Lydia Hopper

Social norms – rules governing which behaviours are deemed appropriate or inappropriate within a given community – are typically taken to be uniquely human. Recently, this position has been challenged by a number of philosophers, cognitive scientists, and ethologists, who have suggested that social norms may also be found in certain non-human animal communities. Such claims have elicited considerable scepticism from norm cognition researchers, who doubt that any non-human animals possess the psychological capacities necessary for normative cognition. However, there is little agreement among these researchers about what these psychological prerequisites are. This makes empirical study of animal social norms difficult, since it is not clear what we are looking for and thus what should count as behavioural evidence for the presence (or absence) of social norms in animals. To break this impasse, we offer an approach that moves beyond contested psychological criteria for social norms. This approach is inspired by the animal culture research program, which has made a similar shift away from heavily psychological definitions of ‘culture’ and to become organized around a cluster of more empirically tractable concepts of culture. Here, we propose an analogous set of constructs built around the core notion of a normative regularity, which we define as a socially maintained pattern of behavioural conformity within a community. We suggest methods for studying potential normative regularities in wild and captive primates. We also discuss the broader scientific and philosophical implications of this research program with respect to questions of human uniqueness, animal welfare and conservation.

The zone of latent solutions hypothesis provides an alternative approach to explaining cultural patterns in primates and many other animals. According to the ZLS hypothesis, non-human great ape cultures consist largely or solely of latent solutions. The current competing hypothesis for ape culture argues instead that at least some of their behavioural or artefact forms are copied through specific social learning mechanisms and that their forms may depend on copying. In contrast, the ape ZLS hypothesis does not require these forms to be copied. Instead, it suggests that several social learning mechanisms help determine the frequency of these behaviours and artefacts within connected individuals. The ZLS hypothesis thus suggests that increases and stabilisations of a particular behaviour’s or artefact’s frequency can derive from socially-mediated form reinnovations. Therefore, and while genes and ecology play important roles as well, according to the ape ZLS hypothesis, apes typically acquire the forms of their behaviours and artefacts individually, but are usually socially induced to do so. The ZLS approach is often criticized—perhaps also because it challenges the current null hypothesis, which instead assumes a requirement of form-copying social learning mechanisms to explain many ape behavioural forms. However, as the ZLS hypothesis is a new approach, with less accumulated literature compared to the current null hypothesis, some confusion is to be expected. Here, we clarify the ZLS approach—also in relation to other competing hypotheses—and address misconceptions and objections. We believe that these clarifications will provide researchers with a coherent theoretical approach and an experimental methodology to examine the necessity of form-copying variants of social learning in apes, humans and other species.

Consideration of social cognition—how an individual’s decision-making is influenced by her/his social environment—is key to understanding the behaviour of socially living nonhuman primates. In this chapter we discuss primate social cognition by focusing on primates’ behavioural responses to the presence and actions of others, how they adjust their behaviour to maximize their own gains, and possibly also the rewards received by a partner. Individuals can observe and replicate the actions of others, or the outcomes of their actions, to accelerate behavioural acquisition of techniques to obtain rewards. Beyond passively observing others, primates can also work with group mates to obtain rewards more easily or to get rewards that would otherwise be unattainable by a single individual. Although not universally seen among primates, one individual may also help another to acquire resources. Prosocial and collaborative interactions may result in an imbalance of benefits received, and certain primate species respond negatively when receiving less than a social partner, a response which may protect individuals against cheating. Such behaviours demonstrate how the interplay between an individual’s desires and those of others can modify behavioural outcomes and the importance of considering cognition from a social perspective in order to understand the decision-making of individuals. However, there is variation both within and between species in their sensitivity to the actions of others and their responses to them. Thus, a comparative framework is needed when studying what is meant by ‘primate social cognition’.