Using the Flanker Task to Examine Genetic and Environmental Contributions in Inhibitory Control Across Early Childhood

• In Event: Poster Session 10
  In Poster Session: PS 10 Topic - Attention, Learning, Memory

Abstract

Inhibitory control (IC), the regulation of impulses and suppression of goal irrelevant stimuli (Gagne et al., 2018; Tiego et al., 2018), is an important predictor of cognitive and socioemotional development (Rothbart & Bates, 2006). Research exploring the stability and etiology of IC in the early childhood is mixed – even within the same sample. When assessed the parent-ratings across ages 2 and 3, IC was stable and heritable at both ages. However, when assessed with the Lab-TAB (Goldsmith et al., 1995), IC showed no stability and was heritable only at age 2 (Gagne & Saudino, 2016). The lack of heritability of IC at age 3 is puzzling in light of the fact that cognitively-based measures of IC in older children are significantly heritable (Polderman et al., 2009). One possible explanation is that the Lab-TAB measure reached ceiling at age 3, hence more complex measures of IC might yield different results. This is the first study to explore the heritability of IC in young children using a cognitively-based Flanker task. In addition, we examine genetic and environmental contributions to stability across early childhood.
Methods. The sample comprised 275 same-sex twin pairs (MZ = 112, DZ = 163) assessed within one month of their 3rd, 4th, and 5th birthdays. IC was assessed with the Flanker task in the NIH Toolbox Early Childhood Cognitive Battery (Zelazo et al., 2013). This computerized task requires the child to focus on a target stimulus and inhibit their attention to distracting signals on the screen.
Results. IC displayed low-moderate stability (ranging from .11 to .24). Longitudinal trivariate Cholesky models were applied to our data to estimate genetic, shared and nonshared environmental influences on IC in each age, and the covariation across age. IC was significantly heritable at each age (h2: age 3 = .36; age 4 = .36; age 5 = .35). No significant shared environmental influences were observed. Nonshared environments accounted for the remaining variances. There were genetic effects that persisted from age 3 to ages 4 and 5, novel genetic effects emerged in age 4 and persisted to age 5, and also novel genetic effects on IC at age 5. Specifically, 87% of the genetic effects of age 4 were independent of age 3, and 50% of the genetics effects at age 5 were independent of those at prior ages.
Discussion. Cognitively-based inhibitory control shows stable and significant heritability from age 3 to 5. Genetic effects contribute to both stability and change in inhibitory control across age. The finding of significant heritability with the Flanker task at age 3 suggests that the lack of heritability for the Lab-TAB measure at age 3 is methodological.

Authors

• I-Tzu Hung, Boston University
  Presenting Author

• Jody M. Ganiban, George Washington University
  Non-Presenting Author

• Kimberly J Saudino, Boston University
  Non-Presenting Author