Opportunities and mechanisms for learning through social interactions: lessons from marmosets.

Social interactions are crucial for learning not only in humans but also in non-human animals. To date, comparative studies have typically focused on what is learned from others and on purely observational learning, while paying less attention on how social interactions facilitate learning. Here, we present how computational approaches can be leveraged to examine the role of contingency in learning through social interactions, focusing on callitrichid monkeys. They are the only primates besides humans in which group members other than the mother contribute significantly to infant care (i.e. cooperative breeding), resulting in more and richer opportunities for social interactions and learning, in both immatures and adults. We first review how contingency, turn-taking and social timing fundamentally shape learning and inter-individual coordination. We then zoom in on turn-taking in vigilance and vocal accommodation, illustrating how mathematical modelling can offer unique insights into the underlying mechanisms. We also highlight the potential of hybrid approaches that combine machine learning's pattern detection strengths with the interpretability and explanatory power of mathematical models. Overall, we find that contingency is key to learning through social interactions not only in humans but also in non-human primates, and perhaps particularly so in the cooperatively breeding callitrichids. This article is part of the theme issue 'Mechanisms of learning from social interaction'.