Japan

Humans live in complex niches where survival and reproduction are conditional on the acquisition of knowledge. The rate at which individual knowledge is acquired depends on many factors, both physical and behavioral, such as the frequency of learning opportunities. Here, we developed a series of Bayesian latent-knowledge models to estimate individual knowledge, and to infer the influence of age, as well as the physical and social environment on such knowledge. We fit these novel latent-knowledge models using a set of interviews with 94 children of different ages (4-26 years of age) on the Island of Pemba, Zanzibar, focusing on their knowledge of the local environment, such as animals and plants, in a population in which many children forage for natural resources. Preliminary results indicate that—compared to previous studies—our latent-knowledge models facilitate a far clearer picture of the intrinsic and extrinsic dynamics underpinning individual knowledge acquisition, and the life history of cultural knowledge more broadly.

Cultural Evolution Society 2021

Development of knowledge of the environment in a population of child part-time foragers

### 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”)
* Inappropriate physical contact or unwelcome sexual attention
* 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

We conducted the largest multiple-iteration retelling study to date with two different studies that 1) test how happiness and sadness are transmitted across retellings, using participant-generated stories and 2) make an exploratory comparison between the transmission of happiness and sadness and disgust, risk, embarrassment, using researcher-generated stories. We recruited 12,840 participants and examined data from 19,086 retellings over three iterations. Using a novel Bayesian model that tracks changes over multiple retellings, both studies reach the conclusion that retelling preserves the story’s degree of happiness and sadness with a high degree of precision, even when length shrinks and aspects of story coherence and rationalization deteriorate. This finding partly goes against Bartlett’s (1932) influential work that stresses increased rationalization in serial reproduction. Our exploratory comparative study found that embarrassment is also well transmitted, while disgust and risk were poorly transmitted. We propose a story-emotion model of retelling. We suggest that in a happy or sad story, people process the story by encapsulating the events and details into an overall story emotion. In retelling, the recalled story emotion provides the starting point for reconstruction and guides the selection, invention, assembly, and ordering of the story elements. Hence, we posit that thematic or story emotions, especially happiness and sadness, operate as anchors for remembering and retelling stories.

Serial Reproduction of Narratives: Happiness and Sadness Survive While Coherence Suffers

Conformity has been defined as a bias to copy the majority. This definition may not match recent research suggesting that social-learning strategies flexibly guide who, what and when to copy. This study therefore investigates the flexibility of frequency-dependent social-learning strategies across 3 domains: when learning asocial skills, social norms and cooperation. 316 participants played an economic game with a payoff matrix designed to imitate the learning of either asocial skills, social norms or cooperative norms. Participants saw the choices made by a group who had previously played the games. We investigated whether the participant would adjust to this frequency-dependent social information based on (i) whether the group learned a similar or different game-type to the participant and (ii) the reliability of this similarity information. The similarity information could be reliably correct, uninformative, or reliably incorrect. This range reflects instances when traits suggesting similarity on observable traits may not predict who is actually similar to oneself on unobservable traits. The participants adjusted their frequency-dependent social-learning strategies to both the similarity and reliability information when learning an asocial skill and a social norm, though performed better when learning from reliably similar others. The participants adjusted more to similar others when learning to cooperate, which suggests a strong in-group preference when learning cooperative norms. Together, these results contrast the view that conformist learners are biased to ‘always follow the majority’ and instead suggests that the decision to conform remains flexible to various social cues about who we may be conforming to.

Biases or balancing act? Investigating the flexibility of conformity

In cultural evolution, solutions have always been found by humans and transmitted to other humans. Advances in artificial intelligence have created systems that appear to bypass human cultural evolution. AlphaZero beat Go masters without learning from human play. Consequently, the behavior demonstrated by such algorithms can avoid the biases shown by humans and maintained via social learning. In this work, we explore the hypothesis that humans can learn novel strategies from algorithms via social learning and that these strategies can be further culturally transmitted to other humans. 
We ran a preregistered online transmission chain experiment where we mix human and machine players and measure the performance of human-only and hybrid chains. We use a planning task where humans are known to show a suboptimal decision strategy. Participants solved the task in chains, with each participant seeing the solution of the previous participants. In half of the chains, we replaced a single participant with an algorithm that used a strategy opposite to humans. We found that people immediately playing after the algorithm benefited from it, but people further down the chain reversed back to their biased strategy and lost what was gained via hybrid social learning. We discuss the boundaries of successful hybrid social learning and the possible mechanisms behind our findings.
We address with this work a novel hypothesis in cultural evolution, namely that artificial agents can actively contribute to the discovery of new solutions and we present transmission chains as a tool to investigate hybrid cultural transmission.

Hybrid social learning in human-algorithm cultural transmission

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.

Cultural evolution of football tactics: strategic social learning in managers’ choice of formation

The degree of musical diversity within and between societies is a topic of long-standing debate. Alan Lomax’s Cantometrics project made it possible to quantitatively analyse the musical features of cross-cultural societies through 37 standardized musical features (nasality, text repetition, rhythm, tonal blend, etc). The Cantometrics database provides the opportunity to look into the variation in traditional Indian vocal music using these Cantometric features for 207 traditional songs from 32 Indian societies. Principal Component Analysis identifies vocal complexity as the primary factor shaping musical variation in India, consistent with Lomax’s previous findings in global variation. Using the AMOVA (Analyses of Molecular Variance) framework, we find only minor musical differences (~1% to ~5% of variation ) on average between speakers of different language families (Indo-European, Dravidian, and Austro-Asiatic), but greater variation (11% to ~25%) between societies within language families , This supports previous findings of greater diversity within than between societies, and contributes to debates about the evolution of diversity in music and other forms of culture. Our study also highlightshow quantitative analysis can be strengthened by observations from musicians with direct experience of local traditions and applied to local/regional questions in cultural evolution.

Musical diversity within and between societies in India

Prominent theories of the evolution of human musicality have argued for the importance of collective, synchronous music-making, e.g., in social bonding or in advertising coalition strength to other groups (e.g., Savage et al., in press, Mehr et al., in press, Behavioral and Brain Sciences.) Yet these theories have not addressed the fact that there are traditional cultures (including hunter-gatherer groups) where this type of musical behavior is rare or absent, and in which music-making is primarily a solo behavior. Why is collective, synchronous music prominent in some cultures but largely absent in others? We recently offered three hypotheses to account for this variation (Patel & Von Reuden, in press, Behavioral & Brain Sciences): 1) Music-making is less likely to be collective where there is less collective action in general; 2) Music-making is less likely to be collective where it is a principal means of conveying expert knowledge or individual accomplishment; 3) The adoption of certain musical styles (e.g., timbre-based music) can constrain subsequent adoption of collective music-making. We have begun gathering information on cultures that emphasize solo music-making in order to test these hypotheses. This presentation will focus on methodological issues which need to be addressed in coding these data, including the challenge of categorizing different types of collectivity in music-making, as there are numerous types of coordination between individuals during musical activities across traditional cultures.

Accounting for cross-cultural variation in collective music-making: why is music a solo performance in some traditional cultures?

Authority, an institutionalized form of social power, played an essential role in the evolution of large-scale societies during the Holocene. Religious and political authority both have deep histories in human societies, but the nature of their relationship is contested. We purpose-built an ethnographic dataset of 97 Austronesian societies and used phylogenetic methods to address two longstanding questions about the evolution of religious and political authority: firstly how and to what extent these two institutions have co-evolved, and secondly the order in which more differentiated and less differentiated systems of religious and political authority have tended to evolve. We found very strong evidence for mutual interdependence between religious and political authority, as well as evidence against a progression from more differentiated to less differentiated systems of religious and political authority. Our results provide insight into how political and religious authority have worked synergistically to drive the evolution of large-scale societies.

Coevolution of religious and political authority in Austronesian societies

Ritual protocols aimed at rainmaking have been a recurrent sociocultural phenomenon across societies and throughout history. Given the fact that such protocols were likely entirely ineffective, why did such they repeatedly emerge and persist, sometimes over millennia even in populations with writing and record keeping? To address this puzzle, many scholars have argued that these protocols were not instrumental at all, and that their practitioners were not really endeavoring to employ them in order to bring about rain. Here, taking advantage of the wealth of historical records available in China, we argue to the contrary: that rainmaking is best viewed as an instrumental, means-end activity, and that people have always placed strong emphasis on the outcomes of such activities. To account for persistence of rainmaking, we then present a set of cultural evolutionary explanations, rooted in human psychology, that can explain why people’s adaptive learning processes did not result in the elimination of ineffective rainmaking methods. We suggest that a commitment to a supernatural worldview provides theoretical support for the plausibility of various rainmaking methods, and people often over-estimate the efficacy of the rainmaking technologies because of statistical artefacts (some methods appear effective simply by chance) and under-reporting of disconfirmatory evidence (failures of rainmaking not reported/transmitted).

Magic and empiricism in early Chinese rainmaking: A cultural evolutionary analysis

Despite advances in the study of non-human animal tool behaviour, the sources of tool-use behaviours are still debated. Often, different social and individual learning variants are assumed to play a role in behaviour acquisition. However, without the use of experimental controls, it is impossible to pinpoint which type of learning is responsible for the behaviour in question. We argue that this issue should be addressed with recourse to experimental approaches rooted in classic ethology. Building on the pioneering work by the founders of Ethology (e.g., Nikolaas Tinberg and Konrad Lorenz), we suggest that baseline experiments must be carried out before conclusions can be drawn on the role of any type of learning mechanism in the acquisition of behaviours. For example, we carried out a baseline study on the mechanisms behind nut-cracking in orangutans. We tested 12 naïve, captive, unenculturated orangutans, across two testing institutions (Leipzig: Pongo abelii; Mage=20.3; age range=10-34; 4F; Zürich: 6 Pongo abelii and two Pongo pygmaeus; Mage=14; age range =2-30; 5F). The subjects were provided with the materials necessary for nut-cracking, and no demonstrations and/or training beforehand. Out of the twelve orangutans, at least four individuals, one from Leipzig and three from Zürich, spontaneously expressed nut-cracking with a wooden hammer in the baseline. These results suggest that the behavioural form of nut-cracking can emerge in orangutans through individual learning and non-copying social learning mechanisms.

What would classic Ethologists do? Examining the source of nut-cracking with naïve, unenculturated orangutans (Pongo abelii & Pongo pygmaeus)

Customary tool use by wild tufted capuchin monkeys seems to constitute behavioral traditions, i.e., to be individually acquired by socially biased learning. Social influences apparently involve attentional/motivational effects (“stimulus enhancement”), rather than imitative learning. Persistent manipulation increases opportunities for trial-and-error learning. This process can take a long time, but once proficiently successful in a given context, the use of a type of tool can be quickly generalized to new problems. The use of percussive stone tools is common in savanna populations of tufted capuchins, and where tool material is abundant, as in Serra da Capivara, can be quite diversified. This is also the only wild population where customary use of probe tools has been observed. When exposed to molasses-filled problem-boxes, after brief (unsuccessful) attempts to break them with stone “hammers”, several males quickly succeeded in using twig probes to access the molasses through the top holes. Almost three years later, when exposed to a different Plexiglas problem-box, they promptly brought some twigs. In an experiment on the innovation and diffusion of probe tools’ use in a semi-free group, after the slow and partial diffusion of probing a molasses’ problem-box, the successful individuals quickly succeeded in extracting seeds from another box, even though the probing technique involved was different (pushing). Afterwards, a distinct sort of problem-box also elicited probing attempts. Tool use generalization can facilitate the establishing of behavioral traditions not only by increasing direct individual rewards, but also by enhancing the opportunities for socially biased learning by naïve, tolerated observers.

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