Is cumulative culture restricted to modern humans?

现代人能够而且确实积累了文化。这方面的主要证据是我们周围的人工制品，在不同的人类文化中是不同的，这些人工制品不可能由独立于祖先发现的个人重新发明。人类文化传播的机制确保了人类的后代不需要重新发明他们祖先的文化创新，因为早期的成就是代代相传和改进的。这就是累积文化（CC）。作为成年人，我们深受成长环境中的文化的影响;毫无疑问，人类儿童从他人那里学习文化元素。因此，一个重要的问题是，孩子们在什么年龄--以及如何--积累同龄人的文化。PI（Tennie）建议通过向儿童提供制造工具的原材料进行调查，这是一项基本但不寻常的任务（例如收集漂浮物）。实验将使用儿童链，测试他们是否以及如何在“几代”互动中积累文化（儿童A将执行测试任务，而儿童B观看;然后儿童B将在儿童C观看的情况下进行测试，等等）。这种方法将回答这样一个问题，即一般来说，哪种学习机制对于工具使用CC是必要的（模仿，仿真-或两者的混合），因为儿童还不能像成年人那样依赖丰富的CC背景（到目前为止，成年人一直是此类研究的重点）。这使得类人猿成为CC必要机制的理想附加测试案例：如果CC需要模仿，那么类人猿不应该表现出CC。然而，一些大型猿类工具的使用已经被提出作为CC的案例（例如，生产“刷子工具”）。但与人类儿童不同的是，他们可能不是通过模仿获得工具使用技能的。工具使用的存在不是CC的可靠指南（例如啄木鸟雀）。类人猿在观察到其他人的行为结果后，可能会重新发明有效使用工具所需的技术-这将是模仿学习。PI以前将这种学习策略称为“潜在解决方案区”，其中潜在解决方案是猿类成功地为自己发明的技术。近年来，PI已经开发了几种研究范式，以验证大猿不会从彼此身上学到很多东西的预测，而“文化”学习的案例只证明了自发的创新。特别重要的是一项研究，他为天真的猿（大猩猩）提供了被认为需要在野外进行文化传播的行为（微妙的荨麻喂养技能）的原材料。这些被测试的圈养大猩猩自发地发明了这些行为，尽管它们从未见过。利用同样的方法，PI计划继续向天真的猿类提供野生“文化”行为所涉及的原材料的战略。如果天真的受试者表现出这种“狂野”行为，这不可能是CC的结果，而只是一种潜在的解决方案。如果野生类人猿的所有假定的文化行为都被证明是潜在的解决方案，那么人类文化可能是人类独特的模仿学习倾向的结果。因此，仅仅模仿（如类人猿所使用的）可能不足以促进文化交流。因此，拟议的项目将确定大自然是否将类人猿文化（而不是人类文化）“拴在皮带上”。它对我们看待早期原始人石器的方式有重要的影响，考古记录显示，其中一些石器保持了数百万年的基本形式。对这种缺乏变化的最好解释可能是这些工具--作为现代类人猿的工具--是潜在的解决方案。

Modern humans can and do accumulate culture. Primary evidence for this are the artefacts around us, different across different human cultures, which could not be reinvented by individuals working independently of the discoveries of their forebears. The mechanisms of human cultural transmission ensure that successive generations of humans need not reinvent the cultural innovations of their forebears, as earlier achievements are passed down and improved across generations. This is cumulative culture (CC).As adults, we are heavily influenced by the culture in which we grew up; and there is no question that human children learn elements of culture from others. Thus, an important question is at what age - and how - children accumulate the culture of their peers. The PI (Tennie) proposes to investigate this by providing children with raw materials for tool manufacture, in a basic, but unusual, task (e.g. collecting floating objects). Using chains of children, the experiments will test if and how they accumulate culture across "generations" of interaction (child A will perform the test task while child B watches; then child B will be tested while child C watches, and so on). Such a method will answer the question of which learning mechanisms are necessary for tool use CC in general (imitation, emulation - or a mixture of both) since children cannot yet rely on the same rich CC background as adults (who so far have been the focus of such studies).Current evidence suggests that great apes are poor at one particular learning mechanism: imitation. This renders great apes an ideal additional test case for the necessary mechanisms for CC: if imitation is required for CC, then great apes should not show CC. Yet, some great ape tool use has been proposed as cases of CC (e.g., producing "brush tools"). But it may be that unlike human children they do not acquire their tool using skills through imitation. The existence of tool use is not a reliable guide to CC (e.g. woodpecker finches). Great apes may basically re-invent the techniques required for efficient tool use for themselves after observing the outcomes of others actions - this would be emulation learning. The PI has previously termed this learning strategy the "zone of latent solutions", where latent solutions are the techniques that apes succeed in inventing for themselves.In recent years the PI has developed several research paradigms that test the prediction that great apes do not learn so much from one another, and that cases of 'cultural' learning testifies instead only to spontaneous innovations. Of special importance is a study in which he provided naïve apes (gorillas) with the raw materials for behaviours thought to require cultural transmission in the wild (delicate nettle feeding skills). The tested captive gorillas spontaneously invented these behaviours despite never having seen them. Using the same methodology, the PI plans to continue the strategy of providing naïve apes with the raw materials involved in wild "cultural" behaviour. If naïve subjects show this 'wild' behaviour, it cannot be the consequence of CC but only a latent solution. If all putative cultural behaviours in wild great apes turn out to be latent solutions, then human culture may be the consequence of a uniquely human tendency to engage in imitative learning. Emulation alone (as used by great apes) may thus not be sufficient for CC.The proposed project will therefore determine whether nature put great ape - but not human - cultures "on a leash". It has important implications for the way we view early hominid stone tools, some of which the archaeological record shows kept their basic forms for millions of years. The best explanation for this lack of change may be that these tools - as modern great ape tools - were latent solutions.