Affiliation: | University of Cologne, Department of Economic and Social Psychology, Albertus-Magnus-Platz, 50923 Cologne, Germany; Director Labor and Population, RAND, 1776 Main Street, P.O. Box 2138, Santa Monica, CA 90407-2138, USA Tel.: +1 310 393 0411x7973; fax: +1 310 451 7084 |