Jean-Baptiste LECA JSPS post-doctoral Fellow Section of Social Systems Evolution Department of Ecology and Social Behavior Primate Research Institute Kyoto University 41-2 Kanrin, Inuyama, Aichi 484-8506, JAPAN E-mail: leca@pri.kyoto-u.ac.jp or jbtleca@yahoo.com Born: December 19, 1973 (France) Citizenship: French				JB Leca (Madison, Georgia, USA, Oct. 2007)		Yuda (Koshima, Miyazaki-ken, Japan, Feb. 2004)
EDUCATION
2002 1998 1997 1996	Ph.D. in Ethology, University Louis Pasteur, Strasbourg, France M.S. in Neuroscience, University Louis Pasteur, Strasbourg, France Primate Cognition class, B.A. in Cognitive Psychology, University Louis Pasteur, Strasbourg, France B.S. in Cell Biology, Physiology and Behavioral Neuroscience, University of Bordeaux, France
CURRENT RESEARCH
My current post-doctoral research aims at exploring the biological, social, and ecological foundations of behavioral traditions in non-human primates, as a way to better understand the role of culture in human evolution. More specifically, I am interested in the determinants of behavioral innovations as well as the constraints on their diffusion and long-term maintenance within social groups. Among the various behavioral innovations reported in Japanese macaques (Macaca fuscata), I study three behaviors: fish-eating on Koshima Island, dental flossing at Arashiyama, and stone handling in multiple troops across Japan. I use longitudinal and cross-sectional data to explore the history and assess the current prevalence of these behaviors at the group-level. I examine the factors that may have favored these innovations, including the environmental context, the individual characteristics of the innovator, and the structural and functional aspects of the behavior. Group size, kinship, and dominance are socio-demographic factors that are likely to limit the opportunities for any group member to observe the innovator, and thus constrain the diffusion or maintenance of these potential candidates for behavioral traditions. Identifying the determinants of innovations and the constraints on their propagation within social groups of non-human primates is of special interest to understanding cultural evolution in hominids. I mainly focus on stone handling (SH) behavior, a form of solitary object play consisting of the manipulation of stones by performing various behavioral patterns. Previous findings, based on long-term observations by Dr. Michael Huffman from 1979, suggest that SH is socially transmitted across generations, as a behavioral tradition in Japanese macaques. From 2003, I have been taking an integrative approach to studying SH through the combination of comparative, longitudinal, and experimental methods. To chart inter- and intra-group diversity in SH, I systematically compare the occurrence and form of this behavior in several captive and free-ranging troops of Japanese macaques. As a first step towards a cross-species comparison of the SH tradition in the genus Macaca, I conducted a preliminary study of SH in the long-tailed macaques of Bali, Indonesia. The results of my research allowed 1) to establish the comprehensive repertoire of 45 SH patterns in Japanese macaques, 2) to reveal substantial variation in SH between troops, referred to as SH cultures, 3) to show a geographic distribution of clear troop-dependent clusters of SH variants suggestive of the notion of cultural zones, based on inter-troop observation and possibly males transferring SH patterns when migrating from one troop to another, 4) to rule out simple alternative explanations for such behavioural variability, such as genetic determinants or some obvious environmental differences, 5) to indicate that group size and composition in age classes, as well as group spatial cohesion may impact the prevalence of SH, 6) to provide evidence for the role of indirect social influences in the maintenance of the tradition through the stimulating effect of SH artefacts, 7) to show that in several troops, this behavioral tradition has reached its transformation phase over a 30-year history, with an increase in the SH repertoire and an expansion of the contexts in which SH is practiced, also referred to as “ratchet effect” or “cumulative culture”, 8) to explore the complexity in the form of SH from the perspective of stone-tool use in non-human primates, 9) to argue that food provisioning by humans may be a key factor in the innovation and transformation phases of the SH tradition, and 10) to discuss the role of phylogenetic constraints and behavioral predispositions in the evolution of the SH culture in the genus Macaca. In sum, the integrative approach to studying SH emphasizes both the product (via the comparative method to assess which differences are observed in the form of behaviors) and the mechanisms (via the longitudinal and experimental methods to determine which specific processes are involved in producing such differences) of the cultural phenomenon. We draw an overall picture of rich cultural diversity in a particular type of object-play behavior in macaques, and suggest that multiple factors should be jointly considered to identify the sources of behavioral variation in animals. Our comprehensive dataset provides valuable empirical information to test predictions and fit models generated from theories about the role of cultural processes in human evolution. This research also aims to offer new insights into the role behavioral traditions might have played in the emergence of hominid material culture through stone-tool technology. The stone handling project has been conducted in collaboration with Drs. Michael Huffman and Charmalie Nahallage from the Section of Social Systems Evolution of the Primate Research Institute, as well as the assistance by Dr. Noëlle Gunst, University of Georgia, USA. My research is currently sponsored by a post-doctoral fellowship for foreign researchers and a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (JSPS).
Examples of stone handling patterns (Shodoshima, Kagawa-ken, Feb. 2005 and Arashiyama, Kyoto-ken, Jun. 2004)
Rub together (photo: N. Gunst)			Scatter (photo: N. Gunst)		Move and push (photo: N. Gunst)
Grasp with hand (photo: N. Gunst)			Cuddle (photo: JB Leca)		“Occupational hazard”
PUBLICATIONS
Journal articles published in peer-reviewed journals Leca JB, Nahallage CAD, Gunst N & Huffman MA. 2008. Stone-throwing by Japanese macaques: form and functional aspects of a group-specific behavioral tradition. Journal of Human Evolution, 55: 989-998. Leca JB, Gunst N & Huffman MA. 2008. Food provisioning and stone handling tradition in Japanese macaques: a comparative study of ten troops. American Journal of Primatology, 70: 803-813. Leca JB, Gunst N & Huffman MA. 2008. Of stones and monkeys: Testing ecological constraints on stone handling, a behavioral tradition in Japanese macaques. American Journal of Physical Anthropology, 135: 233-244. Huffman MA, Nahallage CAD & Leca JB. 2008. Cultured monkeys, social learning cast in stones. Current Directions in Psychological Science, 17: 410-414. Leca JB, Gunst N & Huffman MA. 2007. Japanese macaque cultures: Inter- and intra-troop behavioural variability of stone handling patterns across 10 troops. Behaviour, 144: 251-281. Leca JB, Gunst N & Huffman MA. 2007. Age-related differences in the performance, diffusion, and maintenance of stone handling, a behavioral tradition in Japanese macaques. Journal of Human Evolution, 53: 691-708. Leca JB, Gunst N, Watanabe K & Huffman MA. 2007. A new case of fish-eating in Japanese macaques: Implications for social constraints on the diffusion of feeding innovation. American Journal of Primatology, 69: 821-828. Leca JB, Gunst N & Petit O. 2007. Social aspects of fur rubbing in Cebus capucinus and C. apella. International Journal of Primatology, 28: 801-817. Meunier H, Leca JB, Deneubourg JL & Petit O. 2006. Group movement decisions in capuchin monkeys: The utility of an experimental study and a mathematical model to explore the relationship between individual and collective behaviours. Behaviour, 143: 1511-1527. Leca JB, Gunst N, Thierry B & Petit O. 2003. Distributed leadership in semi-free ranging white-faced capuchin monkeys. Animal Behaviour, 66: 1045-1052. Leca JB, Fornasieri I & Petit O. 2002. Aggression and reconciliation in Cebus capucinus. International Journal of Primatology, 23: 979-998. Other publications and manuscripts in review Leca JB, Gunst N & Huffman MA. In review. A first case of dental flossing in Japanese macaques (Macaca fuscata): implications for the determinants of behavioral innovation and the constraints on social transmission. Primates. Huffman MA, Leca JB & Nahallage CAD. In review. Cultured Japanese macaques – A multi-disciplinary approach to stone handling behavior and its implications for the evolution of behavioral traditions in non-human primates. In: N. Nakagawa, M. Nakamichi & H. Sugiura (eds). The Japanese macaques. Springer, Tokyo. Petit O, Gautrais J, Leca JB, Théraulaz G & Deneubourg JL. In review. Initiatiors need to recruit a quorum of followers to keep cohesion while moving. Proceedings of the Royal Society B. Leca JB & Huffman MA. 2008. Comparative and longitudinal approaches in cultural primatology: the case of stone handling behavior in Japanese macaques. Reichorui Kenkyu/Primate Research, 24 (suppl.): 11 (Abstract). Leca JB, Gunst N, Nahallage C & Huffman MA. 2007. Stone handling as a behavioral tradition in Japanese macaques (Macaca fuscata): charting inter- and intra-group diversity and investigating ecological and socio-demographic contexts of transmission. American Journal of Primatology, 69 (Suppl 1): 77 (Abstract). Leca JB, Gunst N, Nahallage C & Huffman MA. 2006. Stone handling in Japanese macaques (Macaca fuscata) : a 10-troop comparative study about a behavioral tradition. American Journal of Primatology, 68 (Suppl 1): 110-111 (Abstract). Leca JB, Gunst N, Nahallage C & Huffman MA. 2004. Stone handling as a behavioral tradition: A comparative study in nine troops of Japanese macaques (Macaca fuscata). Reichorui Kenkyu / Primate Research, 20 (suppl.): 25 (Abstract). Leca JB & Gunst N. 2000. Quand les capucins s’amusent [When capuchins have fun]. ZooMulhouse, 28: 6-7.
Other behavioral innovations or traditions in Japanese macaques: fish-eating and dental flossing (Koshima, Miyazaki-ken, Jan.-Feb. 2004 and Arashiyama, Kyoto-ken, Jun. 2008)
(photos: JB Leca)
GRANTS, FELLOWSHIPS, AND SCHOLARSHIPS
2008 2007-2009 2007-2009 2003-2005 2002 2002 1998-2002 1998-2001 1997-1998		Travel funding, Primate Origins of Human Evolution (HOPE), Kyoto University, Japan Post-doctoral fellowship for foreign researchers, Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for Scientific Research conducted by JSPS fellows Post-doctoral grant, Lavoisier, Ministry of Foreign Affairs, France Research and travel funding (Complex Systems and Non-Linear Phenomena. University of Brussels, Belgium), CNRS/CGRI-FNRS agreement (joint project: Dr. O. Petit/ Dr. J.-L. Deneubourg) Research grant, European Doctoral College, University Louis Pasteur, Strasbourg, France Teaching assistantship, University Louis Pasteur, Strasbourg, France Ph.D. fellowship, French Ministry of Scientific Research M.S. scholarship, University Louis Pasteur, Strasbourg, France
TEACHING EXPERIENCE
2001-2002		Instructor, University Louis Pasteur, Strasbourg, France
		Course taught: Elementary Neurophysiology
1998-2001		Teaching Assistant, University Louis Pasteur, Strasbourg, France
		Courses taught: Developmental Biology and Elementary Embryology, Introductory course in Ethology and Behavioral Ecology, Introduction to Primate Studies (Anthropology, Behavioral Ecology, biomedical research, conservation issues), Primate Cognition, Evolution of Reproductive and Social Behaviors, Methodology in Animal Behavior Studies
Overhanging Beppu Bay (Takasakiyama, Oita-ken, Jan. 2004)			Blanche-59-64-75-80 (Arashiyama, Kyoto-ken, May 2004)		Kusha-59-71-76-82-04 (infant female) and Mino-63-69-74-83-90 (alpha male) (Arashiyama, Kyoto-ken, Aug. 2004)