1. University of Bonn, D-53113, Bonn, Germany;
2. Behavior and Inequality Research Institute GmbH, 53113 Bonn, Germany;
3. Harvard Business School, Boston, Massachusetts 02163;
4. Maastricht University, School of Business and Economics, 6200 MD, Maastricht, Netherlands;
5. University of Pittsburgh, Pittsburgh, Pennsylvania 15260;
6. University of Munich, Munich D-80539, Germany