By 2050, a fifth of the world’s human population will be over 60 years old. Studies of the physiological basis of aging, as well as the causes of cognitive decline, including Alzheimer’s disease and dementia, are therefore attracting substantial attention. We aim to investigate cognitive aging processes in nonhuman primates, using cognitive tests in Barbary macaques (Macaca sylvanus) at the monkey enclosure “La Forêt de Singes” in France. Specifically, we aim to conduct a series of cognitive tests with the same study group of individuals, to assess variation in inhibitory control, cognitive flexibility, and persistence with age. Our study has the potential to provide important comparative data for a better understanding of cognitive aging, and to further forge ties between evolutionary biology and human life-span research.