How group composition affects cooperation in fixed networks: can psychopathic traits influence group dynamics?

Static networks have been shown to foster cooperation for specific cost-benefit ratios and numbers of connections across a series of interactions. At the same time, psychopathic traits have been discovered to predict defective behaviours in game theory scenarios. This experiment combines these two aspects to investigate how group cooperation can emerge when changing group compositions based on psychopathic traits. We implemented a modified version of the Prisoner’s Dilemma game which has been demonstrated theoretically and empirically to sustain a constant level of cooperation over rounds. A sample of 190 undergraduate students played in small groups where the percentage of psychopathic traits in each group was manipulated. Groups entirely composed of low psychopathic individuals were compared to communities with 50% high and 50% low psychopathic players, to observe the behavioural differences at the group level. Results showed a significant divergence of the mean cooperation of the two conditions, regardless of the small range of participants’ psychopathy scores. Groups with a large density of high psychopathic subjects cooperated significantly less than groups entirely composed of low psychopathic players, confirming our hypothesis that psychopathic traits affect not only individuals’ decisions but also the group behaviour. This experiment highlights how differences in group composition with respect to psychopathic traits can have a significant impact on group dynamics, and it emphasizes the importance of individual characteristics when investigating group behaviours.

已有研究表明，静态网络（Static networks）在一系列交互场景中，可在特定成本收益比与连接数量的条件下促进合作行为。与此同时，研究发现精神病态特质（psychopathic traits）可预测博弈论场景中的偏差行为。本实验将上述两个研究方向相结合，旨在探究基于精神病态特质调整群体构成时，群体合作行为将如何涌现。我们搭建了一款经过修改的囚徒困境博弈（Prisoner’s Dilemma game），该博弈的理论与实证研究均已证明，其可在多轮博弈中维持稳定的合作水平。本实验招募190名本科生作为被试，将其划分为若干小型群体，并操控每组内高精神病态特质被试的占比。实验设置两类对照群体：一类为全部由低精神病态特质被试组成的群体，另一类为高、低精神病态特质被试各占50%的混合群体，以此观察群体层面的行为差异。结果显示，无论被试的精神病态特质得分处于较小的区间范围内，两类群体的平均合作水平均存在显著差异。高精神病态特质被试占比更高的群体，其合作水平显著低于全低精神病态特质被试组成的群体，这一结果验证了我们的假设：精神病态特质不仅会影响个体决策，还会作用于群体行为。本实验揭示了基于精神病态特质的群体构成差异，会对群体动力学（group dynamics）产生显著影响，并强调了在研究群体行为时，个体特征的重要性。