Denmark

**Author(s):** Campenni, M.; Takahashi, T.; Wada, M.&lt;br&gt;&lt;br&gt;Many human populations on the globe have the law system, obliging individuals to conform to a certain norm, violation of which is usually followed by the punishment from the third-party. Using a model of group competition among distinct subpopulations, we will simulate the co-evolution of the law internalized in a population and the cooperative behavior through prisoner’s dilemma (PD) game with third-party punishment. Unlike the standard PD game, third-party punishment in our model takes place only if the subpopulation in question has the internalized law system. Our model also includes the competition among subpopulations, in which those with higher payoff tend to win. We show that whereas the law and cooperative behavior may evolve for certain parameter sets concerning the payoffs of the PD game, the population will lose the law and be occupied by defectors in majority of the cases.

Cultural Evolution Society 2022

Co-evolution of cooperative behavior, third-party punishment, and law: Simulation study based on prisoner’s dilemma game

**Author(s):** Campenni, M.; Takahashi, T.; Wada, M. Many human populations on the globe have the law system, obliging individuals to conform to a certain norm, violation of which is usually followed by the punishment from the third-party. Using a model of group competition among distinct subpopulations, we will simulate the co-evolution of the law internalized in a population and the cooperative behavior through prisoner’s dilemma (PD) game with third-party punishment. Unlike the standard PD game, third-party punishment in our model takes place only if the subpopulation in question has the internalized law system. Our model also includes the competition among subpopulations, in which those with higher payoff tend to win. We show that whereas the law and cooperative behavior may evolve for certain parameter sets concerning the payoffs of the PD game, the population will lose the law and be occupied by defectors in majority of the cases.

technical paper

### Welcome to the fourth Cultural Evolution Society Conference, CES2022! 

As last year, Underline will support the online component of the conference. The ongoing COVID-19 pandemic is causing a great deal of uncertainty for all of us. Therefore, we seek to offer a hybrid format that will hopefully allow some folks to travel to Aarhus, others to meet up locally or regionally in CES hub-lets, and other yet to participate online. The field of cultural evolution is growing in size and scope; its theories, methods and applications - both academic and applied - are getting ever more robust. Do join us in what promises to be an exciting exchange of ideas and a celebration of our field.

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#### The CES 2022 local organising committee
* Luseadra Joy McKerracher
* Jesper Sørensen 
* Niels Nørkjær Johannsen 
* Benjamin Grant Purzycki 
* Mette Løvschal 
* Felix Riede
* Iza Romanowska 
* Karsten Olsen

Please click on the button bellow if you want to watch the videos

The field of cultural evolution is growing in size and scope; its theories, methods and applications - both academic and applied - are getting ever more robust. Do join us in what promises to be an exciting exchange of ideas and a celebration of our field.

**Author(s):** Heckelsmiller, C; Lightner, A. D; Quinlan, M. B. People use folk scientific concepts in ethnomedicine when confronting diseases in humans, other animals, and plants, especially when those organisms are part of a human food system. Yet, little is known about how explanatory models (EMs) of animal and plant diseases adapt when subsistence systems change. Traditionally pastoralists, many Maasai communities in East Africa have intensified agricultural production and interactions with Western scientific paradigms. Using participant observation and interviews with 95 members of a Tanzanian Maasai community, we investigate how participants explain illness events for humans, animals, and plants. We found that people often adopt Western scientific interventions, but keep traditional medical explanations which vary between plant and animal cases. Our findings suggest that EM content for plant and animal disease appears to be differentially constrained by 1) cognitive construals (e.g. a tendency for essentialism, anthropocentrism, teleology); 2) biological coherence; 3) barriers/ attractors to intervention access. We discuss how these factors are important in understanding how folk science evolves and may influence development initiatives.

Ethnomedicine for People, Animals, and Plants; Evolving Explanatory Models in a Changing Subsistence System

**Author(s):** Albuquerque, R; Codogno, B; dos Santos, B; Izar, P In primates, touching is fundamental for the social development of infants. We hypothesized that the frequency of touching the face of other individuals by Sapajus libidinosus infants, assuming an active role within their social network, is correlated to the number of social interactions they establish. We analyzed 41 hours of videos of a wild capuchin group at Piauí, Brazil, recorded using focal animal sampling, from the digital data collection from the Laboratory of Ethology, Development and Social Interactions, corresponding to the 1st, 2nd and 3rd months of life of 6 infants (3 males and 3 females). All social interactions and facial touches involving the infant under analysis were coded. A total of 485 interactions and 45 touches were registered. We conducted a GLMM, considering individual and month as fixed effects and sex as a random variable. We found no correlation between the number of interactions of the infant and the number of touches on the face of other individuals. Future studies should investigate other factors, such as infant temperament, that might explain variation in frequency of touching.

Is the touch of capuchin monkeys infants (Sapajus libidinosus) on other individuals influenced by their popularity?

**Author(s):** Delval, I; Fernández-Bolaños, M; Visalberghi, E; Izar, P; Valentova, JV Among nonhuman primates (NHP), same-sex sexual behavior (SSB) is frequent and appears in several forms, such as courtship, mounting or manual-genital-oral stimulation. Possible functions include practice for heterosexual copulation, tension regulation, reconciliation or bond strengthening. Sexual interactions, though, varies among populations and species. Dual-inheritance perspective can be taken to explore possible interactions between evolved same-sex attractions and specific behaviors that are modified by social learning, occur under specific conditions, and can serve for novel social functions. Capuchin monkeys are known for their rich sexual behavior, with elaborated courtships. While same-sex mounting and genital inspection are common in capuchins’ play, same-sex courtship has been overlooked. Here we describe the first case of two young (one weaning infant and one sub-adult) males of wild-living Sapajus xanthosternos, performing a 15-min courtship. The males performed 16 out of 20 previously described heterosexual behaviors, showing a great overlap with adult courtship. If “practice hypothesis” is correct, this behavior should be widespread among males and females throughout development. Instead, we propose that sex (homosexual and heterosexual) is a powerful and efficient way of communicating social messages, so here it has “strengthening bonds” function. This could extend the prosocial hypothesis for same-sex attraction in humans to NHP.

SOCIALLY MODIFIED MEANING OF SEX: A CASE OF HOMOSEXUAL COURTSHIP IN CAPUCHIN MONKEYS

**Author(s):** Ottoni, E; Coutinho, P; Falótico, T We surveyed tool use by 3 groups of capuchin monkeys in S. das Confusões Nat. Park (Brazil), a savannah population equidistant from two long-term study sites - Faz. Boa Vista, where monkeys are expert nutcrackers, but do not use digging stones nor probes, and S. da Capivara, where all 3 are customary. We employed direct observation, camera traps, indirect observation of tool use sites, and two experiments, one on induced seeds' excavation, the other on probe use, based in a previous comparative study (FBV x PNSC). Nutcracking was observed as expected, but no probing. Stone-aided digging of arthropods and tubers was indirectly registered in the range of one group; one of the other groups (the only one to take part) did not use tools in the digging experiment. In the molasses-probing task, monkeys did not succeed, except by one innovator, but made inept attempts to hit the box with sticks or stones. The results on stone-aided digging are not conclusive but suggest resource-availability causes. The apparent absence of customary probe use, with no clear environmental causes, seems to point to a lower probability of the establishment of a tradition with less cultural niche construction.

Comparing the toolkits of three savannah populations of bearded capuchin monkeys (Sapajus libidinosus): environmental and traditional factors.

Humans use a wide variety of representational patterns to express numbers. Some of these representations also straddle different modalities, and sign languages (SLs) are a prime example: Their users produce and receive signals in visuospatial space but adopt tools and strategies linked to the oral/auditory modality; and in SLs numerals resemble notational systems. At the same time, systems may possess rare features that are neither attested in SLs used by neighboring communities nor related to the surrounding spoken languages. Such features include, for instance, how compound numbers are structured or whether number representation is quantitative or symbolic, and whether the form involves hand movements or repetitions. Because of this variety in structure and form, numerals in SLs challenge cross-modality feature analysis. In this talk, I will show how a distributed cognition approach can be made fruitful for their analysis. This approach recognizes that numerical cognition operates on information that is distributed across internal and external representations, and that the way in which numbers are externally represented shapes cognitive behaviors (representational effects).


A distributed approach to numerals in sign languages

In groups of the Evangelical tradition, public conversion testimonies are essential when considering a neophyte for membership. Interestingly, in these groups, every member must undergo conversion experience and display their converted nature – actual converts and those brought up in the tradition. In their public conversion testimonies, members signal their loyalty to the group and try to convince others about their commitment and trustworthiness. Contrary to the group's theology that both groups of neophytes are equal, my previous study found significant differences in public conversion testimonies between the individuals who have been part of the group since childhood and strangers in the effort to persuade others operationalized as the length of testimony and amount of negative self-depiction. Except for this difference in public conversion testimonies, their function remains unknown, and we are at the beginning of its understanding. Based on these findings, I'd like to present a research design to study changes in commitment for both groups and if high-conversion performers are treated more for their commitment than low-conversion performers.

Public conversion testimonies and group commitment

We investigate how aggression towards enemy out-group spreads among in-groups during intergroup conflicts. Focusing on the role of learning biases, we tested whether prestige and credibility enhancing displays of in-group leaders motivate other in-groups to participate in intergroup aggression. Using a minimal group paradigm and an intergroup prisoner’s dilemma with maximized differences on a Czech sample, our results show that the transmission of intergroup aggression is promoted by credibility enhancing displays and by the prestige of group leaders, not their dominance. Furthermore, taking advantage of the naturally occurring event, the storming of the US Capitol, we studied whether group affiliation influences how Americans perceive the aggressive behavior of the shooting officer and shot A. E. Babbitt. Our findings suggest that the group affiliation and the support for the storming predict perceived prestige and dominance diversely for both actors. We conclude that given the context of an intergroup conflict, leaders can increase participation in aggressive behaviors towards out-groups by prestigious motivation, sidestepping the coercive pathway of dominance.

Effect of prestige and CREDs on intergroup aggression

Groups mediate the transmission of culture and are often the center of cooperative activities. They are also dynamic, contingent on socio-environmental conditions. Here I introduce a statistical and ethnographic data collection framework for mapping the relationships between group identities, anticipating complementary work that will reveal the driving forces behind group topologies.

Group topology

Across many countries, the Russian invasion of Ukraine prompted individuals to help anonymous and more or less distant Ukrainians fleeing or defending their country. Utilizing this crisis as a natural experiment, we tested evolutionary mechanisms hypothetically responsible for this surge of extra-group prosociality, focusing on kin-based, kith-based, and indirect reciprocity, and moralizing gods beliefs. On a sample of 3051 participants from 16 countries recruited in an online survey, we measured relatedness coefficients, reciprocal relations with Ukrainian friends, cultural and geographical distance from Ukraine, and moralizing gods beliefs to test their effects on three forms of extra-group prosociality: monetary donations, volunteering, and attending pro-Ukraine happenings. While attending happenings is predicted by kin and kith ties, volunteering is also predicted by the belief in a moralizing god. Data on monetary donations are still being cleaned and are yet to be modeled. For now, we argue that the differences in the effects of the studied predictors rely to the costliness of the forms of extra-group prosociality and the sampled populations’ distance from Ukraine.

Helping Ukraine: Mechanisms promoting extra-group prosociality towards the Ukrainians during the 2022 invasion

Human culture, despite its immense complexity, is often reduced to fit into a particular framework when studied quantitatively. We know, thanks to the number of studies to date, that people select among the available variants while modifying them during transmission. We also know that different biases play a role in this process. We set out to combine existing approaches into a single mathematical model and determine the extent to which they affect cultural transmission. Our main objective is to estimate parameter values in a continuous cultural inheritance model that considers the proportionality in variance between cultural parents and offspring while taking factors such as conformity bias or cultural attraction into consideration. This poster introduces the data collection app, styled as a simple transmission-chain quiz game. While answering the questions, participants are presented with tips of previous players as hints. We are able to modify the transmission parameters (e.g. selection pressure on tips in each generation or diversity of tips presented to the first generation of participants), which allows us to reliably parametrize the process of cultural transmission.

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Co-evolution of cooperative behavior, third-party punishment, and law: Simulation study based on prisoner’s dilemma game

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