Sleeping Babies Can Sense When Mommy and Daddy Are Fighting

The infant brain is even more impressionable than previously thought

The computing power of an infant's brain still astounds. Traci DaBerko

Opening a new window into the mysterious realm of how infants respond to their surroundings, researchers have found that parental bickering appears to have a visible effect on babies’ brains—even when the little ones are sleeping.

Previous studies suggest that frequent fighting at home, including spats several decibels lower than anything in Who’s Afraid of Virginia Woolf?, can set a child up for anxiety and behavioral problems, but psychologists at the University of Oregon wanted to learn how and when the stressful experience can leave its mark.

So they asked mothers, recruited through fliers and on Craigslist, to fill out a standard survey gauging how often tempers flare at home, and then examined the brain activity of their 6- to 12-month-old babies using functional MRI, a type of noninvasive imaging technology designed to detect blood flow in real time. That blood flow serves as a proxy for brain activity.

Each of the 24 infants was placed in the laboratory scanner after a parent had put him or her to sleep. The babies wore headphones that delivered recordings of nonsense phrases read in neutral and angry voices—and that protected tiny ears from the machine’s loud banging noise.

The brain scans turned up an intriguing difference, says Alice Graham, the graduate student who conducted the study. Babies whose parents often fought at home had a stronger neurological response to angry tones—as shown by the intensity of the colors in a computer-generated brain map—compared with babies from less conflict-ridden households. The strong brain activity was centered in regions associated with the processing of stress and emotion, the first time this pattern has been observed under these conditions.

Parental conflict, which can often occur after a newborn joins the family, appears to affect how young brains respond to stressful stimuli, say the researchers. But it is too soon to say whether there will be negative consequences later on. “It could be that this is adaptive,” Graham says, “that the way they’re responding in higher-conflict homes is helping them adjust to life in those homes.”

For now, psychologist Ben Hinnant of the Catholic University of America in Washington, D.C. urges parents to find constructive ways to resolve their disagreements. His own studies show that kids who are already sensitive to stress can experience a sort of burnout if their parents fight often, leading to later trouble handling frustration. “What you’re doing in front of your kids, how you’re talking to your spouse, has a big effect,” Hinnant says.

The new research underscores the view that little brains are incredibly impressionable. Even saving an argument for nap time may not spare a baby. “There isn’t really time off from being a parent,” says Graham.

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