This material has been published in Jurnal of Economic Behaivor and Organization, Vol. 64, 2007, pp. 406-425,
the only definitive repository of the content that has been certified and accepted after peer review. Copyright
and all rights therein are retained by Elsevier. This material may not be copied or reposted without
explicit permission. (Copyright (C) 2008 by Elsevier Inc.).

By Frank H. Page and Myrna Wooders

(Published electronically June 18, 2008)