Another protective factor was children’s intelligence. If children had higher IQ scores, this buffered the effect of divorce on internalizing problems reported by teachers and the rate of decrease in teacher- reported externalizing behaviors. Previous research has indicated that child intelligence buffers children from negative effects of divorce (Guidubaldi & Duckworth, 2001; Hetherington, 1989; Katz & Gottman, 1997; Kraynak, 1997; Wallerstein & Kelly, 1980), although the present study suggests that intelligence, and maternal sensitivity as well, may not be sufficient to fully inoculate children from problems associated with divorce, as children at age 15 still evinced behavior difficulties.