Abstract We introduce a new spatial prisoner’s dilemma (SPD) model in which the so-called network reciprocity is enhanced more than in the conventional model. In addition to the usual binary strategies—perfect cooperator and perfect defector—we introduce “fence-sitters”, who either cooperate or defect with equal probability, as a third strategy. In regions with larger Stag-Hunt-type dilemmas but smaller Chicken-type dilemmas, the existence of the fence-sitters works as a buffer, hampering the exploitation of cooperators by neighboring defectors and significantly enhancing the cooperative phase. Conversely, in regions with larger Chicken-type dilemmas but smaller Stag-Hunt-type dilemmas, the existence of the fence-sitters expands the critical dilemma strength for the survival of cooperation, but it reduces the cooperating fraction more than in the conventional model. What we have found may justify the conclusion that the existence of people with neutral opinions—often regarded betwixt and between—absorbs the severe competition between two extreme groups, bringing a more accommodationist situation to our society, backed with greater cooperation.

中文翻译：

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守栅人的存在缓解了空间囚徒困境，增强了网络互惠

摘要 我们引入了一种新的空间囚徒困境（SPD）模型，其中所谓的网络互惠性比传统模型中的增强更多。除了通常的二元策略——完美的合作者和完美的叛逃者——我们引入了“守围者”，他们以相等的概率合作或叛逃，作为第三种策略。在雄鹿型困境较大但鸡型困境较小的地区，围栏保姆的存在起到了缓冲作用，阻碍了相邻叛逃者对合作者的利用，并显着增强了合作阶段。反之，在鸡类困境较大而雄鹿类困境较小的地区，围栏的存在扩大了合作生存的临界困境强度，但它比传统模型减少了更多的合作部分。我们的发现可能会证明这样的结论是正确的，即持有中立观点的人的存在——通常被认为是介于两者之间——吸收了两个极端群体之间的激烈竞争，给我们的社会带来了更加妥协的局面，并得到了更多合作的支持。