Welcome! I am Professor of Cultural Evolution in the Human Behaviour and Cultural Evolution Group at the University of Exeter’s Cornwall Campus, UK.
I study human cultural evolution. I am interested in how human culture evolved, and how culture itself evolves over time.
I use experiments to simulate cultural evolution in the lab. I get people to make and copy technological artifacts like arrowheads or handaxes, or solve problems resembling real-world challenges. The aim is to understand how psychological and social processes have shaped cultural change past and present.
I construct models of cultural evolution. These explore how individual decisions (e.g. when and from whom people learn) translate into population-level patterns of cultural change. I have modeled cumulative technological change, copycat suicides, and the effects of migration on cultural diversity.
I analyse big datasets to explain real world patterns of cultural evolution. Recent analyses have explored the cultural evolution of pop music and football tactics.
The human species has an extraordinary reliance on culture, i.e. the vast body of beliefs, knowledge and skills that we acquire from other individuals via social learning. While other species adapt to their environments primarily via genetic evolution, we adapt via cultural evolution. I am interested in how this process of cultural evolution works, its similarities and differences to genetic evolution, and how traditional social science findings and topics can be studied within an evolutionary framework.
Learning from others, aka 'social learning', lies at the heart of human culture. I have run several lab experiments examining how people learn from one another, who they learn from, when they learn from others rather than alone, and what they learn. Some studies use the 'transmission chain method', where stories or task solutions are passed along linear chains of participants like the game 'Telephone'. These have found, for example, that information about social relationships and interactions is transmitted better than non-social information. Other studies look at how people within fixed groups learn from one another over time. Often these experiments look at technological change, getting participants to design arrowheads, handaxes or other objects reflecting real-life human technology. Previous findings have shown that people prefer to learn from successful others, but often copy others less than they should do; and that causal understanding is often not necessary for improvements in technologies.
I have used theoretical models, primarily agent-based simulations, to explore how different learning dynamics - who copies what, from whom and when - might generate large-scale patterns of cultural evolution. Previous models have looked at beliefs in partible paternity (where children have more than one biological 'father'), copycat suicide, and how the costs of acquiring ever-accumulating knowledge slows down innovation in cumulative cultural evolution.
Ever since our species dispersed out of Africa, migration has been a constant fixture of Homo sapiens. 'Acculturation' describes the psychological and behavioural changes that occur as a result of migration. I have recently studied how acculturation affects the psychological characteristics of first and second generation British Bangladeshi migrants in London, as well as theoretical models of how acculturation and migration interact to shape cultural diversity over time. Lab experiments have mapped cross-cultural variation in social learning, showing higher rates of social learning in mainland China than in the West.
Mesoudi, Chang, Murray and Lu (2015) Higher frequency of social learning in China than in the West shows cultural variation in the dynamics of cultural evolution. Proceedings of the Royal Society B 282, 20142209.
People often preferentialy learn from high-status, respected and knowledgeable individuals within their societies. This tendency is known as 'prestige-biased' social learning. A series of recent lab, field and online experiments have tested the extent to which people form prestige hierarchies in naturally-occurring human groups, and when people employ prestige-biased social learning.
The digital age has yielded big cultural datasets that can be used to quantitatively analyse patterns of real-life cultural evolution. Two recent projects have analysed how large-scale, long-term changes in pop music lyrics and in football tactics can be explained in terms of underlying social learning biases.
In order to adaptively solve complex problems or make difficult decisions, people must strategically combine personal information acquired directly from experience (individual learning) and social information acquired from others (social learning). The game of football (soccer) provides extensive real world data with which to quantify this strategic information use. I analyse a 5-year dataset of all games (n = 9127, 2012-2017) in five top European leagues to quantify the extent to which a manager’s initial formation is guided by their personal past use or success with that formation, or other managers’ use or success with that formation. I focus on the 4231 formation, the dominant formation during this period. As predicted, a manager’s choice of whether to use 4231 is influenced by both their recent use of 4231 (personal information) and the use of 4231 in the entire population of managers in that division (social information). Against expectations, managers relied more on personal than social information, although this estimate was highly variable across managers and divisions. Finally, there did not appear to be an adaptive tradeoff between social and personal information use, with the relative reliance on each failing to predict managerial success.
Our species has the peculiar ability to accumulate cultural innovations over multiple generations, a phenomenon termed `cumulative cultural evolution’ (CCE). Recent years have seen a proliferation of empirical and theoretical work exploring the interplay between demography and CCE. This has generated intense discussion about whether demographic models can help explain historical patterns of cultural changes. Here, we synthesize empirical and theoretical studies from multiple fields to highlight how both population size and structure can shape the pool of cultural information that individuals can build upon to innovate, present the potential pathways through which humans’ unique social structure might promote CCE, and discuss whether humans’ social networks might partly result from selection pressures linked to our extensive reliance on culturally accumulated knowledge.
Prestige-biased social learning occurs when individuals preferentially learn from others who are highly respected, admired, copied, or attended to in their group. This form of social learning is argued to reflect novel forms of social hierarchy in human societies, and, by providing an efficient short-cut to acquiring adaptive information, underpin the cumulative cultural evolution that has contributed to our species’ ecological success. Despite these potentially important consequences, little empirical work to date has tested the basic predictions of prestige-biased social learning. Here we provide evidence supporting the key predictions that prestige-biased social learning is used when it constitutes an indirect cue of success, and when success-biased social learning is unavailable. We ran an online experiment (n=269) in which participants could copy each other in real-time to score points on a general-knowledge quiz. Our implementation of prestige was the number of times someone had previously been copied by others. Importantly, prestige was an emergent property of participants’ behaviour during the experiment; no deception or manipulation of prestige was employed at any time. We found that, as predicted, participants used prestige-biased social learning when the prestige cue was an indirect cue of success, and when direct success information was unavailable. This highlights how people flexibly and adaptively employ social learning strategies based on the reliability of the information that such strategies provide.
Bows and arrows, houses and kayaks are just a few examples of the highly optimized tools that humans have produced and used to colonize new environments. Because there is much evidence that humans’ cognitive abilities are unparalleled, many believe that such technologies resulted from our superior causal reasoning abilities. However, others have stressed that the high dimensionality of human technologies makes them very difficult to understand causally. Instead, they argue that optimized technologies emerge through the retention of small improvements across generations without requiring understanding of how these technologies work. Here we show that a physical artefact becomes progressively optimized across generations of social learners in the absence of explicit causal understanding. Moreover, we find that the transmission of causal models across generations has no noticeable effect on the pace of cultural evolution. The reason is that participants do not spontaneously create multidimensional causal theories but, instead, mainly produce simplistic models related to a salient dimension. Finally, we show that the transmission of these inaccurate theories constrains learners’ exploration and has downstream effects on their understanding. These results indicate that complex technologies need not result from enhanced causal reasoning but, instead, can emerge from the accumulation of improvements made across generations.
Prestige and dominance are thought to be two evolutionarily distinct routes to gaining status and influence in human social hierarchies. Prestige is attained by having specialist knowledge or skills that others wish to learn, whereas dominant individuals use threat or fear to gain influence over others. Previous studies with groups of unacquainted students have found prestige and dominance to be two independent avenues of gaining influence within groups. We tested whether this result extends to naturally occurring social groups. We ran an experiment with 30 groups of people from Cornwall, UK (n = 150). Participants answered general knowledge questions individually and as a group, and subsequently nominated a representative to answer bonus questions on behalf of the team. Participants then anonymously rated all other team-mates on scales of prestige, dominance, likeability and influence on the task. Using a model comparison approach with Bayesian multi-level models, we found that prestige and dominance ratings were predicted by influence ratings on the task, replicating previous studies. However, prestige and dominance ratings did not predict who was nominated as team representative. Instead, participants nominated team members with the highest individual quiz scores, despite this information being unavailable to them. Interestingly, team members who were initially rated as being high status in the group, such as a team captain or group administrator, had higher ratings of both dominance and prestige than other group members. In contrast, those who were initially rated as someone from whom others would like to learn had higher prestige, but not higher dominance, supporting the claim that prestige reflects social learning opportunities. Our results suggest that prestige and dominance hierarchies do exist in naturally occurring social groups, but that these hierarchies may be more domain-specific and less flexible than we anticipated.
How do migration and acculturation (i.e. psychological or behavioral change resulting from migration) affect within- and between-group cultural variation? Here I address 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 mechanisms (e.g. 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.
Prospective postdocs and PhD students are welcome to email me at firstname.lastname@example.org to explore projects and funding.
This tutorial shows how to create very simple simulation or agent-based models of cultural evolution in R. It uses the RStudio notebook or RMarkdown (.Rmd) format, allowing you to execute code as you read the explanatory text. Each model is contained in a separate RMarkdown file which you should open in RStudio. Currently these are:
The tutorial is freely available at https://github.com/amesoudi/cultural_evolution_ABM_tutorial
BBC Radio 4: The Human ZooContributor, Series 8 Episode 4: Democracy and the Wisdom of the Crowds
Al Jazeera America: Do different generations of immigrants think differently?Feature/interview on the cross-cultural thinking styles project by novelist Ned Beauman
The Forum Debate: Darwinism and the Social SciencesPanellist. Organised by the Forum for European Philosophy, London School of Economics
Presentation at the National Academy of Sciences Arthur M. Sackler Colloquium on the Extension of Biology Through Culture held at the Beckman Center in Irvine, CA on November 15-16, 2016, organized by Marcus Feldman, Francisco J. Ayala, Andrew Whiten and Kevin Laland.
Towards A Science Of Culture Within A Darwinian Evolutionary Framework. Moderator: Prof. Itamar Even-Zohar. Tel-Aviv, Israel. 2nd June 2015