Denmark

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.

Cultural Evolution Society 2022

Effect of prestige and CREDs on intergroup aggression

prestige bias; credibility enhancing displays; dominance; aggression; intergroup conflict; cognitive science of religion; cultural evolution

### 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.

##### ***For SoMe interaction and live tweeting please tag @CulturalEvolSoc and use #CESconf2022***


#### 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 
<br><br>

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.

poster

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.

Tip for Science: New app lets you study cultural transmission of continuous traits

Archaeological and anthropological research on war has linked the taking of human body parts as trophies with transitions to sedentism, farming, and political centralization: trophies could increase status of warriors in societies with achieved inequality, project political power for leaders relying on violent coercion of internal and external populations, and were often linked with beliefs about agricultural fertility. This study tests whether institutionalized trophy-taking in war was more likely in societies 1) at intermediate levels of social complexity, 2) engaging in violent political expansion, and 3) dependent on agriculture. A dataset of 113 societies was coded from ethnographic and secondary historical/archaeological sources. Bayesian logistic regressions were used to test the likelihood of trophy-taking from the predictors, using a DAG to adjust for appropriate covariates. None of the hypotheses was supported. There was some evidence for a negative effect of social complexity (95% CI largely negative across models). This could be interpreted as less display-oriented violence in complex societies reliant on more egalitarian/cooperative ideologies. It is also possible the sample or coding was biased, such as with the measurement of social complexity, or that trophy-taking is too broad a phenomenon to be consistently associated with any of the hypothesized drivers.

A cross-cultural analysis of social complexity and the taking of human body parts as trophies during war

Introduction. This poster celebrates advances in the study of culture in non-human taxa indexed by articles appearing in the two highest profile science journals. The present century has witnessed a remarkable surge in the quality and quantity of these studies and their reception in such journals. Approach. Titles of articles on animal culture together with brief abstracts and key illustrations extracted from Nature and Science are displayed, to illustrate the range of taxa and cultural phenomena addressed. Findings. Twenty titles are available in the present century alone, a majority from just the last decade. Reports of culture cover an expanding range of species including primates, cetaceans, birds and insects. Behavioural domains are no less diverse, from mate choice to foraging techniques, vocal repertoires and migration routes. Evidence extends to gene-culture co-evolution. Implications for conservation are now under review by IUCN and UN. Conclusions. The studies collated here index the growing recognition that cultural phenomena are widespread in animals. They provide a robust and exciting platform from which to further explore the scope of culture in non-human species.

Animal Culture Studies Advance in the Pages of Nature and Science

Social primates exhibit a vast behavioural and cultural repertoire. Understanding the ontogeny of sociability in primates can bring important findings in comparative studies between human and non-human cultures. In this context, our objective was to analyse the development of the social personality of 12 wild capuchin monkeys (Sapajus libidinosus) and test if sex and monkey identity affected the social personality. We used videos recorded in the wild during the first 3 years of life of 6 males and 6 females and analysed the rate of emission of affiliative social behaviours, such as grooming, lipsmacking and others. We used GLMMs and tested the repeatability of behaviours for statistical analysis. The results showed low repeatability for monkey identity and sex as random effects The population exhibited high values of inter and intraindividual variance in the emission of behaviours, especially during the first year and a half of life, that is the infancy of S. libidinosus. The repeatability values stabilised in the juvenile period, but remained low. Our results show that social personality is not yet established in the first three years of life for these primates. Longitudinal studies following the individuals until adulthood are necessary to understand if and when personality is consolidated in capuchin monkeys.

The development of social personality in a wild neotropical primate

Religious sermons reinforce and transform the ideas and values of local communities. Prior work indicates sermons serve important functions for individuals and groups, but many key questions could not be addressed due to limited corpus size. The present research uses natural language processing on a corpus of 50,000 geo-tagged sermons from five Christian denominations delivered between 2019-2020 in the United States. We aim to understand how sermon content is associated with—and affected by—socio-ecological context. This requires two main analyses. First, accounting for spatial autocorrelation, we correlate sermon content with state-level variables, including tightness, political orientation, and prevalence of natural disasters. Second, we use event-based analyses to examine how local sermon content is influenced by natural and man-made disasters. Preliminary analyses indicate our analyses are feasible: Sermons are distributed sufficiently across states, and we have quantified the prevalence of psychologically relevant topics in each sermon. We await the results of our main analyses. It is now easy to utilize rich data sources, like transcripts, that directly capture phenomena of interest. Religious sermons are an untapped data source for scholars to examine how religious institutions transmit culture and interact with the socio-ecological environment.

How religious sermon content is associated with—and affected by—socio-ecological context: Analyzing 50,000 American sermon transcripts from 2019-2020

Introduction: Music and language are both found in all societies. But did humans evolve to make music, or is our musicality a byproduct of language evolution? Surprisingly, there remains little data on which aspects of music and language are shared or distinct across cultures, due to the limitations of automated acoustic analysis and the lack of cross-cultural datasets with human annotations. Approach: We combined objective acoustic analysis with subjective speaker annotations to compare recordings of singing, lyrics recitation, spoken description of the song, and the instrumental version across diverse languages. Findings: Pilot analyses of recordings in five languages (Japanese, English, Yoruba, Farsi, and Marathi) suggest that tempo is the feature that most strongly differentiates speech and song (song is slower), while melodic interval is most similar (both speech and song are characterized by small intervals <700 cents). Discussion: We will use a Registered Report framework to rigorously test candidate features on a sample of over 50 languages, revealing cross-culturally shared and distinct features of speech and song, and shedding light on the evolution of language and music.

Similarities and differences in a cross-linguistic sample of song and speech recordings

People are generally biased toward hearing and producing rhythms composed of simple integer ratios. However, the preference for specific rhythm structure is also significantly modulated by experience and differs across cultures (Jacoby and McDermott 2017). The role played by distinct musical experiences in developing the specific rhythmical categories remains unclear.
To address this issue we conducted a study on haptic rhythm reproduction on congenitally deaf people, that is, a population which has never have been exposed to auditory music. 20 congenitally deaf subjects (aged 18-40) participated in an experiment based on a haptic version of the iterating learning rhythm procedure(Jacoby and McDermott 2017) The rhythmical sequences were presented on the participants’ torso using a haptic strap, and subjects were asked to reproduce rhythmical sequences by tapping synchronously along with the stimuli. Each participant’s reproduction of a rhythm provided the seed for the next rhythm iteration, so that perceptual priors could be estimated.
Surprisingly, we found that the deaf individuals have rhythmic categories that are similar to those revealed in previous studies on auditory rhythm in the general population. Like hearing populations, deaf subjects exhibit a tendency toward integer ratio rhythms. Comparing to hearing US subjects, they also tended to have significantly more of the simple categories (such as 1:1:1 ratio), and significantly less complex rhythms categories (i.e.1:2:3 ratio).
Our results show that perceptual priors for specific rhythms can be developed independently of auditory and musical exposure.

Rhythm categories without auditory experience? Perceptual priors reveal by haptic rhythm reproduction in the congenitally deaf subjects.

Previous research suggested changes in anxiety and mood connected with fluctuations of progesterone during menstrual cycle. These fluctuations could in turn lead to behavioral patterns connected to heightened states of anxiety. For example, in humans and non-human animals, ritualized behavior has been linked to states of intense stress and anxiety in a range of studies. In a pre-registered (osf.io/fq7sm) longitudinal study (36 days), free-cycling female participants regularly marked their day of the cycle, symptoms connected with the menstrual cycle, levels of anxiety, and activities they performed. These activities were evaluated by independent coders on the characteristics of ritualized behavior. The main prediction of the study were that psychological changes, specifically heightened anxiety, and perceived stress during the luteal phase, would lead to both an increase in the types of ritualized behaviors and higher intensity of those behaviors. We have not observed any differences in anxiety or stress between luteal and follicular phases, but higher anxiety (independent from phase) was positively correlated with more ritualized behaviors.

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Effect of prestige and CREDs on intergroup aggression

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