Joint evolution of traits for social learning

Abstract

Abstract: Animals vary in the sophistication of their capacities for social learning, and much research has focused on establishing when learning from others is favourable. However, social learning involves both a receiver (who learns), and a sender (who is learned from). Surprisingly, the joint evolution of traits for social learning has attracted little attention, even though learning by the receiver has consequences for the fitness of the sender. Accordingly, animals are observed to teach and mask, and thereby influence available information. Here, we provide a mathematical model to examine when reliable social learning emerges as a result of investment in traits for social and asocial learning, as well as teaching and masking. Our purpose is to provide a general framework for thinking about how social learning is impacted by sender-receiver joint evolution, so our model is heuristic; its aim is to delineate broad categories of direct and indirect selection on learning traits. Our findings lead us to theorise that social learning exists on a continuum. At one extreme, senders and receivers have strongly opposed interests, selecting for masking to combat informational parasitism; at the other extreme, strongly aligned interests lead to teaching to enhance social learning. Sophisticated, metabolically expensive traits for influencing social learning can evolve under either aligned or opposed interests, although the aim of their design differs. Furthermore, we find that traits for asocial learning should often be more sophisticated than traits for receiving, while receiving traits should often be more sophisticated than sender traits for teaching or masking. Significance statement: Learning from group members is often crucial for survival, with social learning influencing the development of behaviours in domains as diverse as foraging, mate preference, and predator defence. Formal modelling has provided a good understanding of the conditions that favour social learning, given animals already have the ability to learn asocially. However, the success of social learning also depends on the behaviour of the group member who is learned from. For instance, group members may teach others how to hunt dangerous prey. Alternatively, knowledgeable individuals sometimes take actions to hinder learning, for instance, by disguising the location of a food cache. Here, we provide a unitary mathematical framework to study how behaviours of the group member who is learned from jointly evolve with those of the learner. Show more