A new paper by Katz et al, "Prefrontal Plasticity and Stress Inoculation-Induced Resilience", shows how exposure to mild stress as a young child can actually alter the brain in ways that make us better equipped to handle future stress as adults. Parents may feel that by preventing their child from encountering any and all potential hardship they are helping to preserve their emotional well-being, but going through a little stress and encouraging them to cope with it effectively will benefit them far more when it comes to being a more resilient, independent, and emotionally stable adult. I appreciate this study not only because it provides me with scientific justification for all of the difficulties I have endured in my own life, but also because it just makes sense. I love studies that make sense.
The abstract states:
Coping with mild early life stress tends to make subsequent coping efforts more effective and therefore more likely to be used as a means of arousal regulation and resilience. Here we show that this developmental learning-like process of stress inoculation increases ventromedial prefrontal cortical volumes in peripubertal monkeys. Larger volumes do not reflect increased cortical thickness, but instead represent surface area expansion of ventromedial prefrontal cortex. Expansion of ventromedial prefrontal cortex coincides with increased white matter myelination inferred from diffusion tensor magnetic resonance imaging. These findings suggest that the process of coping with early life stress increases prefrontal myelination and expands a region of cortex that broadly controls arousal regulation and resilience.
Before you get intimidated by the neuro-speak, let me offer a brief explanation of the brain processes involved, in layman's terms:
The prefrontal cortex (PFC) of the brain is the seat of cognitive control and executive functioning, which allows us to make reasonable decisions about situations we encounter. When presented with a problem, the PFC allows us to analyze the situation, weigh the relevance of the information, and make sound decisions on how to act. People who have a poorly functioning PFC–we can use Schizophrenia as an example– are unable to make reasonable sense of the vast amounts of information in front of them, interpret situations inaccurately, and as a result, engage in maladaptive behavior. On the other hand, someone with a superior or properly functioning PFC is able to swiftly and effectively take in the same large amounts of stimuli, make appropriate judgments about the information, and thus are more likely to choose appropriate courses of action.
Myelination of axons increases the speed of transmission of information across neural connections. When we speak of white matter in the brain, we are referring to the axons, or the part of the neuron that carries the information to the next neuron, or group of neurons. Gray matter, on the other hand, refers to the neurons or nerve cell bodies themselves; an increase in gray matter volume, or cortical thickness, usually implies new neural connections, such as those resulting from learning a new skill.
In this study, exposure to stress resulted in an increase in the white matter myelination, which implies an increased speed at which the existing connections were able to transmit information in the neural networks.
So what does this mean in regards to exhibited behaviors?
In this excerpt, Katz and colleagues explain how this exposure to stress, as measured in primates and humans, translates into future coping behaviors:
Stressful experiences that are challenging but not overwhelming appear to promote the development of subsequent resilience in children. Variously described as inoculating, immunizing, steeling, toughening, or thriving, the notion that mild early life stress induces the development of resilience is further supported by longitudinal studies of non-human primates. Squirrel monkey mothers and other group members periodically leave newly weaned offspring beginning at 3-6 months of age to forage for food on their own. Initially, brief intermittent separations studied in controlled experimental conditions elicit distress peep calls and increase plasma levels of cortisol with partial habituation of these measures of arousal observed over repeated social separations. Later in life, monkeys exposed to intermittent separations show fewer behavioral indications of anxiety, increased exploration of novel situations, and diminished stress levels of cortisol compared to age-matched monkeys not exposed to prior separations. These behavioral and hormonal outcomes reflect a nonspecific form of stress inoculation as exposure to one type of early life stress enhances subsequent arousal regulation in coping with different stressors encountered later in life.
Here is what I find most interesting about this result: Contrary to what one may think exposure to stress as a child might reap in adulthood (adjustment disorders, psychopathology, etc..), instead they found the opposite effect. Youths that were exposed to stress actually had less anxiety, lower levels of stress, and had more confidence in exploring novel situations, or demonstrated an increased sense of independence.
So can exposure to stress actually be good for us? YES!
How is this possible? The study goes on to say,
"Prior exposure to separation stress also enhances prefrontal-dependent cognitive control of impulsive behavior and appears to increase ventromedial but not dorsolateral prefrontal volumes determined in vivo by non-invasive neuroimaging of the squirrel monkey brain. These findings are of interest because large ventromedial prefrontal size in humans predicts diminished impulsivity, lower harm avoidance, and greater retention of learned extinction of fear. Recent neuroimaging studies of humans support results from animal research confirming that learned extinction of fear is mediated by prefrontal down-regulation of arousal via inhibitory connections that diminish neural output from the amygdala. Additional evidence likewise suggests that differences in the balance between top-down prefrontal regulation and arousal-inducing amygdala activation may account for global trait-like differences in coping with stress. "
So what does this translate to? Basically, after coping with stress successfully, your brain says, "Hey, that wasn't too bad. I can handle this." The next time you encounter a similar-type stressful situation, your brain has already had success in coping before, so you don't feel as much emotional anxiety. You are able to assess the situation more quickly, judge the relevance of everything involved, and make more appropriate choices in how to act.
For example, giving a presentation in front of a crowd of people is generally seen as a stressful event. If you go through your entire life without ever having to stand in front of a group and present information, this could be pretty stressful if you experience it for the first time as an adult. However, after the first few times you have success with presenting (you don't go into cardiac arrest, people don't throw rotten veggies), the anxiety gradually lessens, and hopefully, in the future these types of presentations won't be as anxiety-provoking.
Now imagine that as a child, you were encouraged to engage in activities that forced you to be in front of adults and present an idea or a skill, whether it were joining a debate club, or participating in a play, a dance recital, or a musical assembly. Yes, it might be excruciatingly painful and anxiety-provoking to do it for the first time, and watching your child go through that agony might be just as painful for you. But the more often he engages in the activity and successfully copes with the stress of performing in front of a crowd, the more confidence he is building, and the more resilience he will have in facing these types of situations as an adult. Additionally, he will be better able to manage his emotions surrounding a stressful event, and less likely to suffer debilitating anxiety as a result. To be clear, I am not merely talking about "getting used to the pain of embarrassment and humiliation." I am talking about making positive changes in the brain as a result of being exposed to and successfully coping with stress.
So am I telling you to let your child play in traffic, throw him out into the wilderness to hunt for food, or to force him to participate in a plethora of undesirable after school activities? No. It doesn't have to be that complicated, nor should it be that extreme. The key point in the article is that mild stress exposure resulted in positive changes in the brain, not torture or a series of near-death experiences.
Alternatively, for example, rather than hovering over your child to make sure little Johnny doesn't bully him, you should teach him how to handle bully situations, so when the time comes and he is bullied (and it happens to everyone at some point), he is able to have some strategies in place to deal with it himself. Or if he gets bullied and is unprepared for it, discuss it with him rationally. Explain to him how to handle it next time, rather than marching over to the offending child and letting loose on him. Now, I know it takes a lot of restraint not to lash out at someone who hurts your child, but encouraging him to cope with it successfully on his own will help him build the kind of resilience that will make him a confident adult, able to control his temper and act level-headed in conflict situations in the future. And don't we all want a world full of more rational, level-headed adults?
The take-home point is this: not all stress is bad. Even as children, being faced with challenging situations is a good thing. We learn to problem-solve, think for ourselves, and build resilience to protect us from harm in future unexpected events. As an added bonus, dealing with stress early on helps us to develop emotional stability as well. You can't buffer your child from every non-happy moment in his life, so at least take comfort in the fact that while he is suffering in the short term, he is enhancing his well-being in the long term.
And building character, too.