Abstract:

We are running two research projects entitled “Adolescent Sociality across Cultures: Establishing a Japan-UK Collaboration” and “Evolinguistics: Integrative Studies of Language Evolution for Co-creative Communication”. These two projects share many topics, such as life history evolution, cultural transmission, social network, communication, cognitive development, and (allo)parental investment, including general evolutionary and ecological foundations of humans. This symposium provides an opportunity to explore ideas, to build research networks, and to advance more integrated approaches. We will welcome 7 speakers (including 5 researchers based in the UK) whose talks cover several aspects of the adolescent sociality and language evolution. Organizers hope that you can enjoy this symposium like ALE beer! (or your favorite something!)

Date:

Friday, July 5th 2019 (13:00 – 18:35)

Venue:

4th Floor Hall, Science Building #2, Hongo Campus, The University of Tokyo

7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan

東京大学 本郷キャンパス 理2号館 4階 講堂（西側＝本郷通り側＝リンクの地図の下側の玄関から入り4階までお上がりください）

On Tap Today (Program):

*Abstracts are available below, and this program may be changed.

Hall opening at 12:30

13:00 – 13:05 Opening remarks by Masahito Morita (The University of Tokyo)

13:05 – 13:20 Project introduction (Adolescent sociality & Evolinguistics) by Emily Emmott (University College London) & Masahito Morita (U Tokyo)

13:20 – 13:50 Talk 1 by Emily Emmott (UCL)

Understanding adolescent sociality: photovoice as an ethological method

13:50 – 14:20 Talk 2 by Laura Brown (London School of Hygiene and Tropical Medicine / London School of Economics)

Menarche in low- and middle-income countries

14:20 – 14:50 Talk 3 by Anushé Hassan (LSHTM)

Fathers favour sons, mothers don’t discriminate: a study of sex-biased parental care in north-western Tanzania

Break for 20 min

15:10 – 15:40 Talk 4 by Yudai Tokumasu (U Tokyo)

How is sexual difference constructed, and what does it construct?

15:40 – 16:10 Talk 5 by Harumi Kobayashi (Tokyo Denki University)

The nature of human communication from developmental perspectives

16:10 – 16:30 General discussion / Moderators: Mari Nozaki (Hirosaki University) & Atsuko Saito (Sophia University)

Break for 20 min

*The below section is also a lecture for undergraduate and graduate students.

16:50 – 16:55 Speaker introduction by Masahito Morita (U Tokyo)

16:55 – 17:40 Talk 6 by Ruth Mace (UCL / Lanzhou University) [Cancelled]

The diversity of kinship systems in China, and how they shape cooperation in society

16:55 – 18:25 Talk 7 by Rebecca Sear (LSHTM)

Beyond the nuclear family: a global perspective on families and their influence on child, adolescent and maternal health

18:25 – 18:35 Summary & Closing remarks by Yasuo Ihara (U Tokyo)

*Each talk includes Q&A and switching time.

Post-symposium party:

Please contact us for details.

簡単な懇親会を設けます（学内にて立食形式・カンパ制を予定）

Organizers:

Masahito Morita*, Yudai Tokumasu, & Yasuo Ihara

Evolutionary Anthropology Lab, Department of Biological Sciences, The University of Tokyo

*mmorita.human "at" gmail.com

Sponsors:

ESRC-AHRC UK-Japan SSH Connections Grant “Adolescent Sociality across Cultures: Establishing a Japan-UK Collaboration” #ES/S013733/1

MEXT Grant-in-Aid for Scientific Research (KAKENHI) on Innovative Areas “Evolinguistics: Integrative Studies of Language Evolution for Co-creative Communication” #4903

We will take photos and record discussions for reports and publicity. Thank you for your understanding.

Titles & abstracts of talks:

*Co-authors' names are not shown here.

Understanding adolescent sociality: photovoice as an ethological method

Emily Emmott (University College London)

What is adolescence? From a life history perspective, adolescence is an interesting period of life where individuals begin to invest more in reproductive effort, with the timing of investments theorised to reflect life history strategies. From an embodied capital perspective, adolescence is also a time of continued growth, learning and intensive skills-development. In both cases, adolescence is a time of change and transition, with impact on fitness in adulthood. However, what is missing from these individual-focused frameworks is the transitions and investments in adolescent social capital (or relational wealth). This is likely to be of significance in a social, cooperative childrearing species such as humans. In this talk, I will explore the relationship between adolescent social networks and adolescent outcomes, and outline my current questions around adolescent sociality and development. I approach these questions from an ethological perspective, and introduce ‘photovoice’ as a tool to conduct ‘naturalistic observations in hidden settings’.

Menarche in low- and middle-income countries

Laura J Brown (London School of Hygiene and Tropical Medicine / London School of Economics)

Age at first period is influenced by a unique set of genetic, socioeconomic, and environmental factors and both early and late menarche have implications for health throughout the lifecourse. It is also an important variable for those who are interested in measuring human life histories. However, very little is known about changes in the timing, determinants and impacts of age at menarche in low- and middle-income countries (LMICs). This has mainly been due to a lack of suitable data. The aim of this project is to review the available evidence on the timing, determinants and impacts of age at menarche in LMICs through: 1) a systematic mapping of the relevant literature; 2) analyses of Demographic and Health Surveys (DHS) that have asked the question on age at first period; and 3) reviewing longitudinal health, demographic, and reproductive surveys to highlight gaps but also potential data sources for researchers to explore. Our DHS analysis suggests a significant decline in the age of menarche in LMICs in a short time period, with regional variations and shifting associations with wealth over time. Our literature and dataset review calls for greater inclusion of menarche questions in nationally-representative surveys. In this presentation I will discuss the results of our DHS analysis and key findings from our literature and dataset review, as well as possible implications for life history theory research. <Do not cite without the authors’ permission>

Fathers favour sons, mothers don’t discriminate: a study of sex-biased parental care in north-western Tanzania

Anushé Hassan (London School of Hygiene and Tropical Medicine)

Variation in parental care by child’s sex is evident cross-culturally. Evolutionary theory provides a functional explanation for this phenomenon, predicting that parents will favour specific children if this results in greater subsequent fitness pay-offs. Here, we explore evidence for sex-biased parental care in a high-fertility, patriarchal and polygynous population in Tanzania, predicting that both mothers and fathers will favour sons in this cultural setting. Our data come from a cross-sectional study on 808 children from two rural communities in north-western Tanzania. We focus on early childhood (under age 5), a period with high mortality risk which is fundamental in establishing later-life physical and cognitive development. Examining multiple measures of direct care provision (washing, feeding, playing with, supervising, co-sleeping, and caring for when sick) we demonstrate that fathers favour sons across multiple measures, while maternal care is both more intensive and unrelated to child sex. We find no difference in parental care between girls and boys with regards to the allocation of material resources, the duration of breastfeeding, and in terms of parental marital and co-residence status. This bias towards sons may result from higher returns to investment for fathers than mothers and local gender norms about physical care provision.

How is sexual difference constructed, and what does it construct?

Yudai Tokumasu (The University of Tokyo)

The presence and magnitudes of sexual differences in psychological attributes have recently been reported (Archer, Biol. Rev., 2019). Unraveling how these differences emerged during ontogeny may help us discover universal structures in modern societies and possible forces of sexual selection working on them. In this talk, I will discuss the following three questions relevant to adolescent studies: (1) In what psychological attributes sexual differences emerge with sexual maturity? (2) Does early pubertal maturation enhance an individual's educational success, reproductive success, or status within social hierarchy at school? (3) How do social ties and verbal behaviors change with sexual maturity? I will also briefly discuss my ongoing study about the effect of voice pitch on people's attitudes toward others.

The nature of human communication from developmental perspectives

Harumi Kobayashi (Tokyo Denki University)

Children show sensitivity to others’ cues of ostensive-inferential communication from very early age, and utilize this sensitivity for language development. Because human language evolved in face-to-face manner, a variety of non-linguistic cues such as eye gaze, gestures, and facial expression play an important role. In addition, humans use language in an efficient manner so that important information is quickly referred to and recruited from context. In the lecture, I trace the development of ostensive-inferential communication and discuss the nature of human communication. I will also discuss problems of the present IT communication including SNS that heavily depends on textual information.

The diversity of kinship systems in China, and how they shape cooperation in society [Cancelled]

Ruth Mace (University College London / Lanzhou University)

I will describe the diversity of human residence systems, and illustrate them using work I have done in the Tibetan borderlands of China. This includes some groups that are matrlineal. We examine, among other things, the role of relatedness, proximity and witchcraft beliefs in establishing social relationships in these communities. Comparisons between households and between communities reveal how post-marital residence and the related kinship systems, shape patterns of cooperation in these communities.

Beyond the nuclear family: a global perspective on families and their influence on child, adolescent and maternal health

Rebecca Sear (London School of Hygiene and Tropical Medicine)

Despite a widespread assumption that the nuclear family is normative, the family takes a number of different forms cross-culturally. The role of the father in children’s lives also varies considerably between societies. In this talk, I’ll take an evolutionary perspective to understanding health and demographic outcomes, and introduce the emerging field of evolutionary public health. I’ll then go on to assess the evidence for the hypothesis that humans are ‘cooperative breeders’, meaning that mothers require help to raise children. I’ll use data from around the world to investigate whether and how fathers and extended family members affect child and adolescent health, maternal health and female fertility. The conclusions of this work are that fathers and the extended family often have an important influence on these health and demographic outcomes, but how this influence plays out varies in different cultural and economic settings.

企画者：森田理仁・徳増雄大・井原泰雄（東京大学大学院 理学系研究科 生物科学専攻 進化人類学研究室）