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PDF (1.70 MB)
Pages 226-233
First published 2 July 2012

Coevolutionary Dynamics between Roles and Social Sensitivity in an Extended Minority Game

Keita Nishimoto, Ivan Tanev, Katsunori Shimohara, Reiji Suzuki, Takaya Arita


The social brain hypothesis suggests that humans evolved larger brains and intelligence as adaptations to an increasingly complex social environment. We believe that social role division is a key factor in the evolution of social intelligence. To examine the role of this factor, we extend Challet and Zhang's Minority Game by adding a pre-decision communication stage and using a continuous strategy space instead of a binary one, and develop an evolutionary model based on this game. The evolutionary simulations demonstrate that the system alternates between two states: one with homogeneous social behavior and the other with heterogeneous behavior. We observe differentiation of social roles in the latter state: we find a "pivotal agent" that tends to adopt low-risk, low payoff strategies but determines which strategy will be in the minority and which in the majority, and we find "risk taker" that tend to adopt high-risk, high pay-off strategies. Using social sensitivity as a measure of social intelligence, we show that the level of social sensitivity correlates with the social roles, and is also a major factor in the mechanisms by which social roles switch.