1. Sloan School of Management and Department of Economics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142;
2. National Bureau of Economic Research, Cambridge, Massachusetts 02138;
3. School of Management and Law, Zurich University of Applied Sciences, 8400 Winterthur, Switzerland;
4. Department of Economics, University of Fribourg, 1700 Fribourg, Switzerland;
5. Faculty of Business and Economics, University of Lausanne, 1015 Lausanne, Switzerland