1. Department of Basic Science, Graduate School of Arts and Sciences, University of Tokyo, Meguro, Tokyo 153-8902, Japan
2. Computational Group Dynamics Collaboration Unit, RIKEN Center for Brain Science, Wako, Saitama 351-0198, Japan
3. BirthRites Lise Meitner Research Group, Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig 04103, Germany
4. The Niels Bohr Institute, University of Copenhagen, Copenhagen 2100-DK, Denmark
5. Universal Biology Institute, University of Tokyo, Meguro, Tokyo 153-8902, Japan