Ashlock D, Smucker M D, Stanley E A, Tesfatsion L
Department of Mathematics, Iowa State University, Ames 50011-1070, USA.
Biosystems. 1996;37(1-2):99-125. doi: 10.1016/0303-2647(95)01548-5.
Partner selection is an important process in many social interactions, permitting individuals to decrease the risks associated with cooperation. In large populations, defectors may escape punishment by roving from partner to partner, but defectors in smaller populations risk social isolation. We investigate these possibilities for an evolutionary Prisoner's Dilemma in which agents use expected payoffs to choose and refuse partners. In comparison to random or round-robin partner matching, we find that the average payoffs attained with preferential partner selection tend to be more narrowly confined to a few isolated payoff regions. Most ecologies evolve to essentially full cooperative behavior, but when agents are intolerant of defections, or when the costs of refusal and social isolation are small, we also see the emergence of wallflower ecologies in which all agents are socially isolated. Between these two extremes, we see the emergence of ecologies whose agents tend to engage in a small number of defections followed by cooperation thereafter. The latter ecologies exhibit a plethora of interesting social interaction patterns.
伙伴选择是许多社会互动中的一个重要过程，它使个体能够降低与合作相关的风险。在大群体中，背叛者可能通过不断更换伙伴来逃避惩罚，但在小群体中的背叛者则面临社会孤立的风险。我们研究了在进化囚徒困境中的这些可能性，在这种困境中，参与者利用预期收益来选择和拒绝伙伴。与随机或循环伙伴匹配相比，我们发现通过优先选择伙伴获得的平均收益往往更狭窄地局限于少数几个孤立的收益区域。大多数生态系统会进化到基本完全合作的行为，但当参与者不能容忍背叛行为时，或者当拒绝和社会孤立的成本很小时，我们也会看到壁花生态系统的出现，在这种生态系统中所有参与者都处于社会孤立状态。在这两个极端之间，我们看到了一些生态系统的出现，其参与者倾向于先进行少量的背叛行为，然后再进行合作。后一种生态系统展现出了大量有趣的社会互动模式。
