Psychological maturity and change in adult defense mechanisms

Change in the use of defense mechanisms between late adolescence and adulthood was assessed in two different longitudinal studies from the Institute of Human Development. The results were virtually identical: the use of Identification decreased, the use of Denial increased, and there was little change in the use of Projection. Both the use of Identification at adolescence, and its subsequent decrease in adulthood were found to be predicted by ego strength and committed Identity - that is, by evidence of developmental maturity at late adolescence. The decrease in Identification is consistent with predictions from the theory of defense mechanism development: defenses are related to developmental period; once that period is concluded, the use of the related defense declines.