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It’s been a bad day. Nothing dramatic, just one of those days where everything goes slightly wrong. You could send a quick message, but instead you find yourself scrolling to “Mom” and pressing call.
A few minutes later, you feel better, even though she hasn’t solved anything. Research suggests there may be a biological reason for that, and it has more to do with the sound of her voice than with anything she actually says.
A stressful test, then a call home
In 2010, biological anthropologist Leslie Seltzer and colleagues at the University of Wisconsin–Madison set up an experiment with girls aged 7 to 12. Each girl had to give an impromptu speech and solve math problems in front of strangers, a task designed to reliably cause stress.
Afterward, the girls were split into groups. Some were comforted by their mothers in person, with hugs and physical affection. Others spoke to their mothers on the phone. A third group watched a neutral film with no contact at all.
The researchers measured two hormones. One was cortisol, a marker of stress, in saliva. The other was oxytocin, a hormone linked to bonding and trust, in urine.
The phone worked almost as well as a hug
The results surprised the team. Girls who were hugged and comforted in person showed a rise in oxytocin and a drop in cortisol, as expected. But girls who only heard their mother’s voice on the phone showed a very similar hormonal pattern.
Physical touch has long been seen as a key part of comfort. This study suggested that a mother’s voice alone could do much of the same work, at least in the short term.
That left an obvious question. Was it the voice itself, or simply the comforting words? If it was the words, a written message should work too.
Then came the text test
In a follow-up study published in 2012, Seltzer’s team tested 68 girls aged 7.5 to 12 using the same stressful task. This time, one group could message their mothers by instant messenger after the test, while others spoke to them in person or by phone, or had no contact.
The mothers were asked to offer as much emotional support as they could. But the girls who messaged with their mothers showed no oxytocin response. Their cortisol levels were as high as those of girls who had no contact with their mothers at all.
The researchers concluded that the comforting effect seemed to come from hearing the voice, its tone, rhythm and warmth, rather than from the words themselves. One caveat they noted is that some mothers weren’t comfortable with instant messaging, and that clumsiness might have added to their daughters’ stress.
What happens in the brain
The hormonal changes in these studies trace back to the body’s stress system, the HPA axis. When we’re under pressure, this system triggers the release of cortisol. Oxytocin, made in the hypothalamus, is thought to help dampen that stress response.
Brain imaging research helps explain why a mother’s voice might be so powerful. In 2016, Daniel Abrams, Vinod Menon and colleagues at Stanford scanned the brains of children aged 7 to 12 while they listened to short clips of their mother’s voice and unfamiliar voices. A mother’s voice activated far more than hearing areas. It also lit up reward regions, emotion-processing areas such as the amygdala, and parts of the brain involved in recognizing faces and social information. Children could identify their mother’s voice from less than a second of audio.
The teenage switch
There’s a twist. In a 2022 follow-up, the Stanford team scanned 46 young people aged 7 to 16. In older adolescents, the pattern reversed. Unfamiliar voices produced more activity than their mother’s voice in the nucleus accumbens, a key part of the reward system, and in a brain region that helps assign value to social information.
The researchers think this shift helps teenagers turn their attention toward friends and the wider world, which they need to do to grow up. As Abrams put it, it’s not personal, just a natural part of development.
What this means for adults
None of these studies looked at adults, so we can’t say exactly how a mother’s voice affects a grown person’s stress hormones. Adult relationships with parents also vary widely, and for some people, a call home is more stressful than soothing.
But the research points to something many people already sense. Hearing a trusted loved one’s voice seems to reach the brain in ways a text message doesn’t. The teenage drift away from mom’s voice may not be the end of the story either. Many adults find themselves calling home again during hard times.
If that’s you, it isn’t a step backward. It may be your brain reaching for a source of comfort it learned very early in life, and the same may hold for a partner, a close friend or anyone whose voice you trust.
