Grant: Project Grant

"Terrible twos" is a well-known idiom and for good reasons; children start exploring their environment, occasionally in a perilous manner, have tantrums and anger outbursts when frustrated. In response, parents use coercion and harsh behaviors in varying extent to shape their children's capacity to regulate their emotions and inhibit unwanted behaviors. Harsh parenting peaks during the preschool years. However, the more these parental practices are used, higher socioemotional-behavioral problems tend to be. This association may be explained, in part, through disruptions in the secretion of the "stress hormone" cortisol, which can have damaging effects on the developing brain. Some children may also be more affected by harsh parenting, depending on individual and family factors, including their own cortisol secretion. Yet, existing evidence supporting these hypotheses remains elusive in humans. Our project aims to clarify the associations during the preschool years, and to robustly test for whom (sex, parental perceived' gender, temperament) and under which circumstances (family support, parental stress) harsh parenting is more likely to affect socioemotional-behavioral problems. We seek funding to measure cortisol levels in hair when the children participating to the Growing Up in Québec Study, a population-based sample of 4,000 children born in Québec in 2020-2121, will be 1½, 2½, and 3½ years, and for whom home visits and other measures have been funded by the Government of Quebec and its partners. Results will 1) advance knowledge on how harsh parenting affects children's socioemotional-behavioral problems; 2) inform prevention research on whether we should target stress biological pathways to mitigate the impact of harsh parenting on children; and 3) determine for whom and in which family contexts these associations are exacerbated (of buffered) to allocate more effectively our limited resources.