Summary: At 13, teens no longer find their mother’s voice particularly gratifying and listen more to unfamiliar voices. A new study reveals the neurobiology that explains why adolescents begin to separate from their parents at this developmental stage and how this shapes them to become more socially adept outside of a family setting.
When your teens can’t seem to hear you, it’s not just that they don’t want to clean up their room or finish their homework: their brains aren’t registering your voice like they did before they were teenagers.
By age 13, children’s brains no longer find their mother’s voice particularly gratifying and they’re more attuned to unfamiliar voices, according to a new study from the Stanford School of Medicine.
The research, which was published April 28 in the Journal of Neuroscienceused functional brain MRIs to provide the first detailed neurobiological explanation of how adolescents begin to separate from their parents.
“Just as an infant knows how to tune in to their mother’s voice, an adolescent knows how to tune in to new voices,” said study lead author Daniel Abrams, PhD, clinical associate professor of psychiatry and science. behavior.
“As a teenager you don’t know you’re doing this. You are just you: you have your friends and new companions and you want to spend time with them. Your mind is increasingly sensitive and attracted to these unknown voices.
In some ways, the teenage brain is more receptive to everything voices — including those of their mothers — than the brains of children under 12, the researchers found, a finding that aligns with teens’ heightened interest in many types of social cues.
However, in adolescent brains, the reward circuits and brain centers that prioritize important stimuli are activated more by unfamiliar voices than by those of their mothers. The evolution of the brain to new voices is one aspect of healthy maturation, the researchers said.
“A child becomes independent at some point, and that must be precipitated by an underlying biological signal,” said study lead author Vinod Menon, PhD, Rachael L., and Walter F. Nichols, MD. , Professor and Professor of Psychiatry and Behavioral Sciences.
“That’s what we found: It’s a cue that helps teens engage with the world and make connections that allow them to be socially adept outside of their families.”
Age-related change to new voices
The Stanford team previously found that in the brains of children 12 and under, hearing mom’s voice triggers an explosion of unique responses: study published in 2016 showed that children can identify their mother’s voice with extremely high accuracy, and that Mom’s special sound signals not only auditory processing areas of the brain, but also many areas not triggered by unfamiliar voices, including reward centers, emotion processing regions, visual processing centers and brain networks that decide what incoming information is salient.
“The mother’s voice is the sound source that teaches young children about the whole social-emotional world and language development,” said Percy Mistry, PhD, co-lead author and researcher in psychiatry and behavioral sciences.
“Fetuses in utero can recognize their mother’s voice before they are born, but in adolescents – even though they have spent even more time with this sound source than babies – their brains drift away from it in favor of voices that they never heard.
The new study builds on the previous study, adding data from adolescents aged 13 to 16.5. All participants had an IQ of at least 80 and were raised by their biological mother. They had no neurological, psychiatric or learning disabilities.
The researchers recorded the teens’ mothers saying three nonsense words, which lasted just under a second. The use of nonsense words ensured that participants would not react to the meaning or emotional content of the words. Two women who did not know the study subjects were recorded saying the same nonsense words.
Each participating teenage girl listened to multiple repetitions of nonsense-word recordings by her own mother and unknown women, presented in random order, and identified when she heard her mother. Just like younger children, teenagers correctly identified their mother’s voice more than 97% of the time.
The teenagers were then placed in a magnetic resonance imaging scanner, where they played back the voice recordings. They also listened to brief recordings of household sounds, such as a running dishwasher, to allow the researchers to see how the brain responds to voices compared to other non-social sounds.
More activation overall
The researchers found that in adolescents, all voices elicited greater activation in several brain regions compared to younger children: the voice-selective superior temporal sulcus, an area of auditory processing; salience processing regions that filter important information; and the posterior cingulate cortex, which is involved in aspects of autobiographical and social memory.
Brain responses to voices increased with adolescent age – in fact, the relationship was so strong that researchers could use voice response information in adolescent brain scans to predict their age.
What distinguished adolescents from younger children was that unfamiliar voices elicited greater activity than mom’s voice in the nucleus accumbens of the reward processing system and in the ventromedial prefrontal cortex, a region involved in value attribution. to social information. The shift to unfamiliar voices occurred in these brain centers between the ages of 13 and 14, and there was no difference between boys and girls.
The research will help study what happens in the brains of adolescents with autism and other conditions that affect how they attune to voice and other social stimuli. Young children with autism don’t have as strong a brain response to their mother’s voice as typically developing children, the Stanford team found.
The team is thrilled to have uncovered the foundations of teens’ ability to connect to new people, an important part of overall human engagement with voices. That the brain is so sensitive to voices makes intuitive sense – just ask anyone who has ever felt an emotional jolt hearing the voice of a friend or family member after a long time, said Researchers.
“The voices in our environment are this incredibly nurturing source of sound that makes us feel connected, included, part of a community and part of a family,” Abrams said. “The voices are really what connects us.”
Children’s social interactions undergo a major transformation during adolescence. “Our results demonstrate that this process is rooted in neurobiological changes,” Menon said. “When teens seem to rebel by not listening to their parents, it’s because they’re wired to pay more attention to voices outside their homes.”
The other authors of the Stanford paper are former research assistant Amanda Baker and former research scientist Aarthi Padmanabhan, PhD.
The study authors are members of the Stanford Wu Tsai Neurosciences Institute, Stanford Bio-X and the Stanford Maternal and Child Health Research Institute.
Funding: The study was funded by the National Institutes of Health (K01 grants MH102428, DC011095, MH084164, DC017950, and DC017950-S1), the Brain and Behavior Research Foundation, the Singer Foundation, and the Simons Foundation/SFARI.
Stanford’s Department of Psychiatry and Behavioral Sciences also supported the work.
About this neurodevelopment research news
Author: Erin Digital
Contact: Erin Digital – Stanford
Picture: Image is credited to Stanford
Original research: Access closed.
“A neurodevelopmental shift in reward circuitry from maternal to non-familial voices in adolescenceby Daniel A. Abrams [Ph.D.]Percy K. Mistry [Ph.D.]Amanda E. Baker [M.A.]Aarthi Padmanabhan [Ph.D.] and Vinod Menon [Ph.D.]. Journal of Neuroscience
A neurodevelopmental shift in reward circuitry from maternal to non-familial voices in adolescence
The social world of young children primarily revolves around parents and caregivers, who play a key role in guiding children’s social and cognitive development. However, a hallmark of adolescence is a shift in orientation toward non-familial social targets, a process of adaptation that prepares adolescents for independence. Little is known about the neurobiological signatures underlying adolescent social orientation changes.
Using functional brain imaging of human voice processing in children and adolescents (ages 7-16), we demonstrate distinct neural signatures for maternal voice and non-familial voices throughout development. of the child and adolescent in the reward and social evaluation systems, instantiated in the nucleus accumbens and the ventromedial prefrontal cortex.
While younger children showed increased activity in these brain systems for the mother’s voice compared to non-family voices, older adolescents showed the opposite effect with increased activity for the non-family voice compared to the voice of the mother.
The results reveal a critical role for brain reward and social valorization systems in pronounced changes in adolescent orientation toward non-familial social targets.
Our approach provides a model for examining developmental changes in social reward and motivation in people with pronounced social impairments, including adolescents with autism.
Children’s social worlds undergo transformation during adolescence. While socialization in young children revolves around parents and guardians, adolescence is characterized by a shift in social orientation towards non-familial social partners.
Here, we show that this change is reflected in measured neural activity from reward processing regions in response to brief speech samples.
When young children hear their mother’s voice, reward processing regions show greater activity than when they hear unfamiliar and unfamiliar voices.
Strikingly, older adolescents show the opposite effect, with increased activity for the non-family voice relative to the mother’s voice.
The findings identify the brain basis of adolescent social orientation shift toward non-familial social partners and provide a model for understanding neurodevelopment in clinical populations with social and communication difficulties.