1. Graduate School of Systematic Neurosciences, Ludwig-Maximilians-Universität, 80539 Munich, Germany
2. Department of Psychology, Peking University, Yiheyuan Road 5, 100871 Beijing, P R China
3. Human Science Center, Ludwig-Maximilian-Universität, Goethestrasse 31, 80336 Munich and Parmenides Center for the Study of Thinking, Kardinal-Faulhaber-Strasse 14a, 80333 Munich, Germany