Signal weighting as an organizing principle of adaptive systems

Abstract

Current biological frameworks centred on replication, variation, and selection provide powerful explanations for evolutionary change, but do not fully explain how adaptive systems determine relevance in context or maintain coordinated behaviour across interacting components. Across diverse domains - including immune recognition, host-microbiome interactions, neural systems, and ecological regulation - adaptive behaviour depends on the integration, prioritisation, and modulation of signals through feedback.

Here, we propose signal weighting as a conceptual framework for understanding how adaptive systems assign, update, and stabilise relevance over time. Signal weighting describes the context-dependent modulation of signal influence through processes that filter, amplify, attenuate, and recursively adjust responses based on prior interactions and system state. Importantly, adaptive systems rarely function in isolation. When signal-weighting processes become coupled across interfaces between interacting systems, their dynamics can stabilise coordinated behaviours that extend beyond individual components, contributing to the emergence of higher-order adaptive units. While the underlying mechanisms differ across biological domains, similar organisational logics recur across systems that continuously adapt under changing conditions.

This logic is evident in immune pattern recognition, where signals are selectively reinforced or attenuated to maintain functional balance, and in host-microbiome systems, where immune and microbial processes reciprocally shape one another through continuous feedback across shared interfaces. In this view, adaptive organisation emerges not only through selection acting on variation, but also through the recursive stabilisation of interactions that remain coherent under perturbation.

By identifying shared weighting architectures across biological scales and substrates, signal weighting provides a conceptual bridge across fragmented adaptive literatures and offers a general organisational framework for understanding how coordinated complexity emerges, stabilises, and persists in living systems.