1. Animal Science Department, Biomedical Primate Research Centre, 2288 GJ Rijswijk, The Netherlands
2. Department of Behavioral and Cognitive Biology, University of Vienna, 1030 Vienna, Austria
3. School of Psychology and Neuroscience, University of St Andrews, St Andrews KY16 9JP, UK
4. Unit of Physiology, Pathophysiology and Experimental Endocrinology, Department of Biomedical Sciences, University of Veterinary Medicine, 1210 Vienna, Austria