Shhh, The Kids Can Hear You Arguing (Even When They're Asleep)

Apr 29, 2013
Originally published on April 29, 2013 8:17 pm

For years now, psychologists have been telling couples who yell at one another to stop for the sake of the kids. Such conflict in the home — even when no violence is involved — is associated with a host of negative behavioral and life outcomes for children.

Some strands of research have gone so far as to suggest that dissolving a marriage might be better for kids than exposing them to high levels of conflict within a bad marriage.

Still, the effects of parental conflict do not appear to be experienced equally by all children. Some kids do badly when exposed to conflict; others seem to cope much better. Recently, researchers at the University of Oregon decided to try to get a handle on this variability: Is it possible, they asked, that experiences early in life might sculpt the brain in ways that shape the child's response to conflict later in life?

Psychologists Alice Graham, Philip Fisher and Jennifer Pfeifer decided to take a look at what happens inside the brains of infants when they hear conflict and angry voices. The approach was straightforward: Use a noninvasive brain-scanning technique known as fMRI to scan the brains of infants and identify, in real time, which areas of the brain are activated by angry voices.

There was one problem. These brain scans required the infants to lie really still for an extended period of time in a noisy scanner. The odds of that happening: close to zero.

That is, unless, the psychologists reasoned, the infants were asleep. Was it possible that even during sleep, the brain continued to take in and process angry voices?

In a study published in Psychological Science that is at least as remarkable for its methodology as for its results, the researchers had a couple of dozen infants brought into a brain-scanning lab at bedtime. First, the parents rocked the infants to sleep. Then Graham and her colleagues carefully placed the sleeping children inside the brain scanner. Via a pair of headphones, they piped in voices saying nonsense sentences such as, "I pulimented a mopar." The voices spoke in different tones — angry, neutral and happy.

Graham, a doctoral student at the school, said the most surprising thing was not that the brains of infants responded differently to the different tones — which suggests that the brain is more than capable of taking in information while a child is asleep — but that there were stark differences among the children. Infants who came from homes with lots of conflict, where the parents yelled at one another and called each other unpleasant names, showed a heightened activation in certain areas of the brain.

"What we see for the infants in higher-conflict homes is that they are showing greater reactivity to the very angry tone of voice," Graham says, "and that reactivity is in brain regions that we think are important later on in terms of your ability to regulate your emotions and function well."

The scientists acknowledged that it's not immediately clear what the findings mean. If the infants from high-conflict homes are especially reactive to angry voices, this could be consistent with the studies that have found that conflict in the homes is psychologically damaging for children. On the other hand, it's also possible that the heightened activation is connected with the way the brain develops resilience: The brain activation might point to the possibility that the infants were learning to deal with high conflict. The only way to find out would be to follow such children over time and see what happens to them. Graham says the study is just a first step toward understanding the role of early influences in how children come to process conflict.

And as for advice to quarreling parents, she says, the bottom line might be simple: Your kids are listening to you, even when they are asleep.

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This is MORNING EDITION from NPR News. I'm Renee Montagne.


And I'm Steve Inskeep, good morning.

Today in Your Health, we have two stories about angry parents and how their arguments affect their children. We've known for a long time that when parents fight a lot, it can have a psychological impact on kids. In fact, some parents know this so well that they save their arguments until after they put the kids to bed. This morning we start with some disturbing new research on how arguments by parents affect infants.

NPR science correspondent Shankar Vedantam is here to tell us about it. Hi, Shankar.


INSKEEP: OK, so what is this new research telling us that was not known before?

VEDANTAM: Well, so lots of studies have looked at the link between parental conflict and outcomes in children. And most of them have looked at children who are older. And what researchers find is that there is a lot of variability. So some children seem to react really adversely to their parents' fighting. And other children seem largely fine.

INSKEEP: Some kids act out and become angry themselves. Some kids may just find a way to deal with it.

VEDANTAM: Yeah. So researchers have been asking what explains this variability among children. And one of the theories that they're exploring is that your experiences very early in life might sculpt the way you respond to conflict the rest of your life.

INSKEEP: Well, now this is real interesting, because we're talking about kids who obviously haven't learned to speak yet. They don't really know what's going on. They can't necessarily follow the argument, but they're asking does it affect the kid anyway.

VEDANTAM: Exactly, so researchers at the University of Oregon decided to conduct brain scans on a couple dozen infants. And it's a completely noninvasive procedure but you have to lie really still in the scanner. Now, obviously these are children who are six months to a year old; you can't expect them to lie still in the scanner, especially because it makes this really loud din.

And so, the researchers said: What if the children were asleep, is it possible that they're still taking in information even when they're asleep. And we can test to see how their brains respond to different kinds of conflict. So Alice Graham, Phil Fisher and Jennifer Pfeifer, they had parents bring in a whole bunch of babies at bedtime. And when the children were asleep they put the infants into the scanner, stuck headphones on them and played these different sentences.

And these weren't actual words and actual sentences. But these were nonsense sentences in different tones of voice. Some of them were angry and some of them were neutral and some of them were happy. I asked her what these sounded like and here's what she told me.

ALICE GRAHAM: So, maybe very angry would be like: I pulamented a mopar(ph). And just angry would be: I pulamented a mopar. And then in a neutral tone of voice it might be: I pulamented a mopar. And then in a happy tone of voice it might be: I pulamented a mopar.

INSKEEP: Now I'm thinking about all the different ways I can say that nonsense phrase. I pulamented a mopar? I pulamented a mopar. So what, Shankar, did the researchers find when they played these syllables to kids in different ways?

VEDANTAM: So, Graham told me she was astonished to find that the babies' brains actually reacted differently to the happy and the angry tones, that she could actually detect differences in brain reactions to these different tones. And what this shows is that even when children are asleep they are still taking in information. And that was not the most interesting thing.

She found that the babies who came from high-conflict homes - these are homes were the parents are shouting at one another, yelling at one another, calling each other names - these babies not only had even higher activation in the brain in response to angry tones, the activation was in specific areas of the brain linked to emotional functioning.

Here she is again.

GRAHAM: What we see for the infants in higher conflict homes is that they're showing greater reactivity to the very angry tone of voice. And that reactivity is in brain regions that we think are important later on in terms of your ability to regulate your emotions and function well.

INSKEEP: That's Alice Graham, who spoke with Shankar Vedantam. And, Shankar, I want to make sure I understand this. You're saying these are kids who have already, as infants, witnessed a lot of fighting. And when these angry sounds are played to them, you see their brains responding differently than other children. They seem to have been changed already by the experience of witnessing this fighting.

VEDANTAM: Yes. So the big question, Steve, is what do the changes in the brain actually mean. One possible interpretation is that these children are somehow already being scarred for life, and that they're going to respond to conflict in these heightened ways. Another interpretation could be this is how the brain learns to be resilient. And by adapting and changing you actually are going to reduce your reactivity to conflict later in life.

So I don't think we know exactly what it means that you're seeing these brain changes. But I think what we can say for sure is that what the study shows is that parents need to be aware that children are listening to what they say, even when they're asleep.

INSKEEP: That's NPR's science correspondent Shankar Vedantam. Shankar, thanks for coming by.

VEDANTAM: Thanks, Steve. Transcript provided by NPR, Copyright NPR.