Arne Robert Weiss University of Erfurt   Nordhaeuser Str. 63 Lehrgebaeude 1 Erfurt, Thuringia 99096 Germany   arne.weiss@uni-erfurt.de   http://www2.uni-erfurt.de/mikrooekonomie/weiss2.html           JEL Areas: D7 : Analysis of Collective Decision-Making: General C9 : Design of Experiments: General