Toxic Stress: Implications for Policy & Practice

An Interview with Developmental Psychologist Megan R. Gunnar

And there’s another danger of chronic or severe stress. Toxic stress, we think, can shift the brain into surviving in a way that’s more rigid and less adaptive—indeed, maladaptive. There’s a really powerful illustration of this in current research of maltreated children by Seth Pollak at the University of Wisconsin. He’s showing how children who have been physically maltreated at very young ages experience actual biological changes in the brain—changes which alter the way their brain processes social threat messages, such as those conveyed by anger expressed in the face and voice of others, even years later. He uses a push-button simulation game, which asks kids to identify pictures of three different facial expressions—happy, fearful and angry—and painlessly monitors the electrical response in their brain. Some of the pictures show full-blown expressions of each emotion. But using a morphing program, he also degrades the expressions so some are blurred or ambiguous. Compared with other children, those who’d suffered severe physical abuse “see” the anger face when other children still aren’t sure what expression they are looking at in the blurred image.

The findings suggest that their “neural category” for anger—the way their brain processes things like facial expressions and voices—has been biologically altered. Now, that might serve as an important adaptive response—alerting vulnerable kids to a threatening situation and helping them avoid getting walloped. But it can also serve the opposite purpose—predisposing kids to imagine anger and creating possible conflict when they get bumped in the hallway, for example, and perceive threat when there is none.

How are youngsters most affected by early stress?

The effects are varied and quite broad. The fact is that we’ve focused so much of our attention on the cognitive effects of early stressors—from exposure to cocaine, from malnutrition, just go down the list—that we’ve been really focused on the cognitive outcomes. But what we’re beginning to see is that things like emotion processing and social behavior are also fundamentally affected by these early toxic stresses. (See the Pollak research, for example, above.)

Can you identify a few ways in which the science of brain development—and your research specifically—should have an impact on public policies in this country?

It’s very clear that our research findings reinforce at a biological level much of what we’ve been saying about environments for young children for a long, long time. The policy implications are far-reaching. The science tells us, for example, that we really need high-quality care for young children. We really need sensitive, responsive, individualized and continuous relationships with the most important people in our children’s lives, whether parents or professional caregivers. And we really need good child nutrition. So these findings have implications for all sorts of public policy decisions—­everything from the way we structure our nation’s child-care system and invest in high-­quality programs, to the way we treat vulnerable youngsters in foster care.

What we’re demonstrating with science is that these influences really do have the capacity to affect brain architecture. It’s not just some ephemeral, abstract notion about what’s good for the growing child. In recent years, everything we’ve seen through the science only reinforces the urgent need to focus on early childhood development—and to not shortchange it thinking we can somehow compensate later.

What do we know now that we didn’t just a few years ago to make these scientific observations more compelling?

So many things. There’s tremendously new and exciting knowledge about the brain’s “plasticity,” its ability to be shaped or sculpted, for example, and about the complexity of the frontal cortex.

There’s a new frontier regarding how genes are regulated, and exciting work about the processes early in development that can permanently “silence” genes. And we’re learning more about how, on a molecular level, social experience can enter the picture and really alter gene expression [by] turning “on” and “off” the genes we’re each carrying. We’ve seen all this in animals, and we know it’s extremely unlikely that it’s happening in one species and not in our own.

The interviewer: Dorian Friedman is the policy editor at The American Prospect, a monthly political magazine, and a former associate editor at U.S. News & World Report. She has worked to advance beneficial social policies and effective communication strategies with the FrameWorks Institute, the Welfare to Work Partnership, and other nonprofit organizations. She is based in Washington, D.C.

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