Project 456443

"Terrible twos" is a well-known idiom and for good reasons; children start exploring their environment, occasionally in a perilous manner, and have tantrums and anger outbursts when frustrated. In response, parents use coercion in varying extent to shape their children's capacity to regulate their emotions and inhibit unwanted or dangerous behaviors. Harsh and coercive parenting peaks during the preschool years. However, the more these parental practices are used, the more strongly they predict higher levels of socioemotional and behavioral problems. This association may be explained in part through unusually high secretion of the "stress hormone" cortisol, which can have damaging effects on the developing brain. Yet, existing evidence suffers from many limitations undermining our capacity to inform prevention research of whether we should target stress pathways and biomarkers to prevent or mitigate the impact of harsh parenting on the children's well-being. Our project proposes to describe the dynamic associations between harsh and coercive parenting and chronic cortisol secretion as they unfold during the preschool years, to test whether cortisol secretion partially explains socioemotional and behavioral problems before school entry, and to examine if sex, parental warmth, family support, or parental stress exacerbate (or buffer) these effects. We seek funding to measure cortisol levels in hair when the participating children will be 1½, 2½, and 3½ years in the Growing Up in Québec Study, a population-based sample of 4,000 children born in Québec in 2020-21 and for whom home visits and all other measures have been funded by the Government of Quebec and its partners. Results will advance knowledge on how harsh and coercive parenting affects the children's well-being, despite being commonly used in the population. Determining in which family contexts these associations are exacerbated (of buffered) will help to allocate more effectively our limited resources.