Classifying Emergence in Robot Swarms: An Observer-Dependent Approach

TL;DR

This paper proposes an observer-dependent framework to rigorously define and classify emergence in robot swarms, emphasizing the subjective role of perception and the importance of the generative process behind swarm behaviors.

Contribution

It introduces a formal approach separating observable states from latent ones, clarifying the subjective nature of emergence and swarm definitions based on the observer's perspective.

Findings

Highlights the role of the observer's vantage point in defining emergence.

Provides a framework to compare different definitions of swarms and emergence.

Distinguishes between multi-robot systems and true swarms.

Abstract

Emergence and swarms are widely discussed topics, yet no consensus exists on their formal definitions. This lack of agreement makes it difficult not only for new researchers to grasp these concepts, but also for experts who may use the same terms to mean different things. Many attempts have been made to objectively define 'swarm' or 'emergence,' with recent work highlighting the role of the external observer. Still, several researchers argue that once an observer's vantage point (e.g., scope, resolution, context) is established, the terms can be made objective or measured quantitatively. In this note, we propose a framework to discuss these ideas rigorously by separating externally observable states from latent, unobservable ones. This allows us to compare and contrast existing definitions of swarms and emergence on common ground. We argue that these concepts are ultimately subjective-shaped less by the system itself than by the perception and tacit knowledge of the observer. Specifically, we suggest that a 'swarm' is not defined by its group behavior alone, but by the process generating that behavior. Our broader goal is to support the design and deployment of robotic swarm systems, highlighting the critical distinction between multi-robot systems and true swarms.