1. Independent Researcher, Garden Flat, 127 Putney Bridge Road, London SW15 2PA, UK
2. Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
3. National Primate Research Center of Thailand, Chulalongkorn University, Saraburi 18110, Thailand
4. Division of Psychology, School of Social Sciences, Nanyang Technological University, Singapore 639818, Singapore