1. Max Planck Research Group for Comparative Cognitive Anthropology, Max Planck Institute for Psycholinguistics, PO Box 310, 6500 AH Nijmegen, The Netherlands
2. Max Planck Research Group for Comparative Cognitive Anthropology, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany
3. Department of Psychology, University of Portsmouth, King Henry I Street, Portsmouth PO1 2DY, UK
4. Department of Psychology, Gonzaga University, AD Box 56 Spokane, WA 99258-0056, USA