1. Department of Economics and Center for the Study of Rationality, Hebrew University of Jerusalem, Mount Scopus, Jerusalem 91905 (e-mail: )
2. Department of Economics, Northwestern University, 2001 Sheridan Road, Evanston, IL 60208, and School of Economics, Tel Aviv University (e-mail: )
3. Department of Economics, Boston University, 270 Bay State Road, Boston, MA 02215 (e-mail: ).