10.1177/0272431603260920 ARTICLE JOURNAL OF EARLY ADOLESCENCE / February 2004 Hennighausen et al. / EGO DEVELOPMENT Adolescent Ego-Development Trajectories and Young Adult Relationship Outcomes Katherine H. Hennighausen Stuart T. Hauser Harvard Medical School Rebecca L. Billings Judge Baker Children’s Center Lynn Hickey Schultz Harvard University Joseph P. Allen University of Virginia Adolescent ego-development trajectories were related to close-relationship outcomes in young adulthood. An adolescent sample completed annual measures of ego development from ages 14 through 17. The authors theoretically determined and empirically traced five ego-development trajectories reflecting stability or change. At age 25, the sample completed a close-relationship interview and consented for two peers to rate the partici- pants’ego resiliency and hostility. Participants who followed the profound-arrest trajec- tory in adolescence reported more mundane sharing of experiences, more impulsive or egocentric conflict-resolution tactics, and less mature interpersonal understanding in their young adult relationships, and their young adult peers described these participants as more hostile. Participants who attained or maintained higher levels of ego develop- ment in adolescence reported more complex sharing of experiences, more collaborative conflict-resolution strategies, and greater interpersonal understanding, and their young adult peers rated them as less hostile and as more flexible. Keywords: ego development; close relationships; longitudinal research In Loevinger’s model of ego development, as children develop into adoles- cents and adults, they can hold increasingly complex orientations to the self and to the interpersonal world (Loevinger 1976, 1993). These orientations 29 This study was funded by grants from the National Institute of Mental Health to Stuart T. Hauser (NO. R01 MH44934-03) and to Katherine H. Hennighausen (No. T32 MH 016259). Journal of Early Adolescence, Vol. 24 No. 1, February 2004 29-44 DOI: 10.1177/0272431603260920 © 2004 Sage Publications