ECMTB 2024

Abstract

Political decisions are the epitome of how many aspects of our lives are determined by collective decision-making. However, active participation in collective decision-making is often highly variable, with many individuals temporarily abstaining from voting in the face of uncertainty. Whilst memory and noise have been found to aid consensus formation, the role of neutrality in collective decision-making is not well understood, and the level of individual behavioural complexity required for the emergence of group consensus is not well-characterised. In this talk, I will show that symmetric autonomous systems with neutral intermediate states, such as voters of a two-party system who can abstain, present only two possible dynamical pathways for consensus switching. I will also show how experiments with human participants helped us verify our predictions. The typical pathway observed in our experimental data corresponds to an increase in the number of abstentions as the system transitions from one state of consensus to the other, suggesting that they play a critical role in facilitating consensus change by reducing the effective population size, making it more susceptible to fluctuations, as opposed to what has been previously believed. Our findings provide a parsimonious explanation of consensus formation and change, giving insight into distributed decision-making protocols in animal and human collectives and suggesting efficient solutions to automated collective decision-making problems.

References:

[1] A. Sontag, T. Rogers and C. A. Yates, Consensus Formation And Change Are Enhanced By Neutrality, (Under Review) 2025.

Andrei Sontag

Research Fellow

My research interests include stochastic processes applied to complex systems with a focus on ecology, evolution, financial markets and collective behaviour.