DISENTANGLING THE IMPACT OF PRENATAL AND POSTNATAL EARLY LIFE STRESS ON PUBERTAL TIMING AND ADOLESCENT AGGRESSION

According to evolutionary-developmental theories, experiences of early life stress (ELS) accelerate child development to increase the chances of being able to thrive in a harsh environment. Children exposed to ELS often experience earlier pubertal timing and are at a greater risk of developing later risk behaviors in adolescence. However, the extent to which ELS at different sensitive periods (e.g., prenatal or postnatal ELS) predicts pubertal timing is not understood, nor are the mechanisms linking ELS to specific risk behaviors, such as aggression. The current study aims to add to the literature by simultaneously examining the impact of prenatal ELS (measured via perinatal risk factors) and postnatal ELS (measured via early environmental harshness) on pubertal timing, investigating the impact of both types of ELS on adolescent aggression through earlier pubertal timing, and exploring sex differences among these effects. Data collected on 561 adopted children and their adoptive parents and birth parents from infancy through age 15 were used to test the following research questions: 1) How do perinatal risks and early environmental harshness, both individually and in combination, predict pubertal timing?; 2) How do perinatal risks, early environmental harshness, and pubertal timing predict aggression?; and 3) What sex differences exist in the relations among perinatal risks, early environmental harshness, pubertal timing, and aggression? Contrary to study hypotheses, results revealed no significant effect of perinatal risks or early environmental harshness on adolescent aggression. Pubertal timing did not mediate the link between either type of ELS on adolescent aggression. Additionally, sex was not a significant moderator of those results. Post hoc exploratory analyses showed that an unpredictable postnatal environment (a different operationalization of postnatal ELS) did significantly predict pubertal timing, but not adolescent aggression. This result was significant for males and females. These findings suggest that unpredictable ELS may be an important factor related to fast life history strategies, and that outcomes associated with fast life history strategies may not encompass aggression as a risk-taking behavior that can be explained with life history theory