Claudio Tennie

Human ritual is difficult to trace directly in deep time. We approach its evolutionary origins indirectly by asking when the necessary cognitive prerequisites for ritual were first plausibly present in the archaeological record – to impose a terminus post quem for true ritual. We argue that true ritual, unlike mere “ritualized” biological behaviour and unlike possible precursors, requires know-how copying: the causal reproduction of behavioural and/or artefactual forms derived from the observation of models, which crucially includes forms that individuals would not realistically perform without having observed such models. Because spontaneous know-how copying in non-human great apes is nearly or completely absent, ritual was probably not inherited from our last common ancestor. We therefore look to the hominin archaeological record. We argue that the earliest stone tools – and especially the Oldowan - did not require know-how copying, and so do not by themselves positively evidence the necessary cognitive capacity required for true ritual. However, this cognitive capacity may become apparent in the middle to late Acheulean, roughly 800,000–500,000 years ago, when knapped stone forms become more diverse and complex, and where their underlying know-how cannot parsimoniously be explained in other ways. That is, the middle to late Acheulean positively evidence for the first type(s) of know-how copying, and as a result, we suggest this period as the earliest plausible window the necessary cognitive faculties required for true ritual. The inferred presence of know-how copying at these times suggests the last common ancestor of humans, Neanderthals and Denisovans, were the first plausible candidates for the earliest true ritual. We leave open the possibility that true ritual may also require symbolism as another key element, though we speculate that symbolism may have emerged more recently, perhaps between 500,000 and 150,000 years ago. If so, full true ritual should be sought mainly within that later bracket. Our dates are not presented as final, but as a cognitive-archaeologically derived guide for narrowing the search. These dates may change in the future with new primatological or archaeological evidence or when new types of analysis become available.

By rewarding speed, volume, and coherent positive narratives, traditional publishing incentivizes questionable scientific practices and analytic flexibility. The latter especially contributes to blurring the distinction between exploration and confirmation, which inflates the apparent strength of confirmatory claims. This systemic issue has gone unchecked for decades, leaving the scientific community with a body of scholarly literature that is unreliable and lacking validity. Registered Reports (RRs) address problematic publishing practices by requiring a priori registration of confirmatory tests, which is peer-reviewed before the research begins (stage 1). The editorial acceptance of a stage 1 plan establishes a commitment to publication regardless of research outcomes. Publication remains, nonetheless, contingent on a second peer review and editorial scrutiny (stage 2) to verify that the approved plan was followed, all deviations were transparently disclosed and justified, confirmatory and exploratory claims are clearly delineated, and the integrity of the design was maintained. Meta-scientific comparisons indicate that RRs reduce outcome-based publication bias and improve methodological rigor without compromising perceived novelty. By making accepted RR protocols and their review history citable research outputs, RRs also strengthen recognition for peer-review work. In this perspective, we argue that RRs should become the primary mode of confirmatory publication moving forward.

Stage 2 of Chater and Christiansen’s (henceforth CC) model involves the ability to copy. Our comment concerns not the order of copying in CC’s model, but their time estimate of its origins. CC treat copying as present in apes and implied by early stone tools, and hence (presumably) had by the last common ancestor. Here we argue for a later onset.

Understanding the evolutionary origins of combinatorial communication has motivated studies that analyse the semantic capacities of great ape vocal repertoires. A prominent example is the study by Berthet et al. (2025), which used Multiple Correspondence Analysis (MCA) on a large multidimensional dataset of bonobo calls and concluded that certain call combinations exhibit compositional meaning. We applied the published analytical pipeline to randomized datasets lacking any genuine association between call types and contextual features. Depending on implementation choices, the procedure identified significant relationships in 34.5–84.3% of simulations, suggesting substantial inflation of false-positive results. We therefore re-examined the statistical assumptions underlying the analysis itself. Because the MCA was constructed from repeated measures and uneven sampling across call types, its geometry reflects sampling frequencies and hierarchical dependencies in addition to any semantic structure. As such, any subsequent linear modelling of distances within this fixed space further violates assumptions of independence. We introduced a full permutation test in which a weighted MCA is recomputed under random reassignment of call-type labels, thereby generating a null distribution that respects the dependence structure of the data. Applying this procedure to the original dataset yielded a non-significant Monte Carlo p -value ( p = 0.2597), indicating that the observed between-call-type separation does not exceed chance expectations. We argue that interpreting MCA distances as semantic relations requires theoretically motivated feature selection and dependence-aware inference, both of which are lacking in the original analysis. We conclude that Berthet et al. (2025) do not provide any statistically significant evidence for bonobo compositionality and highlight the broader limitations of relying on exploratory post-hoc statistical inference to identify semantic structure in animal communication.

Mid-last century, controversy existed around the question whether non-human great apes have culture. To a large degree, this is no longer controversial – apes have their own cultures. However, there remains controversy around how to best study ape culture, given the varying and often dichotomised contributions from captive and field-ape research. Here, we present a historical summary of the ape culture wars since their inception and how this has evolved over time. We then focus on debates surrounding wild versus captive-ape research with an emphasis on culture, detailing major arguments arising from both research domains. Throughout, we critically deconstruct these arguments, illustrating the nuance behind these critiques, while highlighting their assumptions, overgeneralising statements and potential constraints. We further provide potential solutions to help alleviate the issues we describe, when possible. We also offer a metacritique of ape culture research for its scientific and political impact, irrespective of one’s expertise. In closing, we summarise concrete recommendations for a richer and more holistic understanding of ape, and human, culture.

Despite growing consensus that cognitive differences between Neanderthals and modern humans were not as significant as once assumed, visual art remains disproportionately associated with Homo sapiens . This paper explores why that is. Rather than appealing to underlying cognition, we argue that early art was pushed and pulled by social dynamics and demographic contexts on a larger scale and eventually formed through cultural transmission. Drawing on the archaeological record, we focus on pigment use, ornamentation, engravings and painting. We suggest that these practices initially remained ad hoc while still functioning as tools for social signalling and intergroup communication in the small-scale communities of Neanderthals and early modern humans. We argue that visual art moved beyond ad hoc practices under conditions of increased population density and interaction – first via the crystallization of art as a tradition and second, as cumulative cultural art. Lack of cognitive ability is not a well-supported explanation for the empirical low frequency of Neanderthal art. Instead, we propose effects of differences in social connectivity and population densities as an alternative. By reframing art as a flexible, context-dependent behaviour, we challenge essentialist models and advocate for a pluralistic view of cognitive and cultural expression across different hominin groups.

Whether and how dolphins can engage in spontaneous, untrained social learning to solve novel tool problems via action- or result- (or other) social learning remains debated. In the present study we tested the spontaneous social learning abilities of six dolphins (all not trained to copy) on two tool-using tasks (what we call the ball-up / ball-down task) - using a dolphin demonstrator and a human demonstrator. Regardless of task type and demonstrator type none of the tested dolphins reproduced the demonstrated tool solutions. We experienced several issues regarding our test apparatus, and so these negative results may be due to apparatus failures. However, these findings may also fully or partially indicate that untrained dolphins are not generalized, spontaneous social learners across information types, especially regarding the acquisition of tool solutions in puzzle tasks. More studies are required to precisely determine the capacity for spontaneous tool solution copying in dolphins.

Compared to other apes, humans show a distinctive capacity for the cultural learning and transmission of know-how: we extract know-how from other individuals and artifacts in ways that regularly give rise to forms of know-how that no single individual could realistically invent on their own. Such a capacity is plausibly foundational to humans’ striking cultural prowess and hence all that goes with it (e.g., symbolic language, religion). In this article, we critically examine attempts to date the transformation of know-how copying in the hominin lineage through an estimation of the costs of stone toolmaking. More specifically, we take as our target the idea that the costs inherent in making early stone tools, that is, Oldowan and Early Acheulean tools, already likely reflect a meaingful upgrade in hominin know-how copying abilities. Our survey of potentially relevant costs of stone toolmaking is generous, covering: (i) the risks and dangers of toolmaking; (ii) the time, energy, and opportunity costs of toolmaking; and finally (iii) the material costs of toolmaking. Ultimately, we find that, based on current evidence pertaining to these costs, the case for inferring know-how copying abilities in Oldowan or even Early Acheulean stone toolmakers is weak. This skeptical conclusion, combined with independent evidence that the design of stone tools during this period likely remained within the range of what the relevant hominins could invent without know-how copying, points to a later date for the establishment of this crucial human skill.