What Scientists Saw in Kids’ MRIs While Hearing Moms’ Voices Will Amaze You

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Did you know that newborns prefer the sound of their mothers’ voices over the voices of other women?

Now, the first-ever study to look at brain scans of kids as they listened to moms’ voices shows just how important this connection may be.

A study by the Stanford School of Medicine recently published in the Proceedings of the National Academy of Sciences (PNAS) suggests the strength of the connections between brain regions activated by the voice of a child’s mother predicts that child’s social communication abilities.

Researchers looked at 24 children ranging in age from 7 to 12 — all of whom had IQs of at least 80, none of whom had developmental disorders and all of whom were being raised by their biological mothers. As part of the study, parents filled out a questionnaire about their child’s social skills, and then each mom was recorded saying three nonsense words prior to the brain scans. Additionally, two women who hadn’t ever met any of the children in the study were recorded saving these three nonsense words. (Researchers didn’t want to use words that had meaning because that would have engaged a different set of circuitry in the brain.)

Using magnetic resonance imaging (MRI,) researchers scanned the brains of the children as they listened to a mix (some of a Mom and some of the control women) of the nonsense-word recordings. Even from very short clips, kids could identify their own mothers’ voices with over 97-percent accuracy.  

What’s more is the network of brain regions engaged by voices of children’s mothers was larger than researchers predicted. They included auditory regions, like the primary auditory cortex; regions of the brain that handle emotions, like the amygdala; brain regions that detect and assign value to rewarding stimuli, like the mesolimbic reward pathway and medial prefrontal cortex; regions that process information about the self, including the default mode network; and areas involved in perceiving and processing the sight of faces.

Children whose brains showed a stronger degree of connection between all these regions when hearing their mom’s voice also had the strongest social communication ability. This suggests that increased brain connectivity between the regions is a neural fingerprint for greater social communication abilities in children.

“Voice is one of the most important social communication cues,” Menon said. “It’s exciting to see that the echo of one’s mother’s voice lives on in so many brain systems.”