Genetic and Environmental Influences on Executive Functioning in Middle Childhood: The Role of Early Adversity

Stressful early family experiences (e.g., unsupportive parenting) are associated with risk for later maladjustment across domains, including executive functioning (EF; Repetti et al., 2002). However, it is unknown whether... [ view full abstract ]

Stressful early family experiences (e.g., unsupportive parenting) are associated with risk for later maladjustment across domains, including executive functioning (EF; Repetti et al., 2002). However, it is unknown whether family adversity in toddlerhood impacts the heritability of EF in middle childhood. We examined whether early adversity at 30-months moderated the heritability of common and individual components of EF at 8 years. Common EF is highly heritable (Engelhardt et al., 2015), with little room for environmental input. Therefore, we hypothesized that early adversity would not moderate the common EF factor, but instead moderate individual EF components.

The sample included 208 twin pairs from the Arizona Twin Project (Lemery-Chalfant et al., 2013). Early Adversity, assessed at 30 months of age, included Parenting Daily Hassles, low perceived MOS social support, punitive punishment (Parental Responses to Child Misbehavior), home chaos (Confusion, Hubbub, and Order Scale), CES-D maternal depression, and low maternal emotional availability. EF at 8 years included the Eriksen Flanker Task, Continuous Performance Task, Digit Span Forward and Backward, and parent-reported Attentional Focusing and Inhibitory Control (Temperament in Middle Childhood Questionnaire). For both early adversity and EF, the first principal components were extracted as composites. Genetic analyses were tested on the common EF composite as well as each individual task using umx (Bates et al., 2017).

Univariate models revealed genetic influences on all individual measures and common EF, with broad sense heritability from .22 (Digit Span Backwards) to .61 (parent-reported inhibitory control). Shared environmental influences were found for the Flanker Task (.13) and parent-reported inhibitory control (.24), and E was moderate to high (.40-.73) for all measures except parent-report inhibitory control (.15) and attentional focusing (.31). Moderation of heritability was not observed in the individual tasks, but for common EF, A and E were moderated (Δχ2(1) = 3.75, p = .053), such that A was highest and E was lowest at higher levels of early adversity. At the mean of adversity, A explains 52% of the variance (31% at -1 SD, 77% at +1 SD) and E explains 41% of the variance (84% at -1 SD, 13% at +1 SD). It is possible that in low stress homes, children may have more access to individualized resources that promote EF development.

R01HD079520

R01HD086085 

Bates, T. C., Maes, H. H., & Neale, M. C. (2017). umx: Twin and Path-based Structural Equation Modeling in R. PeerJ PrePrints.

Engelhardt, L. E., Briley, D. A., Mann, F. D., Harden, K. P., & Tucker-Drob, E. M. (2015). Genes unite executive functions in childhood. Psychological Science, 26(8), 1151-1163.

Lemery-Chalfant, K., Clifford, S., McDonald, K., O'Brien, T. C., & Valiente, C. (2013). Arizona twin project: A focus on early resilience. Twin Research and Human Genetics, 16(1), 404-411.

Repetti, R. L., Taylor, S. E., & Seeman, T. E. (2002). Risky families: family social environments and the mental and physical health of offspring. Psychological Bulletin, 128(2), 330.