Anthropological Institute and Museum, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
J Hum Evol. 2012 Jul;63(1):180-90. doi: 10.1016/j.jhevol.2012.04.008. Epub 2012 Jun 2.
Culturally supported accumulation (or ratcheting) of technological complexity is widely seen as characterizing hominin technology relative to that of the extant great apes, and thus as representing a threshold in cultural evolution. To explain this divide, we modeled the process of cultural accumulation of technology, which we defined as adding new actions to existing ones to create new functional combinations, based on a model for great ape tool use. The model shows that intraspecific and interspecific variation in the presence of simple and cumulative technology among extant orangutans and chimpanzees is largely due to variation in sociability, and hence opportunities for social learning. The model also suggests that the adoption of extensive allomaternal care (cooperative breeding) in early Pleistocene Homo, which led to an increase in sociability and to teaching, and hence increased efficiency of social learning, was enough to facilitate technological ratcheting. Hence, socioecological changes, rather than advances in cognitive abilities, can account for the cumulative cultural changes seen until the origin of the Acheulean. The consequent increase in the reliance on technology could have served as the pacemaker for increased cognitive abilities. Our results also suggest that a more important watershed in cultural evolution was the rise of donated culture (technology or concepts), in which technology or concepts was transferred to naïve individuals, allowing them to skip many learning steps, and specialization arose, which allowed individuals to learn only a subset of the population's skills.
文化支持的技术复杂性积累（或棘轮效应）被广泛认为是人类技术相对于现存大猿类技术的特征，因此代表了文化进化的一个门槛。为了解释这种差异，我们基于大猿类工具使用模型，对技术文化积累的过程进行了建模，我们将技术文化积累定义为在现有动作基础上增加新动作以创造新的功能组合。该模型表明，现存猩猩和大猩猩中简单技术和累积技术在种内和种间的存在差异主要是由于社交性的差异，以及由此产生的社会学习机会的差异。该模型还表明，在早期更新世人类中采用广泛的异体养育（合作繁殖），这导致了社交性的增加和教学的出现，从而提高了社会学习的效率，这足以促进技术的棘轮效应。因此，社会生态变化而不是认知能力的提高可以解释直到阿舍利文化起源为止所看到的累积文化变化。对技术的依赖增加可能是认知能力提高的起搏器。我们的研究结果还表明，文化进化中一个更重要的分水岭是捐赠文化（技术或概念）的兴起，在这种文化中，技术或概念被转移到天真的个体身上，使他们能够跳过许多学习步骤，从而出现专业化，使个体只学习群体技能的一个子集。
