Understanding How Family Socioeconomic Status Mediates the Maternal Intelligence–Child Cognitive Outcomes Relationship: A Moderated Mediation Analysis

Abstract

In a model of moderated mediation using matched data from the 1979 National Longitudinal Survey of Youth and the 1979 National Longitudinal Survey of Youth, Children and Young Adults, I test (1) whether family socioeconomic status (SES) mediates the maternal intelligence-child cognitive outcomes relationship and (2) the extent to which this mediating impact is dependent on the level of maternal intelligence. Results reveal that the mediating impact of SES on the maternal intelligence–child cognitive outcomes relationship varies as a function of the level of maternal intelligence. The positive effect of higher SES on children's academic ability decreases as the cognitive ability of mothers increases, such that children in low IQ households benefit most from higher SES, while children in high IQ households benefit somewhat less.

Acknowledgments

The author would like to extend thanks to those who provided their insights and feedback during the preparation of this manuscript: David J. Harding, of the University of California at Berkeley, and Barbara A. Anderson, Brian A. Jacob, and Yu Xie, all of the University of Michigan–Ann Arbor.

Notes

¹While the product-of-coefficients strategy assumes that the point estimate of the indirect effect is normally distributed, this is usually not the case, even in large samples in which the expectation of the point estimate is that it tends toward normality. The standard error used to determine the statistical significance of is therefore problematic. Bootstrapping overcomes the problems associated with the product-of-coefficients strategy by quantifying the indirect effect as the product of the mean bootstrapped sample estimates of the regression coefficients, with the optimum lower limit of bootstrap resamples being 5,000. Confidence intervals are produced using the estimated standard error of the mean indirect effect, and ranges excluding zero signify that mediation exists.

Figure 2. A model of simple mediation.