“Clean up your room now!” But two days later, my son’s bedroom is still one big pigsty. Recognizable scene? Researchers now know why adolescents don’t listen.

Scientists at Stanford University have discovered that the brains of 13-year-olds start to work differently. While young children are still attentive to their mother’s voice, adolescents are more receptive to new voices. In fact, MRI scans show that the reward center is more likely to be stimulated by unfamiliar voices than by their own mother’s voice. This may have a biological cause. Adolescents become more separated from their parents this way.

“We notice that children become more independent at some point,” said lead author Vinon Menon. “This process is accelerated by an underlying biological signal. We have now discovered this signal. It makes it easier for teens to make connections with people outside their own families. This helps them to explore the world.”

More activity in the brain

Researchers used results from a previous study and added data from teenagers aged 13 to 16.5 years† The scientists recorded mothers’ voices and later played them back, along with other people’s voices and non-social sounds (eg, the sound of a dishwasher). Scientists used an MRI scanner to properly study the brains of children. For example, they saw different brain areas light up when the different sounds were played.

What distinguished teens from younger children was that unfamiliar voices elicited more activity in the reward processing system’s so-called nucleus accumbens. This brain region plays an important role in positive experiences such as desire, motivation, passion and satisfaction. This area of ​​the brain also plays a role in falling in love. In addition, scientists saw more activity in the ventromedial prefrontal cortex, an area involved in assigning value to social information. This switch happens when kids are 13 or 14 years old and there is no difference between boys and girls.

The power of the mom’s voice

Over the past decade, scientists have learned more about the unique power of a mother’s voice. For example, a 2010 study found that oxytocin is released when a daughter hears her mother’s voice. Special, because for the time being it was assumed that a touch or hug was necessary. In 2016, scientists discovered that children identify their mother’s voice with a high degree of certainty†

“Mother’s voice is the sound source that teaches young children all about the social-emotional world and language development,” said co-lead author Percy Mistry. “Fetuses can recognize their mother’s voice before they are born, while adolescents – who have spent more time with their mothers than babies – tune their brains to voices they’ve never heard before.”

The research shows that major changes are taking place in the brains of teenagers. “Our findings show that this process is rooted in neurobiological changes,” Menon continues. “If teens go against their parents or don’t listen, it’s because they pay more attention to voices outside the family.”