The relationship between mothers’ reports of spanking at 15 months and externalizing behavior at age 4, for temperamentally difficult and easy children, from a longitudinal study: In this research, notice that if a child was temperamentally easy, being regularly spanked during toddlerhood slightly increased the risk of having later externalizing problems. However, this discipline style had a huge negative impact on development for toddlers with difficult temperaments. Bottom line: Power assertion is poisonous for a temperamentally at-
Data from: Mulvaney & Mebert, 2007.