Does infant negative emotionality moderate the effect of maternal depression on motor development?

Maternal depression represents an important social/environmental factor in early childhood; however, its effect on children's motor development may vary depending on the role of infants' dispositional variables. The objective of this study is to investigate the effect of the interaction between maternal depressive symptoms in the first two years of a child's life and the child's temperamental negative emotionality on motor development during this time. Using a cross-sectional study, we assessed 272 infants aged 0 to 24 months old and their mothers. We measured the following variables: maternal depression, infant's negative emotionality, and motor development. A three-way interaction effect highlights that negative emotionality in infants and maternal depression together affect children's overall motor growth trajectory. Infants with low negative emotionality display no effect of maternal depression on motor development. Conversely, infants with high negative emotionality seem to be more susceptible to the effect of maternal depression. Specifically, high maternal depression tends to foster the negative effect of infant's negativity on motor development across time, albeit not significantly. Finally, the absence of maternal depression significantly buffers negative temperament in infants. Findings highlighted the importance of integrating different perspectives when describing early motor growth. In fact, only when considering the interdependence of potential predictors their effect on the motor growth significantly emerges. Screening for early temperamental vulnerability might help in tailoring interventions to prevent maternal depression from affecting infants' motor development.