Department of Developmental and Comparative Psychology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.
PLoS One. 2011;6(10):e23223. doi: 10.1371/journal.pone.0023223. Epub 2011 Oct 7.
Human cooperation is a key driving force behind the evolutionary success of our hominin lineage. At the proximate level, biologists and social scientists have identified other-regarding preferences--such as fairness based on egalitarian motives, and altruism--as likely candidates for fostering large-scale cooperation. A critical question concerns the ontogenetic origins of these constituents of cooperative behavior, as well as whether they emerge independently or in an interrelated fashion. The answer to this question will shed light on the interdisciplinary debate regarding the significance of such preferences for explaining how humans become such cooperative beings. We investigated 15-month-old infants' sensitivity to fairness, and their altruistic behavior, assessed via infants' reactions to a third-party resource distribution task, and via a sharing task. Our results challenge current models of the development of fairness and altruism in two ways. First, in contrast to past work suggesting that fairness and altruism may not emerge until early to mid-childhood, 15-month-old infants are sensitive to fairness and can engage in altruistic sharing. Second, infants' degree of sensitivity to fairness as a third-party observer was related to whether they shared toys altruistically or selfishly, indicating that moral evaluations and prosocial behavior are heavily interconnected from early in development. Our results present the first evidence that the roots of a basic sense of fairness and altruism can be found in infancy, and that these other-regarding preferences develop in a parallel and interwoven fashion. These findings support arguments for an evolutionary basis--most likely in dialectical manner including both biological and cultural mechanisms--of human egalitarianism given the rapidly developing nature of other-regarding preferences and their role in the evolution of human-specific forms of cooperation. Future work of this kind will help determine to what extent uniquely human sociality and morality depend on other-regarding preferences emerging early in life.
人类合作是我们人类谱系进化成功的关键驱动力。在接近的水平上，生物学家和社会科学家已经确定了其他关注的偏好，如基于平等动机的公平和利他主义，作为促进大规模合作的可能候选者。一个关键问题涉及到这些合作行为成分的个体发生起源，以及它们是独立出现还是以相互关联的方式出现。这个问题的答案将阐明关于这些偏好对于解释人类如何成为如此合作的生物的意义的跨学科争论。我们调查了 15 个月大的婴儿对公平的敏感性，以及他们的利他行为，通过婴儿对第三方资源分配任务的反应以及通过分享任务来评估。我们的结果在两个方面挑战了公平和利他主义发展的当前模型。首先，与过去的工作表明公平和利他主义可能直到幼儿期中期才会出现的观点相反，15 个月大的婴儿对公平敏感，可以进行利他主义分享。其次，婴儿作为第三方观察者对公平的敏感性程度与他们是否利他或自私地分享玩具有关，表明道德评价和亲社会行为从早期就紧密相连。我们的结果首次表明，基本公平感和利他主义的根源可以在婴儿期找到，并且这些其他关注的偏好以平行和交织的方式发展。这些发现支持了人类平等主义的进化基础的论点，最有可能以辩证的方式包括生物和文化机制，考虑到其他关注的偏好的快速发展性质及其在人类特定形式的合作进化中的作用。这种未来的工作将有助于确定独特的人类社会性和道德在多大程度上取决于生命早期出现的其他关注的偏好。
