Executive function: Components, development, and findings for minority children of low socioeconomic status

Many studies have examined executive function. However, few longitudinal studies have studied the development of executive function within a high risk, low SES inner city sample of children. This longitudinal study examined executive function in a group of 120 Low SES inner city children, half of whom were exposed to cocaine during gestation. We assessed executive function with the Goodman Lock Box at ages 3 and 4. At age 11 to 13, we examined executive function using a set of tasks designed to measure cognitive control, working memory, planning and problem solving. Child IQ was assessed at ages 4 and 6. Four specific questions were addressed. First, does prenatal cocaine exposure effect executive functioning? Second, how do these low SES inner city children perform on measures of executive function compared to normative samples? Third, what are the concurrent relationships between measures of executive function? Fourth, what are the longitudinal relationships between measures of executive function? Results indicated no significant effects of prenatal cocaine exposure on executive function. Second, the two groups combined performed on average about half of a standard deviation below the mean compared to normative samples. Third, concurrent correlations between measures of executive function varied across measures (r =.20 to .60). Finally, longitudinal correlations between measures of executive function were small (r = .22 to .23). Hierarchical Linear regression showed that Performance IQ was a better predictor of age 11 to 13 executive functioning than age 3 and 4 executive functioning. We conclude that despite overall risk associated with gestational cocaine exposure, it did not significantly impact later executive function as assessed in this study. Apparently, cocaine exposure did not substantially increase developmental risk for this sample of inner city children of low SES, all of whom were exposed to many risk factors associated with poverty known to be associated with below average performance on normative measures. Early executive function skills did predict a small amount of the variance in later skills. However, Performance IQ was more predictive of later executive function than were early executive function measures.