Minoru Kitahara Graduate School of Economics, Osaka City University   Graduate School of Economics Osaka City University 3-3-138 Sugimoto, Sumiyoshi-ku Osaka, 558-8585 Japan   kitahara@econ.osaka-cu.ac.jp             JEL Areas: D7 : Analysis of Collective Decision-Making: General D8 : Information, Knowledge, and Uncertainty: General