[1] Univ Illinois, Dept Psychol, Champaign, IL 61821 USA
[2] Univ Calif Berkeley, Sch Publ Hlth, Berkeley, CA 94720 USA
[3] Univ Illinois, Dept Bioengn, Urbana, IL USA
[4] Univ Colorado, Dept Psychol, Boulder, CO 80309 USA
[5] Univ Delaware, Dept Psychol, Newark, DE USA