- 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”?
I do believe that this mechanism is relevant in humans and that analogous behaviors include physical contact, specifically parents holding, touching, making eye contact and talking/reading to the child.
- 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 the findings are consistent. Not only can there be there a latency relationship when there is an exposure during one critical point in time, but when this exposure happens both during the critical period and then multiple additional times over the life course, there can also be a cumulative effect. The Hertzman and Boyce article describes these relationships and how they can coexist.
- 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?
I believe that genes, the environment, and the interaction between them contribute to disparities. In particular the interaction effects make a significant contribution (at least among mammals) because the effect of natural selection. As described by Weaver, offspring may be shaped to respond to variations in parental behavior as a forecast of the environmental conditions they will face once they become independent. It’s a little woo-woo, but in some forms of spiritual teachings, there is a belief that we each hold the wounds of our ancestors, which in turn shapes our perspective and behaviors.