“…Other postnatal exposures such as abuse, neglect, or chronic stress may also affect brain development (Lupien et al, 2011) and may lead to early deficits in self-regulation (e.g., Ishikawa & Raine, 2003;Rothbart & Bates, 2006) which may, in turn, affect parent-child relations which are important for the acquisition of self-control and social skills (Bridgett et al, 2009;Choe, Olson, & Sameroff, 2013). Such patterns are important to understand given that problem behaviors such as physical aggression peak around 2 years of age , that the link between behavior problems and cognitive development becomes established later in the preschool period (Séguin et al, 2009), and that early exposure to day care (possibly through stimulation, guidance, and socialization) may offset familial risk factors in preventing the development of physical aggression (Côté et al, 2007) and help catching up cognitively by the time of school entry (Geoffroy et al, 2010).…”