<p>This dissertation is a collection of three papers, each one being a chapter. The running subject of interest in all the papers is the strategic behavior of individuals in different environments. In the first chapter, I experimentally investigate collusive behavior under simultaneous interaction in multiple strategic settings, a phenomenon which I call multiple contacts. I investigate how multiple contacts impact collusive behavior when the players are symmetric or asymmetric. The second chapter is a joint work with Dr. Brian Roberson. In this chapter, we examine the role of cognitive diversity in teams on performance in a large innovation contest setting. We use a theoretical model to derive conditions under which increasing diversity can improve the performance in the large contest. Finally, in the third chapter, a joint work with Dr. Yaroslav Rosokha and Dr. Masha Shunko, we experimentally study players' behavior when they interact in an infinitely repeated environment, where the state of the world in each period is stochastic and dependent on a transition rule. Our main questions are how the transition rule impacts behavior and whether asymmetry in players impacts this.</p> <p><br></p> <p>In the first chapter, I study the phenomenon of multiple contacts using a laboratory experiment with multiple symmetric or asymmetric prisoners' dilemma games. When agents interact in multiple settings, even if defection or deviation from collusion in one setting can not be credibly punished in the same setting, it may be punishable in other settings. This can increase the incentive to collude. I observe a statistically significant increase in probability of punishment in one game after defection in another game under multiple contacts, but only when the games are asymmetric in payoffs. While punishment of defection increases in some situations, I do not find any significant increase in collusion due to multiple contacts in either symmetric or asymmetric environment. In addition to this result, to find further support for the theory which suggests that agents should use different strategies under multiple contacts, I estimate the underlying strategies that subjects use in my experiment. To this end, I modify popular strategies (e.g., Grim Trigger, Tit-for-Tat, etc.) to condition on the history observed in multiple strategic settings. I find that only for games with asymmetric payoffs subjects use these modified strategies in the presence of multiple contacts.</p> <p><br></p> <p>The second chapter is a theoretical work. In our model of large team innovation contest, teams develop an innovation using the skills or perspectives (tools) belonging to individual team members and the costly effort they provide.</p> <p>Prizes are awarded based on the values of the teams' innovations. Within a team, the team members posses different skills or perspectives (tools) which may be applied to innovation problems. For a given innovation problem and a given level of team effort, different combinations of tools within a team may generate different values for the team innovation. In this context, we examine the issues of individual team performance as a function of a team's own composition and the overall performance of the contest as a function of the compositions of the teams. We find that the question of whether increasing diversity leads to an increase in expected performance, for both an individual team and the overall contest, depends on the efficiency with which teams are able to effectively apply diverse sets of tools to innovation problems. Thus, our paper provides a channel -- other than a direct cost of diversity -- through which diversity can be beneficial or detrimental depending on how efficient teams are at utilizing diverse sets of team member tools.</p> <p><br></p> <p>The final chapter is another experimental study. We study an enviroment where individuals interact with each other in a prisoners' dilemma game repeatedly over time. However, the payoffs of the prisoners' dilemma game is decided stochastically using a transition rule. We vary the transition rule from alternation to random and study the change in subject behavior when the interaction is either symmetric or asymmetric. Our results show that in asymmetric environment, alternation can improve cooperation rates.</p> <p>With random transition rule, symmetric environment is more conducive to cooperation. We find that asymmetric environment with random transition rules performs the worst in terms of cooperation rates.</p>

L’altruisme réciproque, le mécanisme le plus vraisemblable expliquant l’existence de la coopération entre individus non-apparentés, peut être modélisé par le Dilemme du Prisonnier. Ce jeu prédit que la coopération devrait évoluer lorsque les joueurs prévoient d’interagir ensemble à maintes reprises et adoptent des stratégies conditionnelles telles que «Tit-For-Tat» ou Pavlov. Bien que la coopération soit à la source de toutes sociétés humaines, celle-ci est rarement observée chez les animaux. Une explication plausible serait que ces derniers sont plus impulsifs que les humains. Plusieurs études ayant évalué les effets de l’impulsivité sur la coopération ont en effet trouvé un impact négatif du phénomène de « discounting » sur la réciprocité. Néanmoins, l’impulsivité n’est pas un concept unitaire et le rôle de l’impulsivité motrice, une autre facette de l’impulsivité, reste inexploré, alors qu’elle pourrait également restreindre la coopération en altérant la capacité des individus à ajuster de manière flexible leur comportement face aux décisions prises par leur partenaire. En effet, l’impulsivité motrice se définit comme étant l’incapacité à inhiber un comportement qui n’est plus approprié suite à un changement de situation et est donc contreproductif (Broos et al., 2012; MacLean et al., 2014). Pour résoudre cette hypothèse, nous avons mené une expérience avec des diamants mandarins (Taenyopigia guttata) que nous avons appariés en fonction de leur niveau d’impulsivité motrice, puis nous les avons fait jouer dans un Dilemme du Prisonnier Alterné. Tel qu’attendu, nous avons trouvé que la coopération mutuelle survenait plus fréquemment entre les partenaires autocontrôlés que les paires d’individus impulsifs, ce qui serait dû à une différence entre les stratégies employées par les deux types d’individus. Plus précisément, les individus autocontrôlés utilisaient une stratégie « Generous TFT », tel que prédit par la théorie, alors que les oiseaux impulsifs choisissaient de coopérer avec une probabilité fixe, laquelle était indépendante de la décision précédemment prise par le partenaire. Si l’incapacité des individus impulsifs à utiliser des stratégies réactionnelles est due à une capacité de la mémoire de travail réduite, nos résultats pourraient alors contribuer à expliquer les différences interspécifiques qui existent au niveau des comportements coopératifs. / Reciprocal altruism, the most probable mechanism for cooperation among unrelated individuals, can be modelled as a Prisoner’s Dilemma. This game predicts that cooperation should evolve whenever the players, who expect to interact repeatedly, adopt conditional strategies. Yet, experimental data suggest that reciprocity would be rare in animal societies, maybe because animals, compared to humans, are very impulsive. Several studies examining the effect of impulsiveness on cooperation have indeed found a negative impact of temporal discounting. On the other hand, the role of impulsive action, another facet of impulsiveness, remains unexplored, though it could also impede cooperation by affecting the capacity of individuals to flexibly adjust their behaviour to their partner’s decision. To address this hypothesis, we conducted an experiment with zebra finches (Taenyopigia guttata) that were paired assortatively with respect to their level of impulsive action and then played an Alternating Prisoner’s Dilemma. As anticipated, we found that mutual cooperation occurred more frequently between self-controlled partners than between impulsive ones, a difference that was caused by differences in the strategy used by both types of individuals. Specifically, self-controlled individuals used a Generous TFT strategy, as predicted by theory, whereas impulsive birds chose to cooperate with a fixed probability, which was independent of their partner’s previous decision. If the inability of impulsive individuals to use reactive strategies are due to their reduced working memory capacity, our findings might contribute to explaining interspecific differences in cooperative behaviour.

為瞭解兒童在認知發展行為的表現，本研究招募國小一年級學童56名，五年級學童32名參與實驗進行。應用囚犯困境賽局與最後通牒賽局之架構設計兩個遊戲，來檢測兒童在合作與分享行為之表現。分析受試者之背叛比率、提供數量、拒絕比率等實驗資料，來檢測年齡、性別以及長幼關係是否會造成顯著影響。 實驗結果發現： （1）年齡較大兒童較傾向較合作且拒絕比率較低，這個結果和認知發展理論的結論一致。 （2）受試者資料在性別效果的假設檢定結果都不顯著。 （3）年齡較小兒童的平均提供數量都大於一半，這個結果和最後通牒賽局的理論預測相反。（4）對手為不同年齡時的背叛比率和拒絕比率都比對手為同年齡時低，這個結果支持國小開設混齡教育課程。 / This paper studies children’s behavior in an ultimatum game and a prisoner’s dilemma game with 56 children of age 7 and 32 children of age 11. With the experimental data of defect ratio, offer quantity and rejection ratio, we tested the age, sex and seniority effects under these two games. The experimental findings are as follows. （1）The older children are more cooperative and have lower rejection ratio than younger ones. These results are consistent with the developmental psychology theories. （2） We observe no significant sex effect in the three tests. （3） For younger children, the average offer quantity is higher than fifty percent, this is different from theoretical prediction and literature results.（4）We found that for pairs consisting of subjects of different ages, The defect ratio and rejection ratio are lower than pairs of the same age subjects. This evidence may provide support for mixed-age education program for some courses in elementary school.

L’émergence de la complexité, et de la vie en particulier, demeure l’une des énigmes les plus complexes pour la science moderne. Des travaux récents ont souligné la pertinence d’un apport de la physique statistique et de la théorie des phénomènes critiques — et en particulier de la théorie des phénomènes à criticalité auto-régulée — relativement à ces champs d’intérêt, tout autant que du rôle des phénomènes de coopération biochimique dans les premiers instants du vivant. La description des mécanismes par lesquels la vie a pu apparaître est par ailleurs d’un intérêt pratique pour l’astrophysique, puisque notre compréhension de ceux-ci module la manière dont l’analyse de biosignatures s’effectue dans le cadre de la recherche de la vie ailleurs dans l’Univers. L’analyse proposée ici porte sur un modèle en théorie des jeux permettant d’étudier les phénomènes de coopération implémenté dans un contexte spatial servant à émuler la dynamique d’un système ayant pu voir apparaître la vie. Une analyse de l’espace des paramètres du modèle révèle que celui-ci affiche des phénomènes de transition de phase et d’auto-organisation de structures spatiales, ces éléments se révélant des adjuvants à l’émergence de la coopération entre joueurs a priori égoïstes, dans un contexte qui à prime abord n’est pas d’emblée favorable à l’apparition de comportements coopératifs. Les résultats obtenus ici semblent supporter que la coopération biochimique puisse apparaître via un phénomène de transition de phase et que le modèle sous-jacent de dilemme du prisonnier itéré sur réseau présenté ici agit comme un système à criticalité autorégulée. / The emergence of complexity, and of life more specifically, is still one of the most intractable conundrums for modern science. Recent work emphasized the relevance of statistical physics and critical phenomena theory’s contribution to those questions — especially of self-organized criticality theory — just as much as the role of biochemical cooperation in life’s first moments. Moreover, the description of the mechanisms by which life could have appeared is of particular interest for astrophysics, because our comprehension of those mechanisms influences how biosignatures are analyzed in the context of the search for life elsewhere in the Universe. The analysis presented here concerns a model in game theory that allows to study cooperation phenomena — implemented in spatial context as to emulate the dynamics of a system in which life could have appeared. An analysis of the model’s parameter space reveals that it displays phase transition and self-organization of spatial structures phenomenon, those elements being adjuvants to the emergence of cooperation between a priori egoist players, in a context that is initially not favorable to the emergence of cooperative behavior. The results obtained here thus seem to support the idea that both biochemical cooperation can emerge through phase transition phenomena, and that the underlying lattice iterated prisoner’s dilemma model used here behaves like a self-organized critical system.

許多企業的經理人一直在尋求有效的政策以促進員工彼此分享知識。在組織中實施激勵知識分享的政策，因為存在著許多的個人與組織的因素，兩者相互作用會影響組織的成員知識分享的行為，政策的效果很難掌握。在實務上，不同的組織激勵的政策或手段的效果，欲通過田野調查或實驗設計來評估政策所帶來效果及對組織成員行為的影響不容易實現。因此，本研究嘗試運用一項新穎的研究策略-代理人基塑模(agent-based modeling)，經由建構一個人造的世界來模擬組織成員知識分享的行為。在這個人造的社會中，研究者考慮了知識分享的報酬、組織成員的行為策略、行為策略的學習與適應機制、不同組織的群體能力水準、互動的網路、知識的選擇模式與不同的組織激勵政策設計等變數，藉以設計相關的實驗。模擬的結果產生了的幾項有趣的發現： (1) 當分享知識的報酬愈高時，代理人知識分享行為會愈多，無論是在那一種的互動網路、群體能力或分享知識的選擇模式的情況之下。(2) 代理人的互動網路是一項重要影響因素，互動網路扮演著知識流通與行為策略學習的管道，它同時會影響個體知識分享的報酬與行為策略的學習。它可能促成不分享的策略的擴散，可能會提升組織激勵的效果，也可能會增強激勵所帶來的副作用。(3) 個體的知識分享與吸收的能力如果存有差異，則能力較好的代理人將會局部地吸引能力較差的互動對象採用他的策略，即使他所用的不是可以獲致最佳報酬策略。(4) 為促進組織成員分享知識，定期審視固定獎勵的作法可以導致比較好的效果，不但可以提升分享知識的行為，也使代理人比較願意採用傾向分享知識的策略，促成組織信任的氣氛。但是，在某些情況下，可能造成反效果。(5) 最後，根據實驗的結果與研究的發現，研究者建構了一個知識分享之組織行為模型，以做為後續實證研究之參考架構。 / Mangers always look for effective policies to prompt knowledge sharing between members in an organization. It is difficult to evaluate the effect of incentive policies for stimulating knowledge sharing because there are many individual and organizational factors. In practice, it is not easy to assess the effects of different incentive policies or methods by the methods of experiment or field investigation. Therefore, a novel research strategy is applied in this study, which is called agent-based modeling. An artificial world was constructed to simulate the knowledge sharing interactions between members in an organization. This study considers some parameters including the payoff of knowledge sharing, the strategies of members, the learning and adaption mechanism of strategies, collective capabilities, interactive network, the selection methods of sharing knowledge and incentive policies to design experiments in the agent-based model. The results of simulations produced some interesting findings: (1) the higher the payoff of sharing knowledge, the more the actions of sharing knowledge is in spite of any kind of interactive networks, collective capabilities, and the selection methods of sharing knowledge. (2) Interactive Network of agents is an important factor, which plays a role of channel of knowledge transition and strategy learning. It simultaneously affects the payoff of knowledge sharing and learning of strategy. It maybe results in the diffusion of strategy of not sharing knowledge, or enhances the effect and side effect brought by incentive policies. (3) Because of difference between agents’ capabilities, agents with better capabilities will locally attract the ones with worse capabilities to learn their strategies, which even are not the best. (4) To enable sharing knowledge between members in an organization, periodic reward will get better results. It does not only increase the action of sharing knowledge, but also make agents to adop the strategies trending toward sharing knowledge. Periodic reward is helpful to form a trustful organization climate. However, in some circumstances, it may get minus effects. (5) Finally, according to experimental results and research findings, an organization behavior model of knowledge sharing has been constructed for the empirical studies in the future.

Le fichiers qui accompagnent mon document ont été réalisés avec le logiciel Mathematica / Dans cette thèse, nous étudions la théorie des jeux évolutionnaires dans quelques exemples de populations structurées. En particulier, nous analysons l’évolution de la coopération en déterminant des conditions qui la favorisent dans le cas des interactions par paire. On s’intéresse à l’évolution de la coopération dans un espace phénotypique de dimension quelconque. Puis on étudie la coopération dans une population finie, subdivisée en groupes de même quelconques avec une hiérarchie entre les groupes. Finalement, on présente l’effet de l’aspiration sur le processus évolutif dans une population finie répartie sur un cercle où il y a des positions à occuper. / In this thesis, we study some examples of structured populations. In particular, we analyze the evolution of cooperation in the sense of determining conditions that favor it. We study the evolution of cooperation in a phenotype space of any size. We study also the evolution of cooperation in a finite population subdivided into hierarchical groups of any size. Finally, we study the effect of aspiration on the evolutionary process in a finite population distributed on a circle with only a local interaction by pairwise.