The spatial ultimatum game revisited

Jaime Iranzo (1, 2) , Javier Román , Angel Sánchez (2, 3)

1 CAB - Centro de Astrobiologia [Madrid]
2 University of Zaragoza - Universidad de Zaragoza [Zaragoza]
3 ICMAT - Instituto de Ciencias Matemàticas [Madrid]

We revisit the issue of the emergence of fair behavior in the framework of the spatial Ultimatum game, adding many important results and insights to the pioneering work by Page [Proc. R. Soc. Lond. B 267, 2177 (2000)], who showed in a specific example that on a two-dimensional setup evolution may lead to strategies with some degree of fairness. Within this spatial framework, we carry out a thorough simulation study and show that the emergence of altruism is a very generic phenomenon whose details depend on the dynamics considered. A very frequent feature is the spontaneous emergence and fixation of quasiempathetic individuals, whose offers are very close to their acceptance thresholds. We present analytical arguments that allow an understanding of our results and give insights on the manner in which local effects in evolution may lead to such non-rational or apparently maladaptive behaviours.

Mots clés: Evolution; Fairness; Rationality; Game theory; Spatial dynamics

Domaines: Sciences du Vivant [q-bio]

Jaime Iranzo, Javier Román, Angel Sánchez. The spatial ultimatum game revisited. Journal of Theoretical Biology, 2011, 278 (1), pp.1. ⟨10.1016/j.jtbi.2011.02.020⟩. ⟨hal-00687018⟩