Spontaneous (minimal) ritual in non-human great apes?

What we know and don't know about great ape cultural communication in the wild

Following the first descriptions of culture in primates, widespread agreement has developed that the term can be applied to nonhumans as group-specific, socially learned behaviors. While behaviors such as those involving extractive tool use have been researched intensively, we propose that behaviors that are more subtle, less likely to be ecologically constrained, and more likely to be socially shaped, such as cultural forms of communication, provide compelling evidence of culture in nonhuman primates. Additionally, cultural forms of communication can provide novel insights into animal cognition such as the capacity for conformity, conventionalized meanings, arbitrariness in signal forms, and even symbolism. In this paper we focus on evidence from studies conducted on wild great apes. First, we provide a thorough review of what exactly we do know, and by extension don't know, about great ape cultural communication. We argue that detailed research on both vocal and gestural communication in wild great apes shows a more nuanced and variable repertoire than once assumed, with increasing support for group-specific variation. Second, we discuss the relevance of great ape cultural communication and its potential for illustrating evolutionary continuity for human-like cultural attributes, namely cumulative culture and symbolism. In sum, a concerted effort to examine cultural forms of communication in great apes could reveal novel evidence for cultural capacities that have thus far been heavily debated in the literature and can simultaneously contribute to an improved understanding of the complex minds of our closest living relatives.

Clarifying Misconceptions of the Zone of Latent Solutions Hypothesis: A Response to Haidle and Schlaudt: Miriam Noël Haidle and Oliver Schlaudt: Where Does Cumulative Culture Begin? A Plea for a Sociologically Informed Perspective (Biological Theory 15: 161-174, 2020)

The critical examination of current hypotheses is one of the key ways in which scientific fields develop and grow. Therefore, any critique, including Haidle and Schlaudt's article, "Where Does Cumulative Culture Begin? A Plea for a Sociologically Informed Perspective," represents a welcome addition to the literature. However, critiques must also be evaluated. In their article, Haidle and Schlaudt (Biol Theory 15:161-174, 2020. 10.1007/s13752-020-00351-w; henceforth H&S) review some approaches to culture and cumulative culture in both human and nonhuman primates. H&S discuss the "zone of latent solutions" (ZLS) hypothesis as applied to nonhuman primates and stone-toolmaking premodern hominins. Here, we will evaluate whether H&S's critique addresses its target.

Ritual explained: interdisciplinary answers to Tinbergen's four questions

Convergent developments across social scientific disciplines provide evidence that rituals are a psychologically prepared and culturally inherited behavioural hallmark of our species. The dramatic diversity of ritual practices ranges from simple greetings to elaborate religious ceremonies, from the benign to life-threatening. Yet our scientific understanding of this core human trait remains limited. Explaining the universality, functionality and diversity of ritual requires insight from multiple disciplines. This special issue integrates research from anthropology, archaeology, biology, primatology, cognitive science, psychology, religious studies and demography to build an interdisciplinary account of ritual. The objective is to contribute to an integrative explanation of ritual by addressing Tinbergen's four key questions. These include answering ultimate questions about the (i) phylogeny and (ii) adaptive functions of ritual; and proximate questions about the (iii) mechanisms and (iv) ontogeny of ritual. The intersection of these four complementary lines of inquiry yields new avenues for theory and research into this fundamental aspect of the human condition, and in so doing, into the coevolution of cognition and culture. This article is part of the theme issue 'Ritual renaissance: new insights into the most human of behaviours'.

The zone of latent solutions and its relevance to understanding ape cultures

The zone of latent solutions (ZLS) hypothesis provides an alternative approach to explaining cultural patterns in primates and many other animals. According to the ZLS hypothesis, non-human great ape (henceforth: ape) cultures consist largely or solely of latent solutions. The current competing (and predominant) hypothesis for ape culture argues instead that at least some of their behavioural or artefact forms are copied through specific social learning mechanisms ("copying social learning hypothesis") and that their forms may depend on copying (copying-dependent forms). In contrast, the ape ZLS hypothesis does not require these forms to be copied. Instead, it suggests that several (non-form-copying) social learning mechanisms help determine the frequency (but typically not the form) 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 (cued) 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 (provided sufficient opportunity, necessity, motivation and timing). 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 (and/or artefact) 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.