publications by categories in reversed chronological order. generated by jekyll-scholar.
- Pathways to Cultural Adaptation: The Coevolution of Cumulative Culture and Social NetworksMarco Smolla, and Erol AkçayFeb 2023
Humans have adapted to an immense array of ecologies by accumulating culturally transmitted knowledge and skills. Culture accumulates in at least two ways: via more distinct cultural traits, or via improvements of existing cultural trait. A trade-off is expected between these owing to the fact that social learning opportunities are finite and social learning often requires multiple exposures. Furthermore, what kind of culture accumulates depends on, and coevolves with, the social structure of societies. Here we show that the coevolution of social networks for learning and cumulative culture results in two distinct pathways to cultural adaptation: highly connected populations with high proficiency but low cultural trait diversity vs. sparsely connected populations with low proficiency but more cultural trait diversity. Importantly, we show there is a general conflict between group-level payoffs, which is maximised in highly connected groups that attain high proficiency, and individual level selection, which favours disconnection. This conflict emerges from the interaction of social learning with population structure and causes populations to cycle between the two cultural and network states. The same conflict creates a paradox where improving individual innovation rates lowers the payoffs of groups. Finally, we explore how populations navigate these two pathways in heterogeneous and changing environments, and show that high heterogeneity in payoffs and slow rate of environmental change favours high proficiency, while fast rate of environmental change favours more trait diversity. We also find that the proficiency pathway to cultural adaptation is favoured with increased population size, but only in slow changing environments. Our results uncover previously unrecognised trade-offs and tensions in the coevolutionary dynamics of cumulative culture and social structure, with broad implications for human social evolution.
- RoutledgeIndividual-Based Models of Cultural Evolution: A Step-by-Step Guide Using RAlberto Acerbi, Alex Mesoudi, and Marco SmollaFeb 2022
"Individual-Based Models of Cultural Evolution shows readers how to create individual-based models of cultural evolution using the programming language R. The field of cultural evolution has emerged in the last few decades as a thriving, interdisciplinary effort to understand cultural change and cultural diversity within an evolutionary framework and using evolutionary tools, concepts and methods"–
- Reciprocity Supports Cooperation in Real-World Economic InteractionsTaylor Z. Lange, Marco Smolla, and Timothy WaringMay 2022
Evolutionary scientists argue that cooperation is central to human ecological success. Theoretical models, and behavioral experiments have found that human cooperation is conditional and context dependent, that individuals vary in their propensity to cooperate, and that cooperation can be stabilized by reciprocity within a group. However, outside of behavioral experiments, these findings have been difficult to validate with observations of cooperation in natural settings, especially in industrial societies, cash economies and structured organizational contexts. Here, we report in situ observations of behavioral cooperation and reciprocity from organizations embedded in a cash economy. We study small consumer food cooperatives or ‘food clubs’, in which members share bulk food purchases, and are considered to be heavily dependent on cooperation. We take advantage of a high-resolution purchasing dataset of all economic interactions for 1,528 individuals across 35 clubs, including 10,261 bulk purchases over a combined total of 107 years of club purchasing data. We develop a network method to detect economic reciprocity, categorize economic behavior as directly reciprocal, indirectly reciprocal, or non-reciprocal, and statistically classify individual behavioral types (reciprocator, helper, and beneficiary). Observed patterns of reciprocity confirm the central findings of theoretical and experimental studies. Reciprocity is highly abundant in most clubs, with direct reciprocity far more common (72%) than indirect reciprocity (11%). Reciprocators are the most common (69%) and the most stable behavioral type, but clubs vary significantly. Our results provide some of the first observational evidence of economic reciprocity and cooperation generally. They imply that cooperation may be a more important force in industrial societies, organizational contexts, and cash economies than currently understood. These results solidify the findings of the behavioral study of cooperation and open the door for greater study and application of cooperation in organizational management and economic policy.
- What Makes Inventions Become Traditions?Susan E. Perry, Alecia Carter, Jacob G. Foster, Sabine Nöbel, and Marco SmollaAnnual Review of Anthropology, Oct 2022
Although anthropology was the first academic discipline to investigate cultural change, many other disciplines have made noteworthy contributions to understanding what influences the adoption of new behaviors. Drawing on a broad, interdisciplinary literature covering both humans and nonhumans, we examine ( a) which features of behavioral traits make them more transmissible, ( b) which individual characteristics of inventors promote copying of their inventions, ( c) which characteristics of individuals make them more prone to adopting new behaviors, ( d) which characteristics of dyadic relationships promote cultural transmission, ( e) which properties of groups (e.g., network structures) promote transmission of traits, and ( f) which characteristics of groups promote retention, rather than extinction, of cultural traits. One of anthropology’s strengths is its readiness to adopt and improve theories and methods from other disciplines, integrating them into a more holistic approach; hence, we identify approaches that might be particularly useful to biological and cultural anthropologists, and knowledge gaps that should be filled.
- Not by Transmission Alone: The Role of Invention in Cultural EvolutionSusan Perry, Alecia Carter, Marco Smolla, Erol Akçay, Sabine Nöbel, Jacob G. Foster, and Susan D. HealyPhilosophical Transactions of the Royal Society B: Biological Sciences, Jul 2021
Innovation—the combination of invention and social learning—can empower species to invade new niches via cultural adaptation. Social learning has typically been regarded as the fundamental driver for the emergence of traditions and thus culture. Consequently, invention has been relatively understudied outside the human lineage—despite being the source of new traditions. This neglect leaves basic questions unanswered: what factors promote the creation of new ideas and practices? What affects their spread or loss? We critically review the existing literature, focusing on four levels of investigation: traits (what sorts of behaviours are easiest to invent?), individuals (what factors make some individuals more likely to be inventors?), ecological contexts (what aspects of the environment make invention or transmission more likely?), and populations (what features of relationships and societies promote the rise and spread of new inventions?). We aim to inspire new research by highlighting theoretical and empirical gaps in the study of innovation, focusing primarily on inventions in non-humans. Understanding the role of invention and innovation in the history of life requires a well-developed theoretical framework (which embraces cognitive processes) and a taxonomically broad, cross-species dataset that explicitly investigates inventions and their transmission. We outline such an agenda here. This article is part of the theme issue ‘Foundations of cultural evolution’.
- Underappreciated Features of Cultural EvolutionMarco Smolla, Fredrik Jansson, Laurent Lehmann, Wybo Houkes, Franz J. Weissing, Peter Hammerstein, Sasha R. X. Dall, Bram Kuijper, and Magnus EnquistPhilosophical Transactions of the Royal Society B: Biological Sciences, Jul 2021
Cultural evolution theory has long been inspired by evolutionary biology. Conceptual analogies between biological and cultural evolution have led to the adoption of a range of formal theoretical approaches from population dynamics and genetics. However, this has resulted in a research programme with a strong focus on cultural transmission. Here, we contrast biological with cultural evolution, and highlight aspects of cultural evolution that have not received sufficient attention previously. We outline possible implications for evolutionary dynamics and argue that not taking them into account will limit our understanding of cultural systems. We propose 12 key questions for future research, among which are calls to improve our understanding of the combinatorial properties of cultural innovation, and the role of development and life history in cultural dynamics. Finally, we discuss how this vibrant research field can make progress by embracing its multidisciplinary nature. This article is part of the theme issue ‘Foundations of cultural evolution’.
- Competition for Resources Can Promote the Divergence of Social Learning PhenotypesR. Tucker Gilman, Fern Johnson, and Marco SmollaProceedings of the Royal Society B: Biological Sciences, Feb 2020
Social learning occurs when animals acquire knowledge or skills by observing or interacting with others and is the fundamental building block of culture. Within populations, some individuals use social learning more frequently than others, but why social learning phenotypes differ among individuals is poorly understood. We modelled the evolution of social learning frequency in a system where foragers compete for resources, and there are many different foraging options to learn about. Social learning phenotypes diverged when some options offered much better rewards than others and expected rewards changed moderately quickly over time. When options offered similar rewards or when rewards changed slowly, a single social learning phenotype evolved. This held for fixed and simple conditional social learning rules. Sufficiently complex conditional social learning rules prevented the divergence of social learning phenotypes under all conditions. Our results explain how competition can promote the divergence of social learning phenotypes.
- Evolution of Contribution Timing in Public Goods GamesBryce Morsky, Marco Smolla, and Erol AkçayProceedings of the Royal Society B: Biological Sciences, May 2020
Life-history strategies are a crucial aspect of life, which are complicated in group-living species, where pay-offs additionally depend on others’ behaviours. Previous theoretical models of public goods games have generally focused on the amounts individuals contribute to the public good. Yet a much less-studied strategic aspect of public goods games, the timing of contributions, can also have dramatic consequences for individual and collective performance. Here, we develop two stage game theoretical models to explore how the timing of contributions evolves. In the first stage, individuals contribute to a threshold public good based on a performance schedule. The second stage begins once the threshold is met, and the individuals then compete as a function of their performance. We show how contributing rapidly is not necessarily optimal, because delayers can act as ‘cheats,’ avoiding contributing while reaping the benefits of the public good. However, delaying too long can put the delayers at a disadvantage as they may be ill-equipped to compete. These effects lead to bistability in a single group, and spatial diversity among multiple interacting groups.
- Capuchin Monkey Rituals: An Interdisciplinary Study of Form and FunctionSusan Perry, and Marco SmollaPhilosophical Transactions of the Royal Society B: Biological Sciences, Aug 2020
Many white-faced capuchin monkey dyads in Lomas Barbudal, Costa Rica, practise idiosyncratic interaction sequences that are not part of the species-typical behavioural repertoire. These interactions often include uncomfortable or risky elements. These interactions exhibit the following characteristics commonly featured in definitions of rituals in humans: (i) they involve an unusual intensity of focus on the partner, (ii) the behaviours have no immediate utilitarian purpose, (iii) they sometimes involve ‘sacred objects’, (iv) the distribution of these behaviours suggests that they are invented and spread via social learning, and (v) many behaviours in these rituals are repurposed from other behavioural domains (e.g. extractive foraging). However, in contrast with some definitions of ritual, capuchin rituals are not overly rigid in their form, nor do the sequences have specific opening and closing actions. In our 9260 h of observation, ritual performance rate was uncorrelated with amount of time dyads spent in proximity but (modestly) associated with higher relationship quality and rate of coalition formation across dyads. Our results suggest that capuchin rituals serve a bond-testing rather than a bond-strengthening function. Ritual interactions are exclusively dyadic, and between-dyad consistency in form is low, casting doubt on the alternative hypothesis that they enhance group-wide solidarity. This article is part of the theme issue ‘Ritual renaissance: new insights into the most human of behaviours’.
- SciAdvCultural Selection Shapes Network StructureMarco Smolla, and Erol AkçayScience Advances, Aug 2019
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.
- Reproductive Skew Affects Social Information UseMarco Smolla, Charlotte Rosher, R. Tucker Gilman, and Susanne ShultzRoyal Society Open Science, Jul 2019
Individuals vary in their propensity to use social learning, the engine of cultural evolution, to acquire information about their environment. The causes of those differences, however, remain largely unclear. Using an agent-based model, we tested the hypothesis that as a result of reproductive skew differences in energetic requirements for reproduction affect the value of social information. We found that social learning is associated with lower variance in yield and is more likely to evolve in risk- averse low-skew populations than in high-skew populations. Reproductive skew may also result in sex differences in social information use, as empirical data suggest that females are often more risk-averse than males. To explore how risk may affect sex differences in learning strategies, we simulated learning in sexually reproducing populations where one sex experiences more reproductive skew than the other. When both sexes compete for the same resources, they tend to adopt extreme strategies: the sex with greater reproductive skew approaches pure individual learning and the other approaches pure social learning. These results provide insight into the conditions that promote individual and species level variation in social learning and so may affect cultural evolution.
- Second Annual Workshop of the Association of Early-Career Social Learning Researchers in St Andrews, ScotlandMarco Smolla, Edith Invernizzi, Marina Bazhydai, Marco Casoli, Dominik Deffner, Gonçalo S. Faria, Nicholas Jones, Jasmeen Kanwal, Anna-Margarete Staehler, and Ryutaro UchiyamaEvolutionary Anthropology: Issues, News, and Reviews, Jul 2018
- Meth Eco EvolSimilarity in Spatial Utilization Distributions Measured by the Earth Mover’s DistanceBart Kranstauber, Marco Smolla, and Kamran SafiMethods in Ecology and Evolution, Jul 2016
Estimating the similarity in space use (spatio-temporal home range overlap) of animals is important formany questions regarding behavioural ecology, wildlife management and conservation. The current methods that calculate joint space use generally do not account for proximity in space use, as all of them rely on the differences between the exact spatial overlay of utilization distributions, while spatial distances between distributions should be considered to truly quantify similarity.
- Copy-When-Uncertain: Bumblebees Rely on Social Information When Rewards Are Highly VariableMarco Smolla, Sylvain Alem, Lars Chittka, and Susanne ShultzBiology Letters, Jul 2016
To understand the relative benefits of social and personal information use in foraging decisions, we developed an agent-based model of social learning that predicts social information should be more adaptive where resources are highly variable and personal information where resources vary little. We tested our predictions with bumblebees and found that foragers relied more on social information when resources were variable than when they were not. We then investigated whether socially salient cues are used prefer- entially over non-social ones in variable environments. Although bees clearly used social cues in highly variable environments, under the same conditions they did not use non-social cues. These results suggest that bumblebees use a ‘copy-when-uncertain’ strategy.
- Competition for Resources Can Explain Patterns of Social and Individual Learning in NatureMarco Smolla, R Tucker Gilman, Tobias Galla, and Susanne ShultzProceedings of the Royal Society B: Biological Sciences, Jul 2015
In nature, animals often ignore socially available information despite the multiple theoretical benefits of social learning over individual trial-and-error learning. Using information filtered by others is quicker, more efficient and less risky than randomly sampling the environment. To explain the mix of social and individual learning used by animals in nature, most models penalize the quality of socially derived information as either out of date, of poor fidelity or costly to acquire. Competition for limited resources, a fundamental evolutionary force, provides a compelling, yet hitherto overlooked, explanation for the evolution of mixed-learning strategies. We present a novel model of social learning that incorporates competition and demonstrates that (i) social learning is favoured when competition is weak, but (ii) if competition is strong social learning is favoured only when resource quality is highly variable and there is low environmental turnover. The frequency of social learning in our model always evolves until it reduces the mean foraging success of the population. The results of our model are consistent with empirical studies showing that individuals rely less on social information where resources vary little in quality and where there is high within-patch competition. Our model provides a framework for understanding the evolution of social learning, a prerequisite for human cumulative culture.