1. Department of Cognition and Action, Max Planck Institute for Psychological Research, Amalienstrasse 33, D–80799 Munich, Germany
2. School of Psychology, University of Cardiff, Cardiff CF10 3XQ, UK
3. Nijmegen Institute for Cognition and Information, University of Nijmegen, Montessorilaan 3, NL–6525 HR, Nijmegen, The Netherlands