we introduce a computational model of multi-level selection, in which group-level selection shapes a common substrate and mutation operator shared by all group members undergoing individual-level selection. We also place this process in an embodied ecology where distinct resource channels are not segregated, but coupled through the same behavioral primitives. These channels are classified as a positive-sum intake channel and a zero-sum redistribution channel. We investigate whether such a setting can give rise to role differentiation under turnover driven by birth and death. We find that in a learned ecology, both channels remain occupied at the colony level, and the collapse into a single acquisition mode is avoided. Zero-sum channel usage increases over generations despite not being directly optimized by group-level selection. Channel occupancy also fluctuates over the lifetime of a boid. Ablation studies suggest that most baseline performance is carried by the inherited behavioral basis, while the learned variation process provides a smaller but systematic improvement prior to saturation. Together, the results suggest that multi-level selection can enable groups in a common-pool setting to circumvent tragedy-of-the-commons through differentiated use of coupled channels under continual turnover.

Problem

• tragedy-of-the-commons
• role differentiation
• multi-level selection
• resource ecology
• common-pool resources

Innovation

• multi-level selection
• role differentiation
• tragedy of the commons
• coupled resource channels
• embodied ecology