1. Weaver et al propose that among rats, maternal behavior towards newborn pups influences their cortisol response to stress via epigenetic mechanisms that change the expression of glucocorticoid receptor gene for the rest of the pup’s life. They argue that because epigenetic patterns are established at specific developmental periods, there is extreme time sensitivity to when the pup is exposed to particular maternal behaviors (licking and grooming, in this case), and maternal behavior before or after that sensitive period window is not as important. Do you think this mechanism is relevant in humans? If so, what behaviors are most analogous to “maternal licking and grooming”?
- This mechanism seems conserved for humans. When thinking of early childhood adverse events – physical abuse, death, divorce, incarceration, drug abuse – these have significant impacts on outcomes later in life despite the event preceding the outcomes by decades. In terms of similar behaviors such as “licking and grooming”, there is more physical care that parents/caretakers exhibit towards their children as they become reared such as reading to the child, feeding, coddling, childcare, etc. This depends greatly on resources available to the parents.
2. Gruenewald, in contrast, emphasize the cumulative effects of SES adversity on a multi-system allostatic load measure. Do you think that the Gruenewald findings are consistent, inconsistent, or unrelated to the Weaver findings? Explain.
- I think that these findings are not entirely inconsistent, but I believe Weaver’s proposal is that the foundational impact of socioeconomic stressors occurs at youth, and will determine the allostatic load later in life. Gruenweld conceptualizes stressors as occurring throughout life, which overlooks the impact of early stressors on one’s life course.
3. Hertzmann and Boyce argue that “it is not genes or environment, nor is it genes and environment, but rather it is gene-by-environment interactions that influence developmental trajectories.” To what extent do you think that GxE interactions can contribute to major disparities along racial/ethnic, socioeconomic, or geographic dimensions?
- Where Weaver falls short is that these stressors at key points in early development will set a life trajectory of managing and processing stressors later in life. Gruenweld speaks more of allostatic load throughout one’s life course, but does not account for early childhood stressors. Hertzmann and Boyce’s argument combines aspects of both, and better develops how early exposure to stressors interplay with environmental stressors later in life, creating a dynamic interaction between the two levels of explanatory factors (early v late). For instance, they speak on page 332, the last paragraph, of how the level of neighborhood cohesiveness mitigates the threats to development early in life, pointing towards the benefit of safe neighborhoods despite early childhood trauma