Daring few, patient many: division of labor in decentralized foraging collectives

TL;DR

This paper models decentralized collective foraging, showing that a division of labor with explorers and foragers enables groups to make effective decisions without central control, adapting to environmental pressures.

Contribution

It introduces a simple threshold-based decision model demonstrating how decentralized groups can coordinate efficiently through division of labor without central oversight.

Findings

Larger groups need fewer explorers proportionally.

Heterogeneity peaks at intermediate ecological pressures.

Group policies emerge from simple decision rules without central control.

Abstract

How do social animals make effective decisions in the absence of a leader? While coordination can improve accuracy, it also introduces delays as information propagates through the group. In changing environments, these delays can outweigh the benefits of globally coordinated decisions, even when local interactions remain tightly organized. This raises a key question: how can groups implement efficient collective decision-making without central coordination? We address this question using a collective foraging model in which individuals share information and rewards, but each must choose whether to bear the cost of exploring or to remain idle. We show that decentralized collectives can match the performance of centrally controlled groups through a division of labor: a small, heterogeneous subset explores even when expected rewards are negative, acquiring information to enable future foraging, while a coordinated majority forages only when expected rewards are positive. Information redundancy causes the optimal number of explorers to grow sublinearly with group size, so that larger groups need proportionally fewer explorers. The heterogeneity of the group is maximized at intermediate ecological pressures, but optimal groups are homogeneous when costs or fluctuations are extreme. Crucially, these group-level policies do not require central coordination, emerging instead from agents following simple threshold-based decision rules. We thus demonstrate a mechanism through which leaderless collectives can make effective decisions under uncertainty and show how ecological pressures can drive changes in the distribution of strategies employed by the group.