Ego Functions and Ego Development: Defense Mechanisms and Intelligence as Predictors of Ego Level

This study considers the contribution of two ego functions—intelligence and defense mechanisms—to ego developmental level. Two independent assessments of ego level were related to IQ and defense mechanism use in a sample of 89 young adults. Whereas IQ and defense were themselves found to be unrelated, both variables predicted ego level: The relation with IQ was linear, whereas the relation with defense was curvilinear. In addition, the relation between defense and ego level varied as a function of IQ level. At low levels of IQ, stronger use of Denial and Projection was associated with higher ego levels. At high IQ levels, strong use of Denial was associated with lower ego levels, whereas moderate use of Projection was associated with higher ego levels.