Social information use and the evolution of unresponsiveness in collective systems
Couzin, Iain D.
Levin, Simon A.
© 2014 The Author(s) Published by the Royal Society. All rights reserved.
Reason for embargo
Animal groups in nature often display an enhanced collective information-processing capacity. It has been speculated that natural selection will tune this response to be optimal, ensuring that the group is reactive while also being robust to noise. Here, we show that this is unlikely to be the case. By using a simple model of decision-making in a dynamic environment, we find that when individuals behave rationally and are subject to selection based on their accuracy, optimality of collective decision-making is not attained. Instead, individuals overly rely on social information and evolve to be too readily influenced by their neighbours. This is due to a classic evolutionary conflict between individual and collective interest. The result is a sub-optimal system that is poised on the cusp of total unresponsiveness. Individuals in the evolved group exhibit delayed reactions to changes in the environment, before responding with rapid, socially reinforced transitions, reminiscent of familiar human and animal social systems (markets, stampedes, fashions, etc.). Our results demonstrate that behaviour of this type may not be pathological, but instead could represent an evolutionary attractor for such collective systems.
Army Research Office
National Science Foundation
Office of Naval Research
Human Frontier Science Project
Fondation Sciences Mathematiques de Paris (FSMP)
French National Research Agency
Vol. 12 (103), article 20140893
Place of publication