The Deepest Well: Healing the Long-Term Effects of Childhood Trauma and Adversity—A Transformative Guide to Understanding Childhood Trauma and Health

by Nadine Burke Harris

They found that pups of high-licker moms had lower levels of stress hormones, including corticosterone, when they were handled by researchers or otherwise stressed out. This high-licker-leads-to-low-stress effect also showed a dose-response pattern: the more licking and grooming the rat pups got, the lower their levels of stress hormones. In addition, the pups of high-licker moms had a more sensitive and effective “stress thermostat.” By contrast, pups of low lickers not only had higher spikes of corticosterone in response to a stressor (in this case, being placed in restraints for twenty minutes), they also had a harder time shutting off their stress response than did the pups of high-licker moms.