Just what mothers need: one more thing to feel guilty about. A new study found that girls whose mothers were stressed during their daughters’ infancy grew up to experience more anxiety than others.
The preliminary findings of the study, published in Nature Neuroscience, are that “an early stressful environment during a baby girl’s first year was associated with altered brain behavior and signs of anxiety in her late teens.”
Scientists already had an inkling about the connection between the conditions of infancy and later behavior from studies of animals. Those experiments “pointed out how tough times in childhood influence the brain and the animals’ behavior later in life.”
One notorious example is Harry Harlow’s infamous experiments separating infant monkeys from their mothers. He isolated each baby with monkey mannequins.
The infants grew into deeply maladjusted adults. “Some sat clutching themselves, rocking constantly back and forth: a stereotypical behavior pattern for excessive and misdirected aggression.” The females who gave birth “were either negligent or abusive,” sometimes even killing their offspring.
One drawback of experimenting on animals like monkeys, besides the horrifying treatment of those infants, is that they are raised by mothers alone. Experiments like these help feed the popular stereotype that anything that is wrong with a child is the mother’s fault. This new study of humans, sadly, is in the same vein — as though fathers and other caregivers don’t have a role in forming an infant’s environment and experiences.
And what do you know — this lopsided study yielded strangely lopsided results: boys did not show any effect from stress during their first year of life, in contrast to girls.
The study went like this: “three times during the first year of their babies’ lives, the mothers reported whether they were experiencing stressful situations such as depression, marital conflict, money woes or parenting stress.” Researchers “assumed” that women experiencing stress created stress for their babies.
Scientists next checked in when the children were five and a half. They found that “daughters whose moms reported higher levels of stress had more of the stress hormone cortisol in their blood.” Boys’ cortisol levels were normal.
Fourteen years after that the women who had high cortisol as children had abnormal brain scans. “The behavior of two brain regions involved in regulating emotions — the prefrontal cortex and the amygdala — were out of sync.” As a result, they had trouble “shutting down negative emotions” and were more likely “to have problems with anxiety.”
The study doesn’t prove that mothers’ behavior caused their daughters’ anxiety. It only demonstrates a correlation between the mothers’ own self-reported anxiety levels and those of their daughters. It seems to me that mothers whose neurology made them more prone to anxiety would report more of it, and might pass on the genes for it. Or the study could be fatally flawed, or an aberration.
Or perhaps mothers really are magic and have complete power over their children’s lives, even after they are grown. Now that is something to feel anxious about.
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