1. Institute of Psychology, University of Wroclaw, Wroclaw, Poland
2. Faculty of Management, Computer Science and Finance, Wroclaw University of Economics, Wroclaw, Poland
3. Department of Sociobiology/Anthropology, University of Goettingen, Göttingen, Germany
4. Courant Research Center Evolution of Social Behavior, University of Goettingen, Göttingen, Germany
5. University of Namibia