The development of defense mechanisms from pre-adolescence to early adulthood: Do IQ and social class matter? A longitudinal study

The defense use of participants in the Berkeley Guidance Study, Intergenerational Studies, University of California, Berkeley, was traced longitudinally from pre-adolescence (n = 130) to early adulthood (n = 120). Of these participants, 78 were assessed at both ages, making it possible to assess defense change. As coded from their TAT stories using the Defense Mechanism Manual [DMM: Cramer, P. (1991a). The development of defense mechanisms: Theory, research and assessment. New York: Springer], the results showed change in defense use at adulthood. Consistent with previous findings, the defense of Projection was used more frequently than Denial at both ages. However, in adulthood there was a decline in the relative prevalence of Identification and an increase in the relative prevalence of Denial. This change in defense use between pre-adolescence and early adulthood was predicted by both childhood IQ and social class.