scholarly journals Cumulative cultural evolution, population structure and the origin of combinatoriality in human language

Author(s):  
Simon Kirby ◽  
Monica Tamariz

Language is the primary repository and mediator of human collective knowledge. A central question for evolutionary linguistics is the origin of the combinatorial structure of language (sometimes referred to as duality of patterning), one of language’s basic design features. Emerging sign languages provide a promising arena to study the emergence of language properties. Many, but not all such sign languages exhibit combinatoriality, which generates testable hypotheses about its source. We hypothesize that combinatoriality is the inevitable result of learning biases in cultural transmission, and that population structure explains differences across languages. We construct an agent-based model with population turnover. Bayesian learning agents with a prior preference for compressible languages (modelling a pressure for language learnability) communicate in pairs under pressure to reduce ambiguity. We include two transmission conditions: agents learn the language either from the oldest agent or from an agent in the middle of their lifespan. Results suggest that (1) combinatoriality emerges during iterated cultural transmission under concurrent pressures for simplicity and expressivity and (2) population dynamics affect the rate of evolution, which is faster when agents learn from other learners than when they learn from old individuals. This may explain its absence in some emerging sign languages. We discuss the consequences of this finding for cultural evolution, highlighting the interplay of population-level, functional and cognitive factors. This article is part of a discussion meeting issue ‘The emergence of collective knowledge and cumulative culture in animals, humans and machines’.

2021 ◽  
Author(s):  
Mason Youngblood ◽  
David Lahti

In this study, we used a longitudinal dataset of house finch (Haemorhous mexicanus) song recordings spanning four decades in the introduced eastern range to assess how individual-level cultural transmission mechanisms drive population-level changes in birdsong. First, we developed an agent-based model (available as a new R package called TransmissionBias) that simulates the cultural transmission of house finch song given different parameters related to transmission biases, or biases in social learning that modify the probability of adoption of particular cultural variants. Next, we used approximate Bayesian computation and machine learning to estimate what parameter values likely generated the temporal changes in diversity in our observed data. We found evidence that strong content bias, likely targeted towards syllable complexity, plays a central role in the cultural evolution of house finch song in western Long Island. Frequency and demonstrator biases appear to be neutral or absent. Additionally, we estimated that house finch song is transmitted with extremely high fidelity. Future studies should use our simulation framework to better understand how cultural transmission and population declines influence song diversity in wild populations.


2020 ◽  
Author(s):  
Erik Gjesfjeld ◽  
Enrico R. Crema ◽  
Anne Kandler

One of the most significant challenges for cultural evolution is the inference of macroevolutionary patterns from historical and archaeological sources of cultural data. Here, we examine the utility of diversification rate analysis for observing trends in the mode and tempo of cultural evolution using simulated cultural data sets. We explore a range of scenarios in which transmission modes, population size, and innovation rates change over time and generate population-frequency data. From this data, we extract longitudinal richness and further reduce its completeness through time-averaging and random sampling. Given that perfect population-level frequencies can rarely be assumed or even approximated from historical data, these simulated scenarios provide the grounds for exploring the inferential power of longitudinal richness data. Results suggest that diversification rate analysis can identify profiles of underlying changes in population size, innovation rates, and cultural transmission. Furthermore, our results highlight a series of methodological outcomes that can be used to enhance future research into the dynamic patterns of cultural evolution.


2021 ◽  
Author(s):  
Joseph Michael Stubbersfield

Conspiracy theories have been part of human culture for hundreds of years, if not millennia, and have been the subject of research in academic fields such as Social Psychology, Political Science and Cultural Studies. At present, there has been little research examining conspiracy theories from a Cultural Evolution perspective. This chapter discusses the value of Cultural Evolution approaches to understanding the diffusion of conspiracy theories. Focusing on the role of biases in cultural transmission, it argues that a key advantage of applying a Cultural Evolution approach to this phenomenon is that it provides a strong theoretical and methodological framework to bridge the individual, inter-individual and population level factors that explain the cultural success of conspiracy theories, with potential for producing insights into how to limit their negative influence.


Author(s):  
Alan F. T. Winfield ◽  
Susan Blackmore

This paper presents a series of experiments in collective social robotics, spanning more than 10 years, with the long-term aim of building embodied models of (aspects of) cultural evolution. Initial experiments demonstrated the emergence of behavioural traditions in a group of social robots programmed to imitate each other’s behaviours (we call these Copybots). These experiments show that the noisy (i.e. less than perfect fidelity) imitation that comes for free with real physical robots gives rise naturally to variation in social learning. More recent experimental work extends the robots’ cognitive capabilities with simulation-based internal models, equipping them with a simple artificial theory of mind. With this extended capability we explore, in our current work, social learning not via imitation but robot–robot storytelling, in an effort to model this very human mode of cultural transmission. In this paper, we give an account of the methods and inspiration for these experiments, the experiments and their results, and an outline of possible directions for this programme of research. It is our hope that this paper stimulates not only discussion but suggestions for hypotheses to test with the Storybots. This article is part of a discussion meeting issue ‘The emergence of collective knowledge and cumulative culture in animals, humans and machines’.


2002 ◽  
Vol 2 (2) ◽  
pp. 87-112 ◽  
Author(s):  
Robert Boyd ◽  
Joseph Henrich

AbstractFormal models of cultural evolution analyze how cognitive processes combine with social interaction to generate the distributions and dynamics of 'representations.' Recently, cognitive anthropologists have criticized such models. They make three points: mental representations are non-discrete, cultural transmission is highly inaccurate, and mental representations are not replicated, but rather are 'reconstructed' through an inferential process that is strongly affected by cognitive 'attractors.' They argue that it follows from these three claims that: 1) models that assume replication or replicators are inappropriate, 2) selective cultural learning cannot account for stable traditions, and 3) selective cultural learning cannot generate cumulative adaptation. Here we use three formal models to show that even if the premises of this critique are correct, the deductions that have been drawn from them are false. In the first model, we assume continuously varying representations under the influence of weak selective transmission and strong attractors. We show that if the attractors are sufficiently strong relative to selective forces, the continuous representation model reduces to the standard discrete-trait replicator model, and the weak selective component determines the final equilibrium of the system. In the second model, we assume inaccurate replication and discrete traits. We show that very low fidelity replication of representations at the individual level does not preclude accurate replication at the population level, and therefore, accurate individual-level replication of representations is not necessary for either cultural inertia or cumulative cultural adaptation. In the third model, we derive plausible conditions for cumulative adaptive evolution, assuming continuous cultural representations, incomplete transmission and substantial inferential transformations.


2018 ◽  
Author(s):  
Alex Mesoudi

Cultural evolution is a branch of the evolutionary sciences which assumes that (i) human cognition and behaviour is shaped not only by genetic inheritance, but also cultural inheritance (also known as social learning), and (ii) this cultural inheritance constitutes a Darwinian evolutionary system that can be analysed and studied using tools borrowed from evolutionary biology. In this chapter I explore the numerous compatibilities between the fields of cultural evolution and cultural psychology, and the potential mutual benefits from their closer alignment. First, understanding the evolutionary context within which human psychology emerged gives added significance to the findings of cultural psychologists, which reinforce the conclusion reached by cultural evolution scholars that humans inhabit a ‘cultural niche’ within which the major means of adaptation to difference environments is cultural, rather than genetic. Hence, we should not be surprised that human psychology shows substantial cross-cultural variation. Second, a focus on cultural transmission pathways, drawing on cultural evolution models and empirical research, can help to explain to the maintenance of, and potential changes in, cultural variation in psychological processes. Evidence from migrants, in particular, points to a mix of vertical, oblique and horizontal cultural transmission that can explain the differential stability of different cultural dimensions. Third, cultural evolutionary methods offer powerful means of testing historical (“macro-evolutionary”) hypotheses put forward by cultural psychologists for the origin of psychological differences. Explanations in terms of means of subsistence, rates of environmental change or pathogen prevalence can be tested using quantitative models and phylogenetic analyses that can be used to reconstruct cultural lineages. Evolutionary considerations also point to potential problems with current cross-country comparisons conducted within cultural psychology, such as the non-independence of data points due to shared cultural history. Finally, I argue that cultural psychology can play a central role in a synthetic evolutionary science of culture, providing valuable links between individual-oriented disciplines such as experimental psychology and neuroscience on the one hand, and society-oriented disciplines such as anthropology, history and sociology on the other, all within an evolutionary framework that provides links to the biological sciences.


2017 ◽  
Author(s):  
Alex Mesoudi

AbstractHow do migration and acculturation (i.e. psychological or behavioral change resulting from migration) affect within- and between-group cultural variation? Here I answer this question by drawing analogies between genetic and cultural evolution. Population genetic models show that migration rapidly breaks down between-group genetic structure. In cultural evolution, however, migrants or their descendants can acculturate to local behaviors via social learning processes such as conformity, potentially preventing migration from eliminating between-group cultural variation. An analysis of the empirical literature on migration suggests that acculturation is common, with second and subsequent migrant generations shifting, sometimes substantially, towards the cultural values of the adopted society. Yet there is little understanding of the individual-level dynamics that underlie these population-level shifts. To explore this formally, I present models quantifying the effect of migration and acculturation on between-group cultural variation, for both neutral and costly cooperative traits. In the models, between-group cultural variation, measured using F statistics, is eliminated by migration and maintained by conformist acculturation. The extent of acculturation is determined by the strength of conformist bias and the number of demonstrators from whom individuals learn. Acculturation is countered by assortation, the tendency for individuals to preferentially interact with culturally-similar others. Unlike neutral traits, cooperative traits can additionally be maintained by payoff-biased social learning, but only in the presence of strong sanctioning institutions. Overall, the models show that surprisingly little conformist acculturation is required to maintain realistic amounts of between-group cultural diversity. While these models provide insight into the potential dynamics of acculturation and migration in cultural evolution, they also highlight the need for more empirical research into the individual-level learning biases that underlie migrant acculturation.


2021 ◽  
Author(s):  
Alberto Acerbi

Cultural evolution can provide a useful framework to understand how information is produced, transmitted, and selected in contemporary online, digital, media. The diffusion of digital technologies triggered a radical departure from previous modalities of cultural transmission but, at the same time, general characteristics of human cultural evolution and cognition influence these developments. In this chapter, I will explore some areas where the links between cultural evolution research and digital media seem more promising. As cultural evolution-inspired research on internet phenomena is still in its infancy, these areas represent suggestions and links with works in other disciplines more than reviews of past research in cultural evolution. These include topics such as how to characterise the online effects of social influence and the spread of information; the possibility that digital, online, media could enhance cumulative culture; and the differences between online and offline cultural transmission. In the last section I will consider other possible future directions: the influences of different affordances in different media supporting cultural transmission; the role of producers of cultural traits; and, finally, some considerations on the effects on cultural dynamics of algorithms selecting information.


2021 ◽  
Author(s):  
Alberto Acerbi

Cultural evolution researchers use transmission chain experiments to investigate which content is more likely to survive when transmitted from one individual to another. These experiments resemble oral storytelling, where individuals need to understand, memorise, and reproduce the content. However, prominent contemporary forms of cultural transmission—think an online sharing— only involve the willingness to transmit the content. Here I present two fully preregistered online experiments that explicitly investigated the differences between these two modalities of transmission. The first experiment (N=1080) examined whether negative content, information eliciting disgust, and threat-related information were better transmitted than their neutral counterpart in a traditional transmission chain set-up. The second experiment (N=1200), used the same material, but participants were asked whether they would share or not the content in two conditions: in a large anonymous social network, or with their friends, in their favourite social network. Negative content was both better transmitted in transmission chain experiments and shared more than its neutral counterpart. Threat-related information was successful in transmission chain experiments but not when sharing, and, finally, information eliciting disgust was not advantaged in either. Overall, the results present a composite picture, suggesting that the interactions between the specific content and the medium of transmission are important and, possibly, that content biases are stronger when memorisation and reproduction are involved in the transmission—like in oral transmission—than when they are not—like in online sharing.


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