Poster #3 - Genetic and Environmental Contributions to Developmental Trajectories of Attention in Preschoolers

• In Event: Poster Session 08

Abstract

Attention has been viewed as a multidimensional system that plays an important role in children’s knowledge acquisition and integration (Posner & Petersen, 1990; Steele et al., 2012). Attention skills in preschoolers show linear increases with age (e.g., Sarid & Breznitz, 1997). The present study uses latent growth curve models (LGCM) in a longitudinal sample of twins ages 3 to 5 years to evaluate individual differences in developmental trajectories of attention; and further, to estimate genetic (A), shared environmental (C, environments common to all family members), and nonshared environmental (E, environments unique to individuals) sources of variance on developmental trajectories.
Methods. The sample included 309 same-sex twin pairs (MZ = 123, DZ = 186) from the Boston University Twin Project who were assessed within one month of their 3rd, 4th, and 5th birthdays. Attention was assessed using observer ratings on a 5-point scale (1 = “constantly off task/doesn't attend”; 5 = “constantly attends”) averaged across 11 discrete behavioral episodes in the lab.
Results. A phenotypic LGCM provided a good fit to the data (χ2(1, N =618) = .754, p = .39, CFI = 1.00, RMSEA = .000, SRMR = .011). The mean slope was significant (µS = .18, p < .01) indicating that attention increased across age. The variance of the intercept was significant (σI = .08, p < .01) revealing individual differences in the stable component of attention across age. Although the mean level of the slope was significant, there was no significant variance around the slope (σS = .01, p = .24). A biometric growth model (see Figure 2) used to decompose the variances of the intercept and age-specific residuals into their genetic and environmental components also fit the data well (χ2(37, N =618) = 61.25, p < .01, CFI = .93, RMSEA = .065, SRMR = .095). Genetic and shared environmental influences accounted for 50% and 49% of the variance in the intercept, respectively. There were age-specific genetic effects on attention at ages 3 (38%) and 5 (57%); and age-specific nonshared environmental influences at all ages.
Discussion. Consistent with prior research, attention improves across the preschool period. The lack of variance in the slope indicates that all children within our sample showed a similar developmental trajectory and suggests universal developmental mechanisms underlying the observed change. Genetic and shared environmental influences equally explained stability in attention across the preschool period. Age differences in attention are due to genetic and nonshared environmental influences. Novel age-specific genetic effects at ages 3 and 5 may reflect maturational processes associated with brain development; however, the lack of age-specific genetic effects at age 4 is puzzling. The nonshared environmental factors that influence attention reflect unique environmental influences specific to each child at each age and hint that environmental interventions to improve attention should be individually targeted and age-appropriate.

Authors

• Yue Ma, Boston University
  Presenting Author

• I-Tzu Hung, Boston University

• Jody M. Ganiban, George Washington University

• Kimberly J Saudino, Boston University