This study examines the prevalence, stability, and development of physical aggression, as reported by mothers and fathers, in a sample of children initially recruited at 12, 24, and 36 months (N=2,253) and in a subsample followed up 1 year later (n=271) in a cross-sequential design. Physical aggression occurred in 12-month-olds, but significantly more often in 24- and 36-month-olds. The rates of physically aggressive behaviors increased in the 2nd year of life, and declined from the 3rd birthday onward. Stabilities were moderate for 12-month-olds and high for 24- and 36-month-olds. At the ages of 24 and 36 months, boys were more aggressive than girls. The results confirm and extend R.E. Tremblay's (2004) hypothesis about the early development of physical aggression.

The home-based intervention program Video-feedback Intervention to promote Positive Parenting and Sensitive Discipline (VIPP-SD) was tested in a randomized controlled trial with 237 families screened for their 1-to 3-year-old children's relatively high scores on externalizing behavior. VIPP-SD, based on attachment theory and coercion theory, focuses on mirroring and discussing actual parent-child interactions in six 1.5-hr sessions with individual families at home. VIPP-SD proved to be effective in enhancing maternal attitudes toward sensitivity and sensitive discipline and in promoting sensitive discipline interactions in the intervention group as compared with the control group. Moreover, in families with more marital discord and in families with more daily hassles, the intervention resulted in a decrease of overactive problem behaviors in the children. The authors conclude that VIPP-SD should become an important module in attachment-based interventions.

Background: This study investigated the occurrence, cross-informant agreement, 1-year stability, and context characteristics of externalizing behaviors in 12-month-old children, as compared to 24-and 36-month-olds. Method: In a general population sample of 786 12-month-olds, 720 24-month-olds, and 744 36-month-olds, the CBCL/1½-5 was obtained from mothers and fathers and again one year later for a subsample of 307 children. Mothers of 1,831 children also provided complete data on child, mother, and family characteristics. Results: Over three-fourths of the externalizing behaviors occurred in more than 10% of 12-month-olds, over one-third of the items in more than 25%. For almost all externalizing behaviors, the occurrence was significantly lower in 12-month-olds compared to 24-and 36-month-old children. Mother-father agreement and 1-year stability of externalizing behaviors in 12-month-old children were significant, but generally somewhat lower than in 24-and 36-month-olds. Context characteristics were related to externalizing behaviors in 12-month-olds as well as in older children. Some associations were less pronounced in 12-month-old children, but the overall pattern of correlates was similar across age groups. Conclusions: The results of this study show that externalizing behaviors in 12-month-old children merit further research and can be assessed with the CBCL in a valid way.

This study investigated the interaction of child temperament and maternal discipline in the prediction of externalizing problems in early childhood. Interaction effects were evaluated in a sample of 227 one-to three-year-old children with relatively high externalizing problems scores on the Child Behavior Checklist/1 1 ⁄2-5. Child temperament was reported by the mothers, maternal discipline was observed in a laboratory session, and child outcome measures included both mother-reported externalizing problems and observed physical aggression. Results indicate that children with difficult temperaments are more susceptible to negative discipline (i.e., they showed more externalizing problems) as well as more susceptible to positive discipline (i.e., they showed fewer externalizing problems and less physical aggression), as compared with children with relatively easy temperaments. These findings provide empirical evidence for the differential susceptibility hypothesis and suggest directions for enhancing the effectiveness of interventions aimed at reducing early childhood externalizing problems.

In this study, the concept of 'goodness-of-fit' between the child's temperament and the environment, introduced by Thomas and Chess [Temperament and Development, Brunner/Mazel, New York, 1977], is applied within the setting of center day care. Mothers and primary professional caregivers of 186 children, aged 6-30 months, participated in this study. The child's problem behaviors were assessed with the CBCL Teacher Report Form [Achenbach, T.M., Guide for the Caregiver-Teacher Report Form for Ages 2-5, Department of Psychiatry, University of Vermont, Burlington, VT, 1997]. The child's socio-emotional well-being in day care was measured with the Leiden Inventory for the Child's Well-Being in Day Care. The Infant Characteristics Questionnaire measured the child's temperament. Children with an easier temperament showed less internalizing and total problem behavior and more well-being. The results suggest that for children with a more difficult temperament, several parallel care arrangements interfere with the process of adapting to the day care setting. Also, our results indicate that in the group of children with greater availability of trusted caregivers, a more easy-going temperament was associated with more well-being. The association between temperament and well-being was not found in the group of children with less access to trusted caregivers.