Private Speech and the Development of Self-Regulation: The Importance of Temperamental Anger.

In this study (N=160), we observed children's private (i.e., self-directed) speech (PS) during a challenging puzzle task at age 3 and assessed whether the amount and maturity of their PS predicted their inhibitory control (IC) at age 4 and indirectly emotion regulation at age 9. Additionally, we examined whether the direct and indirect effects of PS were moderated by children's temperament. As expected, the maturity of children's PS was positively associated with IC and this association was stronger when children were reported as higher in anger reactivity by mothers (the interaction accounting for 11% of the explained variance). Children low in temperamental anger tend to have good IC and may not need to use PS. When children were at or above the mean on anger reactivity, PS maturity was indirectly associated with better emotion regulation at age 9 through an influence on IC at age 4 (index of moderated mediation =1.03 [.10, 3.60]). Findings suggest that PS is an important self-regulatory tool for 3-year-olds who typically experience and express anger.