Poster #203 - Could the End of Middle Childhood Have Special Importance in Self-control Development? A Twin Study

• In Event: 2-163 - Poster Session 08
  In Poster Session: PS 08 Section - Social, Emotional, Personality

Integrative Statement

Self-control, the temperamental tendency to control one's impulses, emotions and behavior, is nowadays widely recognized as a core element in the well-adjusted individual's personality, which enables the successful facing of many challenges along the life-course. Previous studies examined heritability and stability in self-control during young toddlerhood and across adulthood. However, less is known regarding patterns of change in heritability and stability in self-control across childhood and toward adolescence.
We studied the development of self-control from early childhood to preadolescence using a longitudinal twin design. Twins participated at the age of 3 (N=1600), 5 (N=1250), 6.5 (N=861), 8-9 (N=755), and 11 years (N=607) as part of the Longitudinal Israeli Study of Twins. At each time point mothers described each child’s self-control in a questionnaire measure. Twins’ zygosity was determined by DNA samples and when not available, by a zygosity questionnaire.
The rank-order stability of self-control was moderate during early to middle childhood and high from middle childhood to preadolescence. A growth model analysis revealed a non-linear change in the mean-levels of self-control, with an increase across ages 3 to 6.5 followed by a decrease across ages 6.5 to 11. A latent class analysis revealed four developmental trajectories: While children with the highest (~45%) and the lowest (~9%) self-control tended to maintain self-control levels along the years, the two other trajectories showed opposite intersecting non-linear patterns: an increase followed by a decrease toward preadolescence vs. a decrease followed by an increase toward preadolescence (Figure 1). A non-additive genetic effect on self-control emerged. Heritability rates were moderate and remained fairly stable across ages 3 to 6.5, then increased to high rates across ages 6.5-11. The shared environment showed no effect on the trait at any of the measurement points. Non-additive genetic factors accounted for both stability and change in self-control, while the non-shared environment contributed mostly to change. Importantly, new genetic factors that emerged around age 6.5 had little influence concurrently, but had a substantial and increasing effect on the trait in the following years (Figure 2).
Results point at the years linking middle childhood with preadolescence as a period of transition and change in self-control, which may have special importance to its development. This change may be linked to new genetic factors which emerge around age 6.5 and become increasingly influential as the child matures.

Authors

• Roni Pener-Tessler, The Hebrew university of Jerusalem
  Presenting Author

• Ariel Knafo-Noam, Hebrew University of Jerusalem
  Non-Presenting Author