Brain research tells us that children’s early experiences affect the physical architecture of the brain. Playful, loving, language-rich interactions between parents or caregivers and young children have a positive impact on the wiring of the young brain, laying the foundation for literacy and other healthy development. Conversely, toxic stress – stress so unrelenting the body doesn’t return to a calm baseline – has a deleterious affect on children’s growing brains and bodies.

This is the science behind a new policy on toxic stress adopted recently by the American Academy of Pediatrics (AAP). Among the authors of the new policy is Dr. Jack Shonkoff, the pediatrician who heads the Center on the Developing Child at Harvard and whose landmark 2000 book “From Neurons to Neighborhoods” helped revolutionize the way we think about the complex relationship between nature and nurture. (See above video of a forum at the Harvard School of Public Health with Shonkoff, AAP President Robert Block, and Roberto Rodriguez, White House special assistant to the president on education policy. Read Boston Globe interview with Shonkoff.)

“Toxic stress might arise from parental abuse of alcohol or drugs,” Nicholas Kristof writes in The New York Times. “It could occur in a home where children are threatened and beaten. It might derive from chronic neglect — a child cries without being cuddled. Affection seems to defuse toxic stress — keep those hugs and lullabies coming! — suggesting that the stress emerges when a child senses persistent threats but no protector.

“Cues of a hostile or indifferent environment flood an infant, or even a fetus, with stress hormones like cortisol in ways that can disrupt the body’s metabolism or the architecture of the brain. The upshot is that children are sometimes permanently undermined. Even many years later, as adults, they are more likely to suffer heart disease, obesity, diabetes and other physical ailments. They are also more likely to struggle in school, have short tempers and tangle with the law.”

The new policy calls for an active role for pediatricians beyond the examining room.

“As trusted authorities in child health and development, pediatric providers must now complement the early identification of developmental concerns with a greater focus on those interventions and community investments that reduce external threats to healthy brain growth,” the AAP policy states. “To this end, AAP endorses a developing leadership role for the entire pediatric community—one that mobilizes the scientific expertise of both basic and clinical researchers, the family-centered care of the pediatric medical home, and the public influence of AAP and its state chapters—to catalyze fundamental change in early childhood policy and services.”