"Are you even paying attention?"
It's a question that frustrated parents frequently ask their busy kids, and the honest response is almost always "No."
It's difficult to blame them. According to new research on teenage brains, our relationship to specific sounds changes with time, making our mother's speech feel less meaningful.
Children aged 12 and younger had an explosive neuronal reaction to their mother's voice when their brains were scanned, activating reward and emotion-processing areas.
A transformation happens around a child's thirteenth birthday.
The neurological response to the mother's voice has changed. Instead, regardless of gender, a teenager's brain appears to be more receptive to all sounds in general, whether new or remembered.
The changes are so noticeable that researchers were able to estimate a child's age based on how their brain reacted to their mother's speech.
"Just as a newborn learns to recognize her mother's voice, a teenager learns to recognize fresh sounds," says Stanford University psychiatrist Daniel Abrams.
"You don't realize you're doing it as an adolescent. You're just being yourself: you have pals and new acquaintances with whom you wish to spend time. Your mind is becoming increasingly sensitive to and drawn to these strange sounds."
Researchers believe this is a marker of the growing social abilities of the adolescent brain. In other words, a kid does not wall off their family on purpose; their brain is simply evolving in a healthy manner.
Numerous lines of evidence demonstrate that a mother's voice has an influence on a child's health and development, including stress levels, social bonding, feeding abilities, and speech processing.
So it seems logical that a child's brain would be particularly sensitive to their parent's speech.
However, there comes a moment when it is more beneficial to listen to someone other than your mother.
"When teenagers appear to be rebelling by not listening to their parents, it's because they're programmed to pay greater attention to voices outside their house," explains Stanford University neuroscientist Vinod Menon.
The findings build on fMRI findings from the same team of researchers published in 2016, which indicated that children under the age of 12 had brain circuits that are selectively activated by their mother's voice.
However, when the study was expanded to include 22 teens aged 13 to 16.5 years old, the influence of a mother's voice was not as strong.
Instead, all voices heard by teens triggered auditory processing brain regions, allowing them to select out important information and establish social memories.
The subjects' brain scans showed less activation in reward areas of the brain when they were given a tape of their mother's voice speaking three nonsensical phrases vs a stranger's voice saying the same thing.
The ventromedial prefrontal cortex, the area of the brain that helps select whether social information is most useful, was similarly affected.
Researchers hope to learn more about how these brain circuits differ in people with neurological disorders.
Researchers at Stanford discovered that children with autism had a weaker reaction to their mother's voice than normal children. Understanding the underlying brain pathways may aid our understanding of social development.
The new study's findings are the first to demonstrate that as we become older, our hearing shifts away from our mother and toward a wider range of voices.
Other behavioral and neurological research back up this theory, indicating that reward regions in the teenage brain are characterised by heightened sensitivity to novelty in general.
These modifications might be important components of good social development, helping youngsters to get a greater understanding of others' perspectives and intentions.
"A kid must become autonomous at some time," Menon says, "and this must be driven by an underlying biological signal."