Supportive early childhood environments can lessen trauma effects, new research finds

A breakthrough concept which represents common practices for our species over its 6-million-year history that bear on child development, child raising and adult behavior, known as the evolved nest (or evolved developmental niche; EDN) has been developed by Emerita Professor Darcia Narvaez of the University of Notre Dame.

The findings in the first-of-its-kind study show that positive childhood experiences can help buffer the effects of adverse childhood experiences (ACEs) on physiological health in adult women.

Published in the journal Anxiety, Stress and Coping, Emerita Professor Narvaez and her colleagues were able to show that during both relaxing and stressful conditions, EDN-history scores buffered the negative effects of ACE scores, helping women adapt to the changing contexts in more resilient ways.

To reach their findings the researchers measured EDN experience in children and adults to find out its relation to well-being, sociality and morality. The adult measure, EDN-history, is a self-reported measure of the adult’s perception of their childhood experiences — e.g., how responsive their relationships were and how much free play, affectionate touch, family togetherness and positive climate they experienced. 

The measure also asks about corporal punishment and negative home climate, which are reverse scored. The more positive aspects and fewer negative, the higher the EDN-history score will be.

After study participants self-reported on their EDN and ACE histories, researchers measured the women’s physiological regulation by monitoring vagus nerve functioning. 

The vagus nerve is a central component of the nervous system and manages many important bodily functions including digestion, respiration and heart rate. It also plays an important role in healthy functioning, including social functioning, with its impairment a sign of psychopathology. 

Vagal tone (or vagal activity) was measured during relaxing tasks — e.g., watching a serene video with butterflies — and during a more stressful task — putting together puzzles while being timed.

“Vagal tone is a measure of the heartbeat intervals correlated with respiratory cycles or spontaneous breathing,” Emerita Professor Narvaez explained. “Vagal tone is highly influenced by early life experience, with stable responsive care supporting its healthy development.”

During both relaxing and stressful conditions, EDN-history scores buffered the negative effects of ACE scores, helping women adapt to the changing contexts in more resilient ways. During the stressful condition when women needed to ramp up their stress response to focus on a challenging task, greater EDN-history helped facilitate this in a way that was not excessive — so they were not overly stressed. 

Then, when women needed to relax and calm down during non-stressful conditions, strong EDN-history also helped them adapt and self-calm.

Researchers believe that experiences of EDN in childhood may not only buffer effects of adversity but also support the physiological building blocks of health and resilience.

EDN is a way of not only promoting the positive — what children need to develop well — but also reducing the negative physiological effects of adversity and trauma, the researchers noted. It is also important because it provides an insight into a possible key path to developing adult resilience. 

“You need a healthy vagal tone to allow you to get close to someone. And, if the vagus nerve is not functioning well, you aren’t going to demonstrate as much compassion,” Emerita Professor Narvaez said. “Vagal tone has both direct and indirect effects on morality.”

The study is part of a series of studies on the long-term effects of EDN experiences and vagal regulation. In another study in the series, six-year-old children who experienced more self-directed play in the prior week, as reported by their mothers, had better vagal regulation.

“These findings are adding to converging evidence indicating that the evolved nest components are important for healthy development,” the researchers wrote. “Human psychology research should encompass an evolutionary understanding of our species’ development by examining the evolved components that support healthy development.”

To review the findings in full please see here.