1 Institute of Cognitive Science, University of Osnabrück, Germany. Electronic address: fjaekel@uos.de.
2 Department of Psychology and Center for Cognitive Science, Rutgers University, New Brunswick, NJ, USA.
3 Neural Information Processing Group, Faculty of Science, and Bernstein Center for Computational Neuroscience Tübingen, University of Tübingen, Germany; Max Planck Institute for Intelligent Systems, Empirical Inference Department, Tübingen, Germany.
4 Laboratory of Psychophysics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Switzerland.