Paradox of diversity in the collective brain

Human societies are collective brains. People within every society have cultural brains—brains that have evolved to selectively seek out adaptive knowledge and socially transmit solutions. Innovations emerge at a population level through the transmission of serendipitous mistakes, incremental improvements and novel recombinations. The rate of innovation through these mechanisms is a function of (1) a society's size and interconnectedness (sociality), which affects the number of models available for learning; (2) fidelity of information transmission, which affects how much information is lost during social learning; and (3) cultural trait diversity, which affects the range of possible solutions available for recombination. In general, and perhaps surprisingly, all three levers can increase and harm innovation by creating challenges around coordination, conformity and communication. Here, we focus on the ‘paradox of diversity’—that cultural trait diversity offers the largest potential for empowering innovation, but also poses difficult challenges at both an organizational and societal level. We introduce ‘cultural evolvability’ as a framework for tackling these challenges, with implications for entrepreneurship, polarization and a nuanced understanding of the effects of diversity. This framework can guide researchers and practitioners in how to reap the benefits of diversity by reducing costs. This article is part of a discussion meeting issue ‘The emergence of collective knowledge and cumulative culture in animals, humans and machines’.

Hidden Clusters Beyond Ethnic Boundaries

Hidden cluster problems can manifest when broad ethnic categories are used as proxies for cultural traits, especially when traits are assumed to encode cultural distances between groups. We suggest a granular understanding of cultural trait distributions within and between ethnic categories is fundamental to the interpretation of heritability estimates as well as general behavioral outcomes.

Vodun Continuum in Black America: Communication with the Dead and the Invisible World in Jesmyn Ward’s Sing Unburied Sing

The spread of Western rationalism through armed conquest, with the global dominance of Judeo-Christian and Islamic creeds, has almost obliterated the existence of the alternative ontological perceptions rooted in the dominated people’s cultures. This essay studies how Ward’s Sing Unburied Sing reaches back to African ancestral beliefs, vodun practices and rituals, and brings to life characters who strive to counteract exclusion with the conception of the world as a Whole, a continuum whose survival is premised on the respect of, and fusional union with, each element of that Whole. This conception partakes in the search for meaning to existence in a society that has erected individualism and the exclusion of black people into creed. The paper uses the theoretical approach of vodun ontology and, in an Afrocentric perspective, reads through Ward’s novel this cultural trait thriving centuries after the enslaved people’s departure from Africa. It purports to voice African traditional values and to celebrate cultural difference.

Tradition and Trade: Culture and Exploitation of Avian Fauna by a Rural Community Surrounding Protected Areas in the South of Bahia’s State, Northeastern Brazil

Background: Illegal capture and trade of wild birds are some of the most present types of wildlife trade in Brazil, and are often associated with cultural and socioenvironmental aspects. Those habits are particularly present in rural communities, where bird trade can be a source of income in dire economic situations and bird-keeping is a cultural trait passed from generations. Methods: We conducted a series of direct interviews with bird-keepers and traders within the surrounding region of the Parque Nacional de Boa Nova regarding wild bird trade and socioenvironmental aspects, then associated the collected information using different exploratory analysis.Results: A total of 21 avian species was mentioned as being used as pets and in commercialization, contests and breeding, most of the occurring naturally in the surrounding region. Most respondents were men possessing low levels of education and income. Bird-keeping was surrounded by practices regarding the captive individual’s health and singing abilities. Mentioned methods used to capture wild birds often involved specialized traps and were mostly conducted within the national park’s area. Bird trade was said to occur mostly in urban settlements, and the value of captive birds was said to vary based on species and beforehand training. The official establishment of the protected area impaired all practices related bird-keeping and trade, mostly as a result of increased surveillance by environmental agencies.Conclusion: The collected information presents a series of specialized habits and practices involved in bird-keeping, bird capture and bird trade, many of them being associated with the local avifauna surrounding the region. Our study also points the efficiency of protected area surveillance to contain practice’s related to illegal wildlife trade.

Ornament, armament, or toolkit? Modelling how population size drives the evolution of birdsong, a functional cultural trait

Oscine songbirds have been an important study system for social learning, particularly because their learned songs provide an analog for human languages and music. Here we propose a different analogy; from an evolutionary perspective, could a bird’s song be more like an arrowhead than an aria? We modify an existing model of human tool evolution to accommodate cultural evolution of birdsong: each song learner chooses the most skilled available tutor to emulate, and more likely produces an inferior copy than a superior one. Similarly to human toolx evolution, we show that larger populations foster greater improvements in song over time, even when learners restrict their pool of tutors to a subset of individuals. We also demonstrate that randomly sampling tutors from the population offers no clear benefit over sampling only existing connections in a structured social network, and that by allowing a lower quality trait to be easier to imitate than a higher quality one, simpler songs can be maintained after population bottlenecks. We show that these processes could plausibly generate empirically observed patterns of song evolution, and we make predictions about the types of song elements most likely to be lost when populations shrink. More broadly, we aim to connect the modeling approaches used by researchers studying social learning in human and non-human systems, moving toward a cohesive theoretical framework that accounts for both cognitive and demographic processes.

Hospitality and exchange: Identity relationships between ‘natives’ and ‘foreigners’ in Sardinia

Islands have frequently been invoked as a central topos of anthropological inquiry. The idea that islands and their inhabitants were isolated from the rest of the world led to them being treated as living laboratories, ripe for the investigation of a supposed cultural and biological purity. In contrast, the history of Sardinia shows how the island and its inhabitants have historically demonstrated agency in their relationships within the Mediterranean space and beyond. Moving from the assumption that a social group elaborates its identity by experiencing the ‘other’, I use the concept of hospitality as a theoretical framework for its ability to encompass complex and correlated questions helpful in thinking about individuals’ and societies’ relationships with ‘intimacy’ and ‘otherness’. Following this perspective, the contribution aims to examine how, in Sardinia, practices of hospitality have been involved in shaping a feeling of belonging that, in this case, could be called ‘Sardinian-ness’. Specifically, I investigate how global phenomena such as mass tourism and transnational migration impact and change the cultural trait of traditional hospitality, and how these phenomena unfold in an insular context.

Evoked and Transmitted Culture models: Using bayesian methods to infer the evolution of cultural traits in history

A central question in behavioral and social sciences is understanding to what extent cultural traits are inherited from previous generations, transmitted from adjacent populations or produced in response to changes in socioeconomic and ecological conditions. As quantitative diachronic databases recording the evolution of cultural artifacts over many generations are becoming more common, there is a need for appropriate data-driven methods to approach this question. Here we present a new Bayesian method to infer the dynamics of cultural traits in a diachronic dataset. Our method called Evoked-Transmitted Cultural model (ETC) relies on fitting a latent-state model where a cultural trait is a latent variable which guides the production of the cultural artifacts observed in the database. The dynamics of this cultural trait may depend on the value of the cultural traits present in previous generations and in adjacent populations (transmitted culture) and/or on ecological factors (evoked culture). We show how ETC models can be fitted to quantitative diachronic or synchronic datasets, using the Expectation-Maximization algorithm, enabling estimating the relative contribution of vertical transmission, horizontal transmission and evoked component in shaping cultural traits. The method also allows to reconstruct the dynamics of cultural traits in different regions. We tested the performance of the method on synthetic data for two variants of the method (for binary or continuous traits). We found that both variants allow reliable estimates of parameters guiding cultural evolution. Overall, our method opens new possibilities to reconstruct how culture is shaped from quantitative data, with possible application in cultural history, cultural anthropology, archaeology, historical linguistics and behavioral ecology.

The Formation of Social Network Assortativity: A Cultural Trait-Matching Mechanism

The preferential attachment mechanism that forms scale-free network cannot display assortativity, i.e., the degree of one node is positively correlated with that of their neighbors in the network. Given the attributes of network nodes, a cultural trait-matching mechanism is further introduced in this paper. Both theoretical analysis and simulation results indicate that the higher selection probability of such mechanism, the more obvious the assortativity is shown in networks. Further, the degree of nodes presents a positive logarithm correlation with that of adjacent ones. Finally, this study discusses the theoretical and practical significances of the introduction of such a cultural trait-matching mechanism.

Behavioural diversity of bonobo prey preference as a potential cultural trait

The importance of cultural processes to behavioural diversity in our closest living relatives is central to revealing the evolutionary origins of human culture. However, the bonobo is often overlooked as a candidate model. Further, a prominent critique to many examples of proposed animal cultures is premature exclusion of environmental confounds known to shape behavioural phenotypes. We addressed these gaps by investigating variation in prey preference between neighbouring bonobo groups that associate and overlap space use. We find group preference for duiker or anomalure hunting otherwise unexplained by variation in spatial usage, seasonality, or hunting party size, composition, and cohesion. Our findings demonstrate that group-specific behaviours emerge independently of the local ecology, indicating that hunting techniques in bonobos may be culturally transmitted. The tolerant intergroup relations of bonobos offer an ideal context to explore drivers of behavioural phenotypes, the essential investigations for phylogenetic constructs of the evolutionary origins of culture.