Traditionally, primate cognition research has been conducted by independent teams on small populations of a few species. Such limited variation and small sample sizes pose problems that prevent us from reconstructing the evolutionary history of primate cognition. In this chapter, we discuss how large-scale collaboration, a research model successfully implemented in other fields, makes it possible to obtain the large and diverse datasets needed to conduct robust comparative analysis of primate cognitive abilities. We discuss the advantages and challenges of large-scale collaborations and argue for the need for more open science practices in the field. We describe these collaborative projects in psychology and primatology and introduce ManyPrimates as the first, successful collaboration that has established an infrastructure for large-scale, inclusive research in primate cognition. Considering examples of large-scale collaborations both in primatology and psychology, we conclude that this type of research model is feasible and has the potential to address otherwise unattainable questions in primate cognition.

Cognition is the use of information to solve problems, and the evolution of cognition is the natural history of the application of problem-solving capacities to adaptive problems. The ecological contexts in which primates apply their cognitive capacities vary substantially, and therefore the specific problems pertaining to fitness – finding mates, finding food, predator avoidance, and so forth – elicit systematic patterns of comportment through these different environments. A central debate in comparative cognition concerns the degree to which cognitive abilities are shaped by natural selection: this is the question of whether any given problem-solving skill reflects the application of domain-general or domain-specific cognitive capacities. The debate over whether the demands of foraging or the complexity of the social environment exerts the greater force on brain evolution and behavior exemplifies that the kinds of questions that can be asked about cognitive evolution significantly depend on one’s prior commitment to the domain-specificity of adaptive behavior. It remains a relatively open question whether there are cognitive specializations for navigating the physical world that are qualitatively distinct from specializations for navigating the social world. There is a panoply of investigative methods for eliciting problem-solving behavior in captive populations of primates, but there is also an emerging tension between proponents of ecological and internal validity, respectively. Here, I will argue that artificial, captive environments are, nevertheless, ecologically comprised and that the study of captive animals follows a long tradition of perturbation studies in ethology. I will finish with a number of case studies of primate cognition from both wild and captive environments.

Semantic communication is about transmitting mental representations of reality. Three research questions address the nature of this process in primates. Can primates produce signals that are meaningful in a lexical sense? Are they capable of compositional semantics? Can they create and infer meaning by integrating context and intention? There is good evidence that, as recipients, primates have capacities at all three levels, whereas for signallers the evidence is less compelling. This difference may have cognitive roots, due to the fact that primate signallers are typically engaged in the here-and-now and, unlike humans, less able to refer to memory content. Future research will have to clarify what mental structures primates can take into account during communication, including entities that are not physically present.