workshop_2018March

Workshop on evolutionary dynamics, social dynamics, and group behavior

  • Date

    • March 1st (Fri), 2018

  • Time

    • 13:30-19:00

  • Venue

  • Dinner

    • We plan to go to dinner around Tamachi Station after the workshop, presumably from 7pm.

    • For those who wish to join the dinner, please email to Hisashi Ohtsuki (ohtsuki_hisashi [at_mark] soken.ac.jp) by February 14th.

Talks & Schedule (last updated on Jan.10th)

  • 13:30 - 13:40

    • Opening Remark by Hisashi Ohtsuki (SOKENDAI)

  • 13:40 - 14:40

  • Karl Sigmund (University of Vienna)

  • Title

    • Self-domestication and the Social Contract

  • Abstract

    • Many human institutions can be seen as devices to promote cooperation by providing incentives. In particular, such institutions can enforce cooperation by punishing free-riders. In this talk, I will first compare such "pool-punishment" with peer-punishment by game theoretic models and experiments, highlighting the role of voluntary participation. I will then address the weaknesses of both forms of punishment, and in particular the role of corruption. Finally, I will use these approaches to discuss the controversial topic of human self-domestication.

  • Short break

  • 14:50 - 15:20

  • Gaku Oya (SOKENDAI)

  • Title

    • Evolution of aggression-induced cooperation

  • Abstract

    • Cooperative behavior in vertebrates has been mainly explained by reciprocity and kin selection. However, recent literature puts more emphasis on partner-control strategy such as aggression, harassment and punishment. In this study, we made a theoretical model describing social interactions in vertebrates to clarify when and why such partner-control strategy promotes cooperation. We analyzed evolutionary dynamics both in homogeneous and in heterogeneous population in terms of competitive ability and we will discuss the effect of heterogeneity on the evolution of aggression-induced cooperation.

  • 15:20 - 15:50

  • Shun Kurokawa (Kochi University of Technology)

  • Title

    • Persistence extends reciprocity -analysis in the case where information about the opponent player's behavior is sometimes absent-

  • Abstract

    • One key potential explanation for the evolution of cooperation is conditional cooperation. This allows cooperation to evolve for cooperators who switch their behavior on the basis of information about the opponent’s behavior or reputation. However, information about the opponent’s behavior or reputation is sometimes unavailable, and previous studies have assumed that a player cooperates with some default probability when no information about the opponent’s previous behavior or reputation is available. This default probability has been interpreted as the player's “optimism”. Here, we make use of the fact that even if a player cannot observe the opponent's previous behavior or reputation, he may still condition his future behavior based on his own past behavior and in such a case, he can behave persistently. In this talk, we especially consider the case where information about the opponent’s “behavior” is sometimes absent and the iterated prisoner’s dilemma game between the same two individuals is played. Here, we examine the evolution of strategies that can refer to the own behavior in the previous round. Using evolutionarily stable strategy (ESS) analysis and analyzing replicator dynamics, we find that conditioning his future behavior based on his own past behavior is beneficial for the evolution. Persistence facilitates the evolution of cooperation.

  • Short break

  • 16:05 - 16:35

  • Fugo Takasu (Nara Woman's University)

  • Title

    • Spatial evolutionary games as point pattern dynamics - How can classical games be extended to be spatial?

  • Abstract

    • Evolutionary game theory has been successfully applied to explain how animals should behave in a game situation, i.e., payoff to a focal player depends on how its opponent behaves. Classic models include Hawk-Dove game, Prisoners' dilemma, etc. In this talk, I introduce and discuss about an approach how these non-spatial models can be extended as point pattern dynamics where players are distributed over continuous space, not constrained on lattice space that many previous studies have assumed.

  • 16:35 - 17:05

  • Hiroshi Ito (SOKENDAI)

  • Title

    • Evolutionary branching in distorted trait spaces

  • Abstract

    • In multi-dimensional trait spaces, mutation-limited directional evolution is approximately proportional to the multiplication of mutational covariance matrix and the fitness gradient. This relationship holds good even in trait spaces with mutational covariance matrices that are not constant but dependent on the parental phenotypes of the mutants, which are referred to as “distorted trait spaces” here. On the other hand, whether the distortion affects evolutionary branching is not clear. This study develops conditions for evolutionary branching in distorted trait spaces of arbitrary dimensions, and shows that the distortion affects evolutionary branching when the eigenvalues of mutational covariance matrices have significant magnitude difference, i.e., when mutation step-sizes differ significantly among directions.

  • Short break

  • 17:20 - 17:50

  • Mitsuhiro Nakamura (Meiji University)

  • Title

    • Risk-sensitive social learning dynamics of third-party punishment

  • Abstract

    • TBA

  • 17:50 - 18:20

  • Joe Wakano Yuichiro (Meiji University)

  • Title

    • Eco-cultural range expansion of modern humans

  • Abstract

    • TBA

  • 18:20 - 19:00

    • General Discussion by all participants

Acknowledgments

  • This workshop is supported by KAKENHI Grant-in-Aid (16H06324).