Age-related variation in physical and social cognition in Barbary macaques (Macaca sylvanus)

到2050年，世界人口的五分之一将超过60岁。由于对社会的巨大影响，几十年来，老龄化的生理基础以及认知能力下降的原因，包括阿尔茨海默病和痴呆症，一直是主要研究方案的核心。最近，老年人的动机倾向的一般变化，以及对社会结构的影响引起了越来越多的关注。在拟议的研究中，我们采取比较的角度来调查社会和认知老化过程的生物学基础。我们将在法国La Foret des Singes的猴围栏中对巴巴利猕猴（Macaca macus）进行行为观察和认知测试。在以前的工作（Almeling et al. 2016，Curr Biol）的基础上，我们揭示了解决问题的能力下降，以及这个物种的社会偏好随着年龄的变化，我们在这里的目标是更详细地研究这些影响的基础。具体来说，我们的目标是进行一系列的认知测试与相同的研究组巴巴利猕猴，以评估抑制控制，认知灵活性和持久性随年龄的变化。此外，我们的目标是测试老年猴子是否表现出积极效应（如人类），即对积极刺激和互动的偏好。为此，我们将向猴子展示亲和和对抗面部表情的图片;此外，我们将记录互动中社会信号的交换。这些行为观察也将使我们能够探索与年龄相关的变化，在社会网络的大小和结构的男性，这还没有在这种情况下进行了研究。我们的研究有可能为更好地理解社会和认知老化提供重要的比较数据，并进一步建立进化生物学和人类寿命研究之间的联系。

By 2050, a fifth of the world's human population will be over 60 years old. Because of the enormous impact on society, the physiological basis of aging, as well as the causes of cognitive decline, including Alzheimer's disease and dementia, have been at the core of major research programmes for several decades. More recently, general changes in the motivational disposition of aging individuals, as well as the consequences for the social fabric of a society have attracted increasing attention. In the proposed study, we take a comparative perspective to investigate the biological basis of social and cognitive aging processes. We will conduct behavioural observations and cognitive tests in Barbary macaques (Macaca sylvanus) at the monkey enclosure La Foret des Singes in France. Building on previous work (Almeling et al. 2016, Curr Biol), where we revealed decreasing performance in problem solving, as well as shifts in social preferences with age in this species, we here aim to investigate the foundations of these effects in more detail. Specifically, we aim to conduct a series of cognitive tests with the same study group of Barbary macaques, to assess variation in inhibitory control, cognitive flexibility, and persistence with age. In addition, we aim to test whether old monkeys show a positivity effect (as humans do), i.e. a preference for positive stimuli and interactions. To this end, we will present the monkeys with pictures of affiliative and agonistic facial expressions; further, we will record the exchange of social signals in interactions. These behavioural observations will also allow us to explore age-related variation in social network size and structure in males, which have not been studied in this context. Our study has the potential to provide important comparative data for a better understanding of social and cognitive aging, and to further forge ties between evolutionary biology and human life-span research.