Hysteresis Effects in Social Behavior with Parasitic Infection

TL;DR

This paper investigates how parasitic infections can influence and potentially control social behaviors at a system-wide level through hysteresis effects, using a mathematical model of population dynamics.

Contribution

It introduces a model analyzing fixed points and hysteresis in social behavior influenced by parasitic infections, highlighting conditions for infection-driven social control.

Findings

Parasitic infections can control social behavior under certain conditions.

Hysteresis effects enable persistent behavioral states influenced by infection.

Control is possible even when healthy individuals are in the majority.

Abstract

Recent work has found that the behavior of an individual can be altered when infected by a parasite. Here we explore the question: under what conditions, in principle, can a general parasitic infection control system-wide social behaviors? We analyze fixed points and hysteresis effects under the Master Equation, with transitions between two behaviors given two different subpopulations, healthy vs. parasitically-infected, within a population which is kept fixed overall. The key model choices are: (i) the internal opinion of infected humans may differ from that of the healthy population, (ii) the extent that interaction drives behavioral changes may also differ, and (iii) indirect interactions are most important. We find that the socio-configuration can be controlled by the parasitically-infected population, under some conditions, even if the healthy population is the majority and of opposite opinion.