Japan

Conventions form an essential part of human social and cultural behaviour and may also be important to other animals. Yet, despite the wealth of evidence that has accumulated for culture in non-human animals, we know surprisingly little about non-human conventions beyond a few rare examples. We follow the literature in behavioural ecology and evolution and define conventions as behaviours that solve a coordination problem in which two or more individuals need to display complementary behaviour to obtain a mutually beneficial outcome. We review and discuss the literature on conventions in non-human primates and come to the conclusion that all the ingredients for conventions to emerge are present and therefore that they ought to be more frequently observed. We probe emergence of conventions by using a unique novel experimental system in which two baboons (Papio papio) can voluntarily participate together in touch-screen based cognitive testing and we show that conventions readily emerge in our experimental setup and that they share three fundamental properties of human conventions (arbitrariness, stability and efficiency). These results question the idea that imitation is necessary to establish conventions.

Cultural Evolution Society 2021

The experimental emergence of convention in a non-human primate

### Conference Welcome

Welcome to the third Cultural Evolution Society Conference, CES2021. In the conference, which will be held from June 9-11, 2021, about 180 researchers from East Asia, Oceania, Middle East, Europe, North and South America give presentations on their latest research advancing the evolutionary understanding of human and nonhuman animal culture.

### Schedule and Program

[![](https://assets.underline.io/uploads/markdown_image/1/image/1ef06ffd05f80957b4a5b685f63ee3ba.png)](https://www.chain.hokudai.ac.jp/CES2020/wp-content/uploads/2021/06/fullprogram.pdf)
[![](https://assets.underline.io/uploads/markdown_image/1/image/12285eb22580949635121d15d5b46325.png)](https://www.chain.hokudai.ac.jp/CES2020/wp-content/uploads/2021/06/abstracts.pdf)

**Program-at-glance**

![](https://assets.underline.io/uploads/markdown_image/1/image/c0d0d4c8fcdad49d12631574fd966ae8.png)

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### Code of conduct

See the full details of [the code of conduct](https://www.chain.hokudai.ac.jp/CES2020/code-of-conduct/).
&nbsp; 
 CES is dedicated to providing a welcoming and harassment-free conference experience for everyone, regardless of gender, gender identity and expression, sexual orientation, disability, physical appearance, body size, race, age, religion, nationality, or the presence of or care for dependents. 
We do not tolerate harassment of conference participants in any form. Conference participants violating these rules may be sanctioned or expelled from the conference at the discretion of the conference organizers.

&nbsp;
**Harassment can occur in-person or virtually, and includes, but is not limited to:**
* Comments (verbal, text, etc.) that reinforce social structures of domination related to gender, gender identity and expression, sexual orientation, disability, physical appearance, body size, race, age, religion, nationality
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* Sustained disruption of talks or other events (including “Zoombombing”)
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* Advocating for, or encouraging, any of the above behaviour 

&nbsp;
 **Inclusiveness Committee**:
&nbsp;
 To facilitate implementing the code of conduct and foster a climate of inclusion, we have developed an inclusiveness committee. Below is their contact information:
 **Hiromi Matsumae**:	matsumae.hiromi.g@tokai.ac.jp
 **Patrick Savage**:	psavage@sfc.keio.ac.jp
 **Sarah Mathew**:	Sarah.Mathew@asu.edu
 **Gmail:** inclusivenessCES2021@gmail.com
 See [more details about reporting the harassment.](https://www.chain.hokudai.ac.jp/CES2020/code-of-conduct/)

### Organizing committee

**Honorary Conference Organizer:** [Kenichi Aoki (Meiji University)](https://sites.google.com/site/kenichi1aoki/home) 

**Chair:** [Masanori Takezawa (Hokkaido University)](https://lalalarakko.github.io)

**Scientific Committee:** [Kenichi Aoki (Meiji University)](https://sites.google.com/site/kenichi1aoki/home), [Yasuo Ihara (the University of Tokyo)](https://researchmap.jp/read0209180?lang=en), [Hiromi Matsumae (Tokai University)](https://sites.google.com/site/hiromimatsumae/eng), [Naoko Matsumoto (Okayama University)](https://researchmap.jp/nmatsumoto_okayama-u), [Masako Myowa (Kyoto University)](https://myowa.educ.kyoto-u.ac.jp/en), [Hisashi Nakao (Nanzan University)](https://www.hisashinakao.com/), [Patrick E. Savage (Keio University)](https://sites.google.com/view/comp-music-lab/home)

**Local Organizing Committee:** [Yutaka Horita (Teikyo University)](https://sites.google.com/site/yhoritapage/), [Masanori Takezawa (Hokkaido University)](https://lalalarakko.github.io/), [Ayaka Takimoto (Hokkaido University)](https://lynx.let.hokudai.ac.jp/~takimoto/), [Kohei Tamura (Tohoku University)](https://researchmap.jp/7000017854)

**Inclusiveness Committee:** [Sarah Mathew (Arizona State University)](https://www.sarahmathew.net/), [Hiromi Matsumae (Tokai University)](https://sites.google.com/site/hiromimatsumae/eng), [Patrick E. Savage (Keio University)](https://sites.google.com/view/comp-music-lab/home)


![](https://assets.underline.io/uploads/markdown_image/1/image/967110a00d200a6b20d6f4fa6556ba13.png)

For attending the conference, you first need to register and pay fees from [the link here](https://www.chain.hokudai.ac.jp/CES2020/registration/). After the payment of the registration fees, you will receive a ticket, which is necessary for accessing the conference site. After the payment of the registration fees, you will receive a ticket, which is necessary for accessing the conference site

Registration fee

technical paper

Sperm whales (Physeter macrocephalus) are cetaceans with a worldwide distribution and a complex social structure. Sperm whales are members of cultural groups, called “vocal clans”. Members of a vocal clan have a distinctive suite of socially learned social calls, and do not associate with individuals from other vocal clans. However, whether vocal clan membership has implications beyond the use of a characteristic acoustic repertoire had never been tested in the Caribbean. Via a dedicated survey of sperm whales in the Lesser Antilles, we observed stark differences in vocal clan distributions across relatively small distances (<100km), with little to no overlap between them. These differences in distribution appear to relate to environmental variables with one vocal clan preferring island channels and areas of high eastward current speed and the other preferring canyons with low meridional velocity variance. Such fine-scale habitat partitioning is surprising for a species which is often referred to as an “ocean nomad” and contrasts with Eastern Tropical Pacific clans, which share habitats over much greater scales (we observe a factor of 10 difference between the movements of Eastern Caribbean and Eastern Tropical Pacific sperm whales). We hypothesize that Eastern Caribbean sperm whales are habitat specialists, with vocal clans specializing on the use of certain environmental features and maintaining this specialization through social learning. This not only highlights the need to incorporate culture in the field of conservation management, as different cultural groups have different distributions and habitat use, but also the inherent ties between culture and the environment.

Culture impacts the distribution and habitat use of sperm whales in the Eastern Caribbean

This presentation will focus on two studies which looked at how individuals learn about, maintain and transmit different aspects of their cultures. Each study sampled 100 participants from three groups in the UK (50 British nationals including Black and White British, 25 Polish and 25 South Asian immigrants which are the largest immigrant groups). Both studies used mixed-methods surveys combining quantitative questions with freelists.

We looked at 3 types of cultural groups that our participants belong to: heritage, religious and national groups. Study 1 looked at which aspects of their cultures individuals believed are important to maintain, what motivated them to do so and the consequences of not maintaining these cultural practices. Study 2 looked at the aspects of these cultures individuals believed are important to teach to children and at what age. In both studies, we looked at how individuals have been taught about their various cultures, and what cultural domains they believed their cultural groups should, or should not assimilate from others and vice versa. 
We compare how these cultural domains vary in two ways: 
1. based on the type cultural group and
2. across the three demographic groups we are sampling. 

Data analysis for these studies is currently ongoing and will be completed in time for the presentation. Preliminary findings from the two studies show that the main sources for learning about one’s culture are family (parents and grandparents), school and media (TV, music and Social media). Some of the cultural aspects that are considered important fall under categories of functional domain (e.g food and music), cooperation (tolerance, acceptance, close knit ties), tradition (language, family traditions), history (of the countries, religions and movements such as immigration) and morality.

Transmission of Cultural Domains among Immigrants and British nationals in the UK

People often attribute rumours to an individual in a knowledgeable position two steps removed from them (a credible friend of a friend), such as ‘my friend’s father, who’s a cop, told me about a serial killer in town’. Little is known about the influence of such attributions on rumour propagation, or how they are maintained when the rumour is transmitted. In four studies (N = 1824) participants exposed to a rumour and asked to transmit it overwhelmingly attributed it either to a credible friend of a friend, or to a generic friend (e.g. ‘a friend told me about a serial killer in town’). In both cases, participants engaged in source shortening: e.g. when told by a friend that ‘a friend told me ...’ they shared the rumour as coming from ‘a friend’ instead of ‘a friend of friend’. Source shortening and reliance on credible sources boosted rumour propagation by increasing the rumours’ perceived plausibility and participants’ willingness to share them. Models show that, in linear transmission chains, the generic friend attribution dominates, but that allowing each individual to be exposed to the rumour from several sources enables the maintenance of the credible friend of a friend attribution.

It happened to a friend of a friend: inaccurate source reporting in rumour diffusion

Military personnel in industrialized societies often develop posttraumatic stress disorder (PTSD) during combat. It is unclear whether combat-related PTSD is a universal evolutionary response to danger or a culture-specific syndrome of industrialized societies. We interviewed 218 Turkana pastoralist warriors in Kenya, who engage in lethal cattle raids, about their combat experiences and PTSD symptoms. Turkana in our sample had a high prevalence of PTSD symptoms, but Turkana with high symptom severity had lower prevalence of depression-like symptoms than American service members with high symptom severity. Symptoms that facilitate responding to danger were better predicted by combat exposure, whereas depressive symptoms were better predicted by exposure to combat-related moral violations. The findings suggest that some PTSD symptoms stem from an evolved response to danger, while depressive PTSD symptoms may be caused by culturally specific moral norm violations.

Combat stress in a small-scale society suggests divergent genetic and cultural roots of PTSD symptoms

The existence of sharp stone tools is sometimes used as evidence for early cultural evolution in hominins. Yet, it is an open question whether these tools required cultural transmission of their underlying know-how. The main, but previously untested, alternative is that the know-how underlying these tools was the outcome of biologically evolved abilities (adaptations/exaptations). Here we tested – for the first time – whether non-human great apes may be spontaneously able to innovate the neccessary know-how to produce and use sharp stone tools. This required us to test apes in the absence of human enculturation and in the absence of human know-how demonstrations. Eleven chimpanzees were tested in this way. All proved motivated to engage in the tasks given, but not a single chimpanzee spontaneously made or used sharp stone tools. Our results stand in sharp contrast to the positive outcomes of earlier ape sharp stone tool experiments. However, all three apes that were previously tested (one orangutan and two bonobos) had received both human enculturation and human know-how demonstrations prior to their test (even active moulding of actions was sometimes applied). Human enculturation and/or human know-how demonstrations may thus be necessary before apes acquire sharp stone tool abilities. This would suggests that sharp stone tool manufacture and use has evolved – culturally and/or biologically – in the hominin lineage after the split between Homo and Pan.

Unenculturated chimpanzees fail to produce and use sharp stone tools in the absence of know-how demonstrations

Social learning in primates has been studied experimentally for over 120 years, yet until recently these efforts focused only on what one individual would learn from a single other. Evidence of group-wide traditions in the wild stimulated a shift in the present century to recognize the collective context of social learning, with the development of broader ‘diffusion experiments’ that have illuminated the nature and limits of transmission across communities of multiple individuals and then between them. Here we describe the results of two strands within our recent experiments that further explore the collective dimensions of culture and cumulative culture in chimpanzees. The first concerns collective innovation and cumulative culture. Exposing small communities of chimpanzees to contexts incorporating increasingly challenging, but more rewarding, tool use opportunities revealed solutions arising through the combination of different individuals’ discoveries, that spread to become shared innovations. The second strand is conformity, where experiments have yielded evidence of conformist changes from habitual techniques to alternatives displayed by a unanimous majority of others, but with a curious twist akin to quorum decision making, based on only a sample of those in the community. We discuss the implications of this array of findings in the context of related studies of both other primates and non-primate species, as well as for enhancing our understanding of the extraordinary forms that cumulative culture has taken in our own species, likely built on the foundations we can infer from studies of the primates with whom we share our most recent common ancestry.

Collective Knowledge and the Dynamics of Culture in Chimpanzees

Basic vocabulary lists are a popular data type in the field of phylogenetic linguistics because of the vertical signal the data carries. Interestingly, basic vocabulary also features borrowings. The horizontal influence can be understood as a proxy for population contacts as well because loanwords into basic vocabulary are most likely acquired in intimate contact situations. This is valuable information for multidisciplinary studies aiming to integrate information on contact events from various sciences to gain a better insight into the prehistory of a population. As basic vocabulary lists are widely available, they can inform of the known contact history for large groups of languages or even whole language families making wide-scale comparison possible.

We call the contact history of a language reflected by its loanwords the borrowing profile. In our paper, we compare the borrowing profiles mediated by the basic vocabulary of six well-studied Uralic languages to the borrowing profiles of the whole languages represented by large vocabulary stocks. We show that basic vocabulary provides an informative snapshot of the borrowing profile; however, the trace of prehistoric loanword layers is emphasized in basic vocabulary. Known sociolinguistic circumstances explain the differences in the borrowing profiles of basic and whole vocabulary.

Loanwords in basic vocabulary mediate the borrowing profile of a language

What we talk about when we talk about color

Storytelling, like language, is central to human cognition: it helps us process experiences (Wilkens et al, 2005), store memories (Nelson, 1993; Schank & Abelson, 1995), and form personal identities (Young & Saver, 2001; Yuval-Davis, 2006). Previous studies have used iterated learning to examine the role of cultural transmission in the evolution of language (Smith, Kirby & Brighton, 2003; Kirby, Cornish & Smith, 2008; Kirby, Griffiths & Smith, 2014), and reveal content biases for social and survival information in the transmission of narratives (Bartlett, 1920; Stubbersfield, Tehrani & Flynn, 2014; 2017). This experiment combined the transmission chain paradigm with task-based experiments (Bahrami et al, 2010; Bjørndahl et al, 2014; Thompson et al, 1993) to test whether exposure to social survival information through narrative improves performance in a social task: a game in which participants had to learn a set of novel, arbitrary social customs to succeed. In two conditions, participants then wrote either a story or list, designed to memorably communicate the customs to the next player, forming a transmission chain (see demo here: https://bit.ly/narrative-game). Scores in the task improved over generations in both conditions, supporting the hypothesis that narratives can effectively communicate social survival information in transmission. These results are compatible with Dunbar’s (1997) social brain hypothesis, the ‘problem simulation theory of storytelling’ (Gottschall, 2012 p. 63), and previous experimental work on content biases (Stubbersfield, Tehrani & Flynn 2014; 2017). We provide an experimental paradigm which can now be adapted to target more specific questions about the evolution of narratives.

True story: Narrative as an adaptation for the communication of social survival information

Swarm Robotics, which studies collective behaviors of large populations of robots with simple embodied cognition, is an ideal testbed for studying the cultural evolution of language. Our goal is to expand existing simulations in order to explore a dominant theory in evolutionary linguistics - the self-domestication hypothesis - which suggests that reduced reactive aggression led to the sophistication of the cultural niche, enabling the complexification of languages. 

Current swarm robotics models, however, lack several crucial features that are considered prerequisites for this process. Robots are typically collaborative, homogenous, with little to no memory. To mimic self-domestication, an evolutionary advantage for prosociality needs to be introduced, and robots need to be treated as distinct individuals. 

In our model, robots explore their environment while playing a language game. Crucially, we include two novel features: (1) robot individuation: robots have a partner-specificity memory, keeping track of the outcomes of past interactions with specific robots; (2) parameterizable prosociality: robots’ tendency to interact is based on experience: successful communications between robots reduce their aggression toward each other and increase their chance to interact again. With these manipulations, community structure should emerge (robots favoring interaction with some robots over others, i.e., “in-group” bias), and different lexicons should stabilize in different sub-groups in the swarm despite their physical proximity. 

Future steps will introduce an underlying task requiring robots to cooperate using their shared language to achieve a goal. In this context, more complex language structures should evolve, demonstrating the positive feedback loop between increased self-domestication and language complexity.

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The experimental emergence of convention in a non-human primate

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