A second future direction is the exploration of how genetic and environmental influences on child behavior can be traced through their influences on early responding systems. In the EGDS, we focus on three such systems that undergo significant maturation during the preschool period: emergent literacy, hypothalamic–pituitary–adrenal axis functioning, and executive functioning. Each system is influenced by genetic and environmental factors, and might thus moderate a child's effect on or sensitivity to the family environment. For example, genetic influences on executive functioning deficits might place a child at greater susceptibility to respond negatively to unstructured classroom environments, which would then increase that child's risk for developing clinical-level externalizing problems. The focus on early responding systems might allow us to capture the developmental process whereby genetic and environmental influences coalesce early in development, prior to the onset of a specific disorder. Identifying such processes linked to the early responding systems might bring us closer to identifying malleable behaviors and family processes that could serve as precursors to subsequent psychopathology. Interventions could then be structured around these known precursors to prevent the onset of clinical-level problems.
