Despite the controlled testing conditions that are typical of captive environments, many evaluations of animal cognition fail to ensure that all tested individuals participate. This is even more evident under wild conditions, as animals are not restricted in their movement or social interactions and have other activities available. In this study, we aimed to understand variation in cognitive task participation in wild chacma baboons, Papio ursinus. We quantified individual differences in the latency and likelihood to approach and explore two types of stimuli for two cognitive tests: a set of coloured paper bags (in an associative learning test) and a blue cardboard square (in a second-order conditioning test). We evaluated whether participation in each task was predicted by individuals’ phenotypic traits/states, as well as by two additional aspects of their behaviour: (1) the availability of competing activities at the time of testing and (2) their propensity to exploit social information. We found consistent results for both types of stimuli regarding the effect of age: juveniles were more likely to contact the stimuli and explore them for longer. Similarly, for both tasks, individuals involved in an activity at the time of testing were less likely to contact the stimuli and had a lower exploration time. Finally, juveniles and females with a high propensity to use social information (i.e. scrounge) were more likely, and had shorter latencies, to contact the paper bags. Our findings not only highlight the potential bias cognitive studies conducted in the wild can have, but also some of the individual attributes and external factors that determine task participation.

尽管圈养环境具有典型的受控测试条件，但对动物认知的许多评估仍无法确保所有测试人员都能参与。这在野外条件下更加明显，因为动物的活动或社交活动不受限制，并且可以进行其他活动。在这项研究中，我们旨在了解野生Chacma狒狒，Papio ursinus中认知任务参与的差异。我们对潜伏期和接近可能性的个体差异进行了量化，并探讨了两种认知测试的两种类型的刺激：一组彩色纸袋（在关联学习测试中）和蓝色硬纸板（在二次条件测试中）。我们评估了是否通过个人的表型特征/状态以及其行为的两个其他方面来预测每个任务的参与：（1）测试时竞争活动的可用性以及（2）他们利用社交活动的倾向信息。对于年龄的影响，我们发现两种类型的刺激都具有一致的结果：青少年更有可能接触刺激并探索更长的时间。同样，对于这两个任务，在测试时参与某项活动的个人接触刺激的可能性较小，并且探索时间较短。最后，青少年和女性倾向于使用社交信息（例如被盗用）接触纸袋的可能性更高，等待时间更短。我们的发现不仅突显了野外进行的认知研究可能存在的偏见，而且突显了决定任务参与程度的一些个体属性和外部因素。