Defense mechanisms predict differential lifespan change in Self-control and Self-acceptance

Individual differences in the direction of personality change over a period of 40 years for two scales of the California Psychological Inventory (CPI: Gough & Bradley, 1996) - Self-control (Sc) and Self-acceptance (Sa) - as previously identified through the use of longitudinal hierarchical linear modeling (Jones, Livson & Peskin, 2003), were studied in a sample of men and women from the Institute of Human Development Intergenerational Studies. It was hypothesized that the use of defense mechanisms, as assessed by the Defense Mechanism Manual (DMM: Cramer, 1991a), would be differentially related to change in Sc and Sa, depending on whether participants were increasing or decreasing in that trait over time. Results indicated that for participants who decreased in Sa, the use of Denial was associated with less decrease. For participants who increased in Sc, the use of Identification was associated with less increase.