National Public Radio (NPR) reported recently on a very interesting study of babies. This research, performed by Elizabeth Conradt at Brown University, looked at a phenomena called baseline respiratory sinus arrhythmia. This in itself is a very interesting concept. What exactly is this? It is the difference between your heart rate when you inhale and when you exhale. It turns out that some people have a larger difference than others. Everyone has a different set point in terms of heart rate variability.
Babies that have a bigger difference tend to have greater abilities to focus on things in their environment. If you show them a new toy, they will really look at it and interact with it. Babies with low heart rate variability tend to lose interest more quickly.
So it’s better to have a baby with higher heart rate variability? It’s not that simple. Babies with a higher set point of heart rate variability are more irritable and fussy particularly when their environment is changing. On the other hand, babies with a lower set point tend to be less fussy.
Heart rate variability turns out to be a pretty good predictor of how sensitive babies are to their environment, both in good and bad ways.
Anyway, Conradt’s research looked at mothers and babies who were living in poverty. They were interested in predicting how the children would do as they aged.
So first, at five months of age, they measured heart rate variability while the babies were listening to soothing music and watching soothing video.
Roughly a year later, when the babies were around 17 months old, they came back to the lab. At this point they measured two things. First the researchers evaluated behavioral problems such as anxiety or aggression. Then they performed an interesting test that measures the quality of attachment between a mother and the baby. The researchers took the mother and child to a strange room, where the toddler played for a bit. Then, without any warning, the mother got up and left the room. In most cases this will trigger the baby being upset and crying. This is typical and normal. The baby thinks, “Where did my mom go?!”
What the researchers were really interested in was what happened three or four minutes later when the mother returned. Could the mother quickly soothe the upset child, or did the toddler pull away from the mother and continue to be upset?
The researchers made the assumption that if the mother could easily soothe the toddler then it was a marker of good attachment and a secure environment.
So here’s the very interesting part of this research. How did the initial heart rate variability set point correlate with behavioral problems? It turns out that if the baby had a high set point and insecure attachment to their mother, then they had the worst behavioral problems. But if they had a high set point and secure attachments to their mothers, then they had the lowest incidence of behavioral problems.
Children with low set points fell in the middle of the range of behavioral problems, and were not affected by the quality of their attachment with their mothers.
The amazing finding was that the children who had high set points and good quality parenting as reflected by secure attachments to their mothers tended to have less behavioral problems even than babies in middle-class and affluent families!
This is fascinating research. It shows the influence of both nature and nurture. And it shows how a biological trait such as heart rate variability can either lead to good or bad outcomes in life based on the quality of parenting. Mostly though, it demonstrates how crucial good parenting is to later outcomes in life. Good parenting can create successful, well-balanced children even in circumstances of poverty. In fact, the study showed that for the more sensitive children, good parenting in poverty trumps bad or mediocre parenting in affluence!!!
Dr. Andrew Gottlieb is a clinical psychologist in Palo Alto, California. Dr. Gottlieb specializes in treating anxiety, depression, relationship problems, and other difficulties using evidence-based cognitive behavioral therapy (CBT). CBT is a modern no-drug therapy approach that is targeted, skill-based, and proven effective by many research studies. Visit his website at CambridgeTherapy.com or watch Dr. Gottlieb on YouTube. He can be reached by phone at (650) 324-2666 and email at: Dr. Gottlieb Email.