Behavioural Flexibility, Fertility and Social Network Influences in Human and Non-Human Primates

我的目的是了解进化过程如何影响人类和非人类灵长类动物的行为。更具体地说，我感兴趣的是探索我们与其他灵长类动物共有的那些方面，以及那些使我们不同的方面。一个共同的特征被认为是我们高度的行为灵活性，即应对生态和社会环境变化的能力。然而，与此同时，人类和其他灵长类动物已被证明具有稳定的个性；也就是说，我们的行为在不同的时间和环境中往往是一致的。在不同的环境中表现出同样的行为是与灵活性背道而驰的，这引发了为什么应该存在稳定的人格特征的问题。在这里，我提议调查南非长尾猴的个性和可塑性之间的联系。有人认为，个体之间生长速度的持续差异导致了稳定的个性特征（例如，生长速度快的动物可能需要更有攻击性、更活跃、承担更多风险，以确保它们通过觅食满足能量需求），而且这种差异可能会在发育过程中得到加强。纵向研究，结合观察和实验数据，从婴儿期到成年期，可以帮助回答这个问题。也有人认为，个性和可塑性是互补的：动物可能在行为上表现出平均差异，它们对环境变化的反应强度也可能有所不同。通过对长尾猴的实验和观察数据，我将测试性格是否能预测个体内部和个体之间的可塑性，以及这在不同的生命阶段和性别之间是否存在差异。这些数据将提供有关vervet可塑性范围和限制的宝贵信息，以及它们应对快速气候变化的可能能力。我的建议的第二部分是关于人类行为的，重点是我们与其他灵长类动物的区别。在这里，重点是现代工业经济中的文化变迁如何影响生育决策，导致家庭规模比进化论预测的要小得多。一种说法是，经济发展导致我们的社会网络发生变化（联系更弱，亲缘关系更少），这反过来又影响了生育的决定。在这里，我的学员、合作者和我将比较生育率低于更替水平（每名妇女生育1.61个孩子）的加拿大与生育率仍然很高（每名妇女生育5.10个孩子）的欠发达国家萨摩亚的社会网络。了解生育率变化的原因，以及影响人们生育决定的因素，将有助于更准确地预测人口，并有可能解释为什么在工业国家，人们有时无法达到家庭规模目标。

My aim is to understand how evolutionary processes influence the behaviour of human and non-human primates. More specifically, I am interested in exploring those aspects that we share with other primate species, and those that make us different. One shared feature is argued to be our high level of behavioural flexibilitythe ability to cope with changes in the ecological and social environment. At the same time, however, humans and other primates have been shown to possess stable personalities; that is, our behaviour is often very consistent across time and circumstance. Displaying the same behaviour over different contexts is the very opposite of flexibility, and raises questions of why stable personality traits should exist. *** Here, I propose to investigate the link between personality and plasticity among South African vervet monkeys. It has been argued that consistent differences in growth rate between individuals leads to stable personality traits (e.g., animals that are growing fast may need to be more aggressive, more active and take more risks to ensure they meet their energy demands via foraging), and that such differences may be reinforced over the course of development. Longitudinal studies, combining observational and experimental data, from infancy to adulthood, can help answer this question. It has also been suggested that personality and plasticity are complementary: animals may show average differences in their behaviour, and they may also vary in the strength of their response to environmental change. Using experimental and observational data on vervet monkeys, I will test whether personality predicts plasticity within and between individuals, and if this varies across different life stages and between the sexes. These data will provide valuable information on the scope and limits of vervet plasticity, and their likely ability to cope with rapid climate change. *** The second part of my proposal deals with human behaviour, and focuses on our differences from other primates. Here, the emphasis is on how cultural shifts in modern, industrial economies influence reproductive decisions, leading to much smaller family sizes than evolutionary theory predicts. One suggestion is that economic development leads to changes in our social networks (weaker links, with fewer kin), which in turn affects the decision to reproduce. Here, my trainees, collaborators and I will compare social networks in Canada, where fertility is below replacement levels (1.61 children per woman), with a less developed nation, Samoa, where fertility remains high (5.10 children per woman). Understanding why fertility varies, and what influences people's reproductive decisions will help contribute to more accurate population forecasts, and potentially explain why people sometimes fail to reach their family size goals in industrial nations.