naa a22 4500 528784889 20180924065517.0 cr unu---uuuuu 180924e20110624xx s 000 0 eng 10.3929/ethz-b-000037916 doi 10.1371/journal.pone.0020851 doi (ETHRESEARCH)oai:www.research-collection.ethz.ch:20.500.11850/37916 Johnson Dominic D.P. Fortune Favours the Bold: An Agent-Based Model Reveals Adaptive Advantages of Overconfidence in War [Elektronische Daten] [Dominic D.P. Johnson, Nils B. Weidmann, Lars-Erik Cederman] PLoS ONE Open access ethresearch Overconfidence has long been considered a cause of war. Like other decision-making biases, overconfidence seems detrimental because it increases the frequency and costs of fighting. However, evolutionary biologists have proposed that overconfidence may also confer adaptive advantages: increasing ambition, resolve, persistence, bluffing opponents, and winning net payoffs from risky opportunities despite occasional failures. We report the results of an agent-based model of inter-state conflict, which allows us to evaluate the performance of different strategies in competition with each other. Counter-intuitively, we find that overconfident states predominate in the population at the expense of unbiased or underconfident states. Overconfident states win because: (1) they are more likely to accumulate resources from frequent attempts at conquest; (2) they are more likely to gang up on weak states, forcing victims to split their defences; and (3) when the decision threshold for attacking requires an overwhelming asymmetry of power, unbiased and underconfident states shirk many conflicts they are actually likely to win. These "adaptive advantages” of overconfidence may, via selection effects, learning, or evolved psychology, have spread and become entrenched among modern states, organizations and decision-makers. This would help to explain the frequent association of overconfidence and war, even if it no longer brings benefits today. Creative Commons Attribution 3.0 Unported http://creativecommons.org/licenses/by/3.0 ethresearch Weidmann Nils B. joint author Cederman Lars-Erik joint author PLoS ONE Lawrence, KS, USA : Public Library of Science 6 (6), p. e20851 1932-6203 http://hdl.handle.net/20.500.11850/37916 text/html WWW-Backlink auf das Repository (Open access) 1 Journal Article ethresearch ETHRESEARCH 856 40 http://hdl.handle.net/20.500.11850/37916 text/html WWW-Backlink auf das Repository (Open access) ETHRESEARCH 100 1- Johnson Dominic D.P. ETHRESEARCH 700 1- Weidmann Nils B. joint author ETHRESEARCH 700 1- Cederman Lars-Erik joint author ETHRESEARCH 773 0- PLoS ONE Lawrence, KS, USA : Public Library of Science 6 (6), p. e20851 1932-6203 BK010053 XK010053 XK010000 ETHRESEARCH ETHRESEARCH ETHRESEARCH Journal Article Open access