Abstract: Bloodletting—the practice of letting blood out to cure a patient—was for centuries one of the main therapies in the West. We lay out three potential explanations for bloodletting’s cultural success: that it was efficient, that it was defended by prestigious sources—in particular ancient physicians—, and that cognitive mechanisms made it a particularly attractive practice. To test these explanations, we first review the anthropological data available in eHRAF. These data reveal that bloodletting is practiced by many unrelated cultures worldwide, where it is performed for different indications and in different ways. This suggests that the success of bloodletting cannot only be explained by its medical efficiency or by the prestige of Western physicians. Instead, some universal cognitive mechanisms likely make bloodletting an attractive form of therapy. We further test this hypothesis using the technique of transmission chains. Three experiments are conducted in the U.S., a culture that does not practice bloodletting. Studies 1 and 2 reveal that stories involving bloodletting survive longer than some other common therapies, and that the most successful variants in the experiments are also the most successful variants worldwide. Study 3 shows how a story about a mundane event—an accidental cut—can turn into a story about bloodletting. This research demonstrates the potential of combining different methodologies—review of anthropological data, experiments, and modeling—to investigate cultural phenomena.
Claidière, N., Smith, K., Kirby, S., & Fagot, J. (2014). Cultural evolution of systematically structured behaviour in a non-human primate. Proceedings of the Royal Society B: Biological Sciences, 281(1797). doi: 10.1098/rspb.2014.1541
Abstract: Culture pervades human life and is at the origin of the success of our species. A wide range of other animals have culture too, but often in a limited form that does not complexify through the gradual accumulation of innovations. We developed a new paradigm to study cultural evolution in primates in order to better evaluate our closest relatives’ cultural capacities. Previous studies using transmission chain experimental paradigms, in which the behavioural output of one individual becomes the target behaviour for the next individual in the chain, show that cultural transmission can lead to the progressive emergence of systematically structured behaviours in humans. Inspired by this work, we combined a pattern reproduction task on touch screens with an iterated learning procedure to develop transmission chains of baboons (Papio papio). Using this procedure, we show that baboons can exhibit three fundamental aspects of human cultural evolution: a progressive increase in performance, the emergence of systematic structure and the presence of lineage specificity. Our results shed new light on human uniqueness: we share with our closest relatives essential capacities to produce human-like cultural evolution.
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Claidière, N., Scott-Phillips, T. C., & Sperber, D. (2014). How Darwinian is cultural evolution? Philosophical Transactions of the Royal Society B: Biological Sciences, 369(1642). doi: 10.1098/rstb.2013.0368
Abstract: Darwin-inspired population thinking suggests approaching culture as a population of items of different types, whose relative frequencies may change over time. Three nested subtypes of populational models can be distinguished: evolutionary, selectional and replicative. Substantial progress has been made in the study of cultural evolution by modelling it within the selectional frame. This progress has involved idealizing away from phenomena that may be critical to an adequate understanding culture and cultural evolution, particularly the constructive aspect of the mechanisms of cultural transmission. Taking these aspects into account, we describe cultural evolution in terms of cultural attraction, which is populational and evolutionary, but only selectional under certain circumstances. As such, in order to model cultural evolution, we must not simply adjust existing replicative or selectional models, but we should rather generalize them, so that, just as replicator-based selection is one form that Darwinian selection can take, selection itself is one of several different forms that attraction can take. We present an elementary formalization of the idea of cultural attraction.
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Abstract: Modes of cultural transmission are, by analogy with modes of genetic transmission, ways in which cultural information is transmitted between individuals. Despite its importance across the behavioral sciences and for theories of cultural evolution, no attempts have been made, to our knowledge, to critically analyze this analogy. We here aim at such detailed comparison and show that the fundamental role of modes of transmission in biology results mainly from two properties of genetic transmission: (i) what is transmitted generally does not influence the way in which it is transmitted; (ii) there is a limited number of simple and stable modes. In culture however, modes of transmission generally lack these two fundamental properties. In particular, in culture it is often the rate of evolutionary change that determines the mode of transmission. We offer some tentative explanation regarding the origins of such a fundamental difference and we conclude that cultural transmission modes are not causal mechanisms that govern the transmission of culture but mere descriptions of the way culture happens to be transmitted at a given time in a given community. This shows the limit of the analogy between biological and cultural evolution and suggests that evolutionary models and theories differ substantially between the two domains.
Conformity, defined here by the fact that an individual displays a particular behavior because it is the most frequent they witnessed in others, has long been recognized by social psychologists as one of the main categories of social influence. Surprisingly, it is only recently that conformity has become an active topic in animal and evolutionary biology. As in any new and rapidly growing field however, definitions, hypotheses and protocols are diverse, not easy to organize in a coherent way and sometimes seriously conflict with each other. Here we pursue greater coherence by reviewing the newer literature on conformity in behavioral ecology and evolutionary biology in light of the foundational work in social psychology. We suggest that the knowledge accumulated in social psychology can be exploited by behavioral ecologists and evolutionary biologists to bring conceptual clarity to the field, avoid some experimental pitfalls and help design new and challenging experiments. In particular, we propose that the notions of ‘informational’ and ‘normative’ conformity that, until now, have not been recognized in recent literature can resolve some important controversies. In turn, research on animal culture should be of great interest to social scientists, because understanding human culture and human uniqueness requires an evolutionary analysis of our cognitive capacities and their evolutionary origins. Our review suggests excellent opportunities for social and natural scientists to join forces in building an interdisciplinary and integrative approach to the pervasive phenomenon of conformity.
For acquired behaviour to count as cultural, two conditions must be met: it must propagate in a social group, and it must remain stable in the process of propagation. It is commonly claimed that imitation is the mechanism that explains both the spread of animal culture and its persistence. We review the literature on transmission chain studies in chimpanzees and other animals. We use a formal model to argue, that imitation, which may well play a major role in the propagation of animal culture, cannot be considered faithful enough to explain its stability. We show that adding to the capacity for imitation a relatively strong conformist tendency of the kind suggested by Boyd and Richerson is relevant but unlikely to be sufficient. We consider the contribution that other psychological or ecological factors might make to the persistence of animal culture observed in the wild.