Before they’re even born, babies tune into their mother’s voice and can distinguish it from unfamiliar female voices. By the time they are adolescents, though, kids begin to listen less to their mother’s voice and listen more to voices outside the family. It’s easy to take this personally, but new research reveals that it really has to do with changes in the teenage brain that accompany the other physical changes teens go through on their road to independence.

In a 2022 study published in the Journal of Neuroscience, researchers from Stanford University used functional magnetic resonance imaging (fMRI) to scan the brains of 46 children, aged 7 to 16, to obtain the first detailed neurobiological explanation for how teens begin to separate from their parents.  

Maternal vs. external voices

In response to listening to short samples of their mother’s voice and those of unfamiliar women, the researchers discovered a shift in brain activity associated with a wide range of auditory, cognitive and social evaluative processing systems, and especially the reward processing regions in their brain.

In their previous 2016 study, these researchers found that in the preadolescents, several different parts of the brain, including reward centers, light up when they hear their mother’s voice, but not the voice of a stranger. 

Yet this new research indicates that for kids around 13 years of age, regardless if they were boys or girls, their mother's voice no longer generated the same neurological reaction compared to the younger children. In fact, the opposite occurred—unfamiliar voices elicited greater activity than a mother’s voice in the reward-processing system and in the part of the brain that helps determine which social information is most valuable.

Related: It's science: Mama’s voice reduces pain in premature babies

Tuning out and tuning in 

It can be joyous but also challenging to watch your kids need you less as they grow older. 

Researchers think this switch to focusing on unfamiliar voices is part of the biological signal that drives teens to separate from their parents and towards connections outside of their family, enabling them to learn to socialize and understand better the perspectives and intentions of others they interact with. This newfound ability to assess their environments aligns with the changes in the brain associated with risk-taking and novelty—also hallmarks of teen behavior.

“Just as an infant knows to tune into her mother’s voice, an adolescent knows to tune into novel voices,” says lead author of the study Daniel Abrams, PhD, clinical associate professor of psychiatry and behavioral sciences at Stanford University School of Medicine, in a statement. “As a teen, you don’t know you’re doing this. You’re just being you: You’ve got your friends and new companions and you want to spend time with them. Your mind is increasingly sensitive to and attracted to these unfamiliar voices.” 

It's not personal. It’s just a natural part of development.

Babies and young children need to tune into mama to survive. But when kids hit their teens, their focus needs to turn outward as they prepare to become independent. 

The natural compulsion towards independence was also evident in the brain regions involved with filtering information and creating "social" memories as they became more active the older a teenager was. 

Indeed, the relationship was so strong, researchers could use the voice-response information in the teens’ brain scans to predict how old they were. 

Related: It's science: Mama's voice wakes kids up faster than an alarm

Music to their ears

“The fact that the brain is so attuned to voices makes intuitive sense,” says Dr. Abrams. “The voices in our environment are this incredibly rewarding sound source that allow us to feel connected, included, part of a community and part of a family. Voices are really what connect us.” 

Likewise, Dr. Abrams thinks the music that people in general listen to during this stage of development becomes so important and impactful in life. “It would be cool to try to understand how our minds and brains form such powerful associations with the music we hear during adolescence.”

Related: I'm a therapist and I didn't connect to my baby until I did this

Applications for autism research

The researchers are intrigued by these findings in how they might be applied to kids with autism.

Young children with autism appear to have a weaker brain response to their mothers’ voices than that of typically developing children. "Kids with autism often tune out from the voices around them, and we haven't known why," says Dr. Abrams. 

In studying what happens in the brains of adolescents with autism and other conditions that affect how they tune into voices and other social stimuli, researchers hope to understand more about the underlying neurobiological mechanisms of social development and how it can help scientists examine how these brain circuits differ among those with neurological conditions and social and communication difficulties. 

Although this research ultimately highlights how little is known about the dramatic changes that occur to the auditory system during adolescence, Dr. Abrams emphasizes that the 2022 study does not show that teens don't listen to their parents. "It just shows that the brain reward system shows a preference for unfamiliar voices compared to mother's voice during this stage of development," he tells Motherly. "Crucially, your adolescent child is definitely still listening to you, and they need your voice and guidance through all of the ups and downs of adolescence—so, please keep talking to them, no matter what.”

Sources

Abrams DA, Chen T, Odriozola P, Cheng KM, Baker AE, Padmanabhan A, Ryali S, Kochalka J, Feinstein C, Menon V. Neural Circuits Underlying Mother’s Voice Perception Predict Social Communication Abilities in Children. Proceedings of the National Academy of Sciences. 2016 May 31;113(22):6295-300. doi:10.1073/pnas.1602948113

Abrams DA, Padmanabhan A, Chen T, Odriozola P, Baker AE, Kochalka J, Phillips JM, Menon V. Impaired Voice Processing in Reward and Salience Circuits Predicts Social Communication in Children with Autism. Elife. 2019 Feb 26;8:e39906. doi:10.7554/eLife.39906

Abrams DA, Mistry PK, Baker AE, Padmanabhan A, Menon V. A Neurodevelopmental Shift in Reward Circuitry from Mother's to Nonfamilial Voices in Adolescence. Journal of Neuroscience. 2022 May 18;42(20):4164-73.

Blakemore S, Mills KL. The Social Brain in Adolescence. The Cognitive Neurosciences. 2014 Oct 24:33-40. 

Digitale E. The teen brain tunes in less to Mom’s voice, more to unfamiliar voices, study finds. News. Stanford Medicine  April 28, 2022 

Galvan A, Hare T, Voss H, Glover G, Casey BJ. Risk‐taking and the Adolescent Brain: Who Is at Risk?. Developmental science. 2007 Mar;10(2):F8-14. doi:0.1111/j.1467-7687.2006.00579.x

Leipold S, Abrams DA, Menon V. Mothers Adapt Their Voice During Children’s Adolescent Development. Scientific reports. 2022 Jan 19;12(1):1-0. doi:10.1038/s41598-022-04863-2

Will, GJ, Güroğlu B. (2016). A Neurocognitive Perspective on the Development of Social Decision-Making. InNeuroeconomics. 2016; 293-309. doi:10.1007/978-3-642-35923-1_15