scholarly journals Inferring individual-level processes from population-level patterns in cultural evolution

2017 ◽  
Author(s):  
Anne Kandler ◽  
Bryan Wilder ◽  
Laura Fortunato
Keyword(s):  
Cultural Change ◽  
Cultural Evolution ◽  
Empirical Studies ◽  
Population Level ◽  
Theoretical Work ◽  
Cultural Variation ◽  
Group Level ◽  
Individual Level ◽  
The One ◽  
Over Time

AbstractOur species is characterized by a great degree of cultural variation, both within and between populations. Understanding how group-level patterns of culture emerge from individual-level behaviour is a long-standing question in the biological and social sciences. We develop a simulation model capturing demographic and cultural dynamics relevant to human cultural evolution, focusing on the interface between population-level patterns and individual-level processes. The model tracks the distribution of variants of cultural traits across individuals in a population over time, conditioned on different pathways for the transmission of information between individuals. From these data we obtain theoretical expectations for a range of statistics commonly used to capture population-level characteristics (e.g. the degree of cultural diversity). Consistent with previous theoretical work, our results show that the patterns observed at the level of groups are rooted in the interplay between the transmission pathways and the age structure of the population. We also explore whether, and under what conditions, the different pathways can be distinguished based on their group-level signatures, in an effort to establish theoretical limits to inference. Our results show that the temporal dynamic of cultural change over time retains a stronger signature than the cultural composition of the population at a specific point in time. Overall, the results suggest a shift in focus from identifying the one individual-level process that likely produced the observed data to excluding those that likely did not. We conclude by discussing the implications for empirical studies of human cultural evolution.

scholarly journals Inferring individual-level processes from population-level patterns in cultural evolution

2017 ◽  
Vol 4 (9) ◽  
pp. 170949 ◽  
Author(s):  
Anne Kandler ◽  
Bryan Wilder ◽  
Laura Fortunato
Keyword(s):  
Cultural Change ◽  
Cultural Evolution ◽  
Empirical Studies ◽  
Population Level ◽  
Theoretical Work ◽  
Cultural Variation ◽  
Group Level ◽  
Individual Level ◽  
The One ◽  
Over Time

Our species is characterized by a great degree of cultural variation, both within and between populations. Understanding how group-level patterns of culture emerge from individual-level behaviour is a long-standing question in the biological and social sciences. We develop a simulation model capturing demographic and cultural dynamics relevant to human cultural evolution, focusing on the interface between population-level patterns and individual-level processes. The model tracks the distribution of variants of cultural traits across individuals in a population over time, conditioned on different pathways for the transmission of information between individuals. From these data, we obtain theoretical expectations for a range of statistics commonly used to capture population-level characteristics (e.g. the degree of cultural diversity). Consistent with previous theoretical work, our results show that the patterns observed at the level of groups are rooted in the interplay between the transmission pathways and the age structure of the population. We also explore whether, and under what conditions, the different pathways can be distinguished based on their group-level signatures, in an effort to establish theoretical limits to inference. Our results show that the temporal dynamic of cultural change over time retains a stronger signature than the cultural composition of the population at a specific point in time. Overall, the results suggest a shift in focus from identifying the one individual-level process that likely produced the observed data to excluding those that likely did not. We conclude by discussing the implications for empirical studies of human cultural evolution.

scholarly journals Migration, acculturation, and the maintenance of between-group cultural variation

2017 ◽  
Author(s):  
Alex Mesoudi
Keyword(s):  
Social Learning ◽  
Cultural Values ◽  
Cultural Evolution ◽  
Population Level ◽  
Empirical Literature ◽  
Cultural Variation ◽  
Individual Level ◽  
And Migration ◽  
The Individual ◽  
Social Learning Processes

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.

Cultural Evolution

Anthropology ◽  
2012 ◽  
Author(s):  
Alex Mesoudi
Keyword(s):  
Evolutionary Theory ◽  
Cultural Change ◽  
Cultural Evolution ◽  
Biological Diversity ◽  
Cognitive Biases ◽  
Evolutionary Process ◽  
Population Level ◽  
Small Scale ◽  
Cultural Variation ◽  
Genetic Evolution

“Cultural evolution” is the idea that human cultural change––that is, changes in socially transmitted beliefs, knowledge, customs, skills, attitudes, languages, and so on––can be described as a Darwinian evolutionary process that is similar in key respects (but not identical) to biological/genetic evolution. More specifically, just as Darwin described biological/genetic evolution as comprising three key components––variation, competition (or selection), and inheritance––cultural change also comprises these same phenomena. Yet while cultural evolution can be described as Darwinian in this sense, the details of the processes (e.g., how variation is generated, or how information is transmitted) are likely to be different in the cultural case compared to the details of biological/genetic evolution. Bearing these differences in mind, cultural evolution researchers have taken many of the same methods, tools, and concepts that biologists have developed to explain biological diversity and complexity and used them to explain similar diversity and complexity in cultural systems. These include phylogenetic methods to reconstruct “macroevolutionary” historical relations between cultural traits (e.g., languages or tools), ethnographic field studies to document and explain contemporary cross-cultural variation, laboratory experiments to determine the small-scale details of cultural “microevolution” (e.g., how cognitive biases favor certain ideas over others or whether we preferentially learn from certain people within a group), and mathematical models to explore the long-term and population-level consequences of those microevolutionary processes. Given this interdisciplinary breadth, it has been suggested that evolutionary theory may serve as a synthetic framework for unifying the social sciences, just as evolutionary theory synthesized the biological sciences during the early 20th century.

scholarly journals Modelling cultural systems and selective filters

2020 ◽  
Author(s):  
Fredrik Jansson ◽  
Elliot Aguilar ◽  
Alberto Acerbi ◽  
Magnus Enquist
Keyword(s):  
Cultural Change ◽  
Cultural Evolution ◽  
Selection Process ◽  
Change Models ◽  
Individual Level ◽  
Modelling Framework ◽  
Structure Changes ◽  
Cultural Systems ◽  
Cultural Domain ◽  
The Individual

A specific goal of the field of cultural evolution is to understand how processes of transmission and selection at the individual level lead to population-wide patterns of cultural diversity and change. Models of cultural evolution have typically assumed that traits are independent of one another and essentially exchangeable. But culture has a structure: traits bear relationships to one another that affect the transmission and selection process itself. Here we introduce a modelling framework to explore the effect of cultural structure on the process of learning. Through simulations, we find that introducing this simple structure changes the cultural dynamics. Based on a basic filtering mechanism for parsing these relationships, more elaborate cultural filters emerge. In a mostly incompatible cultural domain of traits, these filters organise culture into mostly (but not fully) consistent and stable systems. Incompatible domains produce small homogeneous cultures, while more compatibility increases size, diversity, and group divergence. When individuals copy based on a trait's features (here, its compatibility relationships) they produce more homogeneous cultures than when they copy based on the agent carrying the cultural trait. We discuss the implications of considering cultural systems and filters in the dynamics of cultural change.

Paternal Relationships With Sons and Daughters

2021 ◽  
pp. 331-354
Author(s):  
Lambrianos Nikiforidis
Keyword(s):  
Empirical Studies ◽  
The Other ◽  
Same Sex ◽  
Financial Decisions ◽  
Traditional Family ◽  
Biological Sex ◽  
The Family ◽  
The One ◽  
Parental Bias ◽  
Over Time

This chapter examines paternal relationships with sons and daughters. Identity drives investment (and parental investment in particular), because people invest in that which aligns with their identity. And biological sex drives identity. These two ideas combined imply that a parent-offspring match in biological sex can influence parental favoritism in a systematic manner, an idea supported by recent empirical studies. This parental bias of concordant-sex favoritism can have broad implications, outside the context of the traditional family structure. In single parent or same-sex parent households, the consequences of this bias can be even stronger, because there would not be an opposite-direction bias from the other parent to even things out. This favoritism could have even broader ramifications, entirely outside the context of the family. On the one hand, whenever social norms dictate that men should control a family’s financial decisions, then sons may systematically receive more resources than daughters. This asymmetry in investment would then result in ever-increasing advantages that persist over time. On the other hand, if women are a family’s primary shoppers, this can manifest in subtle but chronic favoritism for daughters.

scholarly journals Cultural selection shapes network structure

2019 ◽  
Vol 5 (8) ◽  
pp. eaaw0609 ◽  
Author(s):  
Marco Smolla ◽  
Erol Akçay
Keyword(s):  
Social Networks ◽  
Network Structure ◽  
Cultural Evolution ◽  
Level Structure ◽  
Population Level ◽  
Trade Off ◽  
Skill Sets ◽  
Individual Level ◽  
Dense Networks ◽  
The Social

Cultural evolution relies on the social transmission of cultural traits along a population’s social network. Research indicates that network structure affects information spread and thus the capacity for cumulative culture. However, how network structure itself is driven by population-culture co-evolution remains largely unclear. We use a simple model to investigate how populations negotiate the trade-off between acquiring new skills and getting better at existing skills and how this trade-off shapes social networks. We find unexpected eco-evolutionary feedbacks from culture onto social networks and vice versa. We show that selecting for skill generalists results in sparse networks with diverse skill sets, whereas selecting for skill specialists results in dense networks and a population that specializes on the same few skills on which everyone is an expert. Our model advances our understanding of the complex feedbacks in cultural evolution and demonstrates how individual-level behavior can lead to the emergence of population-level structure.

Epigenetic and cultural evolution are non-Darwinian

2007 ◽  
Vol 30 (4) ◽  
pp. 371-371
Author(s):  
Liane Gabora
Keyword(s):  
Natural Selection ◽  
Cultural Evolution ◽  
Self Assembly ◽  
Population Level ◽  
Early Evolution ◽  
Epigenetic Change ◽  
Assembly Code ◽  
Individual Level ◽  
Evolution Of Life ◽  
Distinct Role

AbstractThe argument that heritable epigenetic change plays a distinct role in evolution would be strengthened through recognition that it is what bootstrapped the origin and early evolution of life, and that, like behavioral and symbolic change, it is non-Darwinian. The mathematics of natural selection, a population-level process, is limited to replication with negligible individual-level change that uses a self-assembly code.

scholarly journals Content bias in the cultural evolution of house finch song

2021 ◽  
Author(s):  
Mason Youngblood ◽  
David Lahti
Keyword(s):  
Cultural Evolution ◽  
Cultural Transmission ◽  
Population Level ◽  
R Package ◽  
House Finch ◽  
Population Declines ◽  
Individual Level ◽  
Transmission Mechanisms ◽  
Content Bias ◽  
Approximate Bayesian

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.

scholarly journals Different individual-level responses of great black-backed gulls (Larus marinus) to shifting local prey availability

2021 ◽  
Author(s):  
Laurie Maynard ◽  
Julia Gulka ◽  
Edward Jenkins ◽  
Gail K Davoren
Keyword(s):  
Prey Availability ◽  
Feeding Strategy ◽  
Population Level ◽  
Group Level ◽  
Generalist Species ◽  
Individual Level ◽  
Response Diversity ◽  
Capelin Mallotus Villosus ◽  
Larus Marinus ◽  
Generalist Diet

To grow, survive and reproduce under anthropogenic-induced changes, individuals must respond quickly and favourably to the surrounding environment. A species that feeds on a wide variety of prey types (i.e. generalist diet) may be comprised of generalist individuals, specialist individuals that feed on different prey types, or a combination of the two. If individuals within a population respond differently to an environmental change, population-level responses may not be detectable. By tracking foraging movements of eight great black-backed gulls ( Larus marinus ), a generalist species, we compared group-level and individual-level responses to an increase in prey biomass (capelin; Mallotus villosus ) during the breeding season in coastal Newfoundland, Canada. As hypothesized, shifts in prey availability resulted in significantly different individual responses in foraging behaviour and space use, which was not detectable when data from individuals were combined. Some individuals maintained similar foraging areas, foraging trip characteristics (e.g., trip length, duration) and habitat use with increased capelin availability, while others shifted foraging areas and habitats resulting in either increased or decreased trip characteristics. We show that individual specialization can be non-contextual in some gulls, whereby these individuals continuously use the same feeding strategy despite significant change in prey availability conditions. Findings also indicate high response diversity among individuals to shifting prey conditions that a population- or group-level study would not have detected, emphasizing the importance of examining individual-level strategies for future diet and foraging studies on generalist species.

scholarly journals Linked supergenes underlie split sex ratio and social organization in an ant

2021 ◽  
Author(s):  
German Lagunas-Robles ◽  
Jessica Purcell ◽  
Alan Brelsford
Keyword(s):  
Sex Ratio ◽  
Sex Allocation ◽  
Empirical Studies ◽  
Population Level ◽  
Theoretical Work ◽  
Female Offspring ◽  
Genomic Region ◽  
Genomic Conflict ◽  
Theoretical Predictions ◽  
Formica Podzolica

AbstractSexually reproducing organisms usually invest equally in male and female offspring. Deviations from this pattern have led researchers to new discoveries in the study of parent-offspring conflict, genomic conflict, and cooperation. Some social insect species exhibit the unusual population-level pattern of split sex ratio, wherein some colonies specialize in the production of future queens and others specialize in the production of males. Theoretical work focused on the relatedness asymmetries emerging from haplodiploid inheritance, whereby queens are equally related to daughters and sons, but their daughter workers are more closely related to sisters than to brothers, led to a series of testable predictions and spawned many empirical studies of this phenomenon. However, not all empirical systems follow predicted patterns, so questions remain about how split sex ratio emerges. Here, we sequence the genomes of 138 Formica glacialis workers from 34 male-producing and 34 gyne-producing colonies to determine whether split sex ratio is under genetic control. We identify a supergene spanning 5.5 Mbp that is closely associated with sex allocation in this system. Strikingly, this supergene is adjacent to another supergene spanning 5 Mbp that is associated with variation in colony queen number. We identify a similar pattern in a second related species, Formica podzolica. The discovery that split sex ratio is determined, at least in part, by a supergene in two species opens a new line of research on the evolutionary drivers of split sex ratio.Significance StatementSome social insects exhibit split sex ratio, wherein some colonies produce future queens and others produce males. This phenomenon spawned many influential theoretical studies and empirical tests, both of which have advanced our understanding of parent-offspring conflicts and cooperation. However, some empirical systems did not follow theoretical predictions, indicating that researchers lack a comprehensive understanding of the drivers of split sex ratio. Here, we show that split sex ratio is associated with a large genomic region in two ant species. The discovery of a genetic basis for sex allocation in ants provides a novel explanation for this phenomenon, particularly in systems where empirical observations deviate from theoretical predictions.

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