[1] Indiana Univ, Dept Psychol & Brain Sci, Bloomington, IN 47405 USA
[2] George Washington Univ, Dept Psychol, Washington, DC 20052 USA
[3] NIA, Div Behav & Social Res, Bethesda, MD 20892 USA
[4] Karolinska Inst, Dept Med Epidemiol & Biostat, Stockholm, Sweden
[5] Yale Univ, Ctr Child Study, New Haven, CT 06520 USA
[6] Penn State Univ, Dept Psychol, University Pk, PA 16802 USA