Our brains don’t mature until our 20s. Knowing that could change how you talk to young people.

David Servan-Schreiber | November 2008 issue

Ben, 18, borrows his father’s car to go on a trip with friends. At 2 a.m., he’s driving more than 100 mph (160 km/h) on a country lane, the music blaring, the white lines marking the road ahead looking just like a video game. Behind him in the back seat, the girls have fallen asleep, their heads leaning on their boyfriends’ shoulders. Speed, music, girls. Ben has a feeling of total control, a perfect moment. Then comes a tight bend he wasn’t expecting. The car goes straight on, plunges over a ditch and smashes into a tree. It’s a miracle no one’s hurt. Ben’s father, Henry, can’t believe it. How on earth could Ben have taken such an appalling risk?
A taste for risk, a search for the rush of adrenalin, an inability to feel any motivation about the important things in life, an unquestioning following of the group, bouts of rage. What’s actually going on in an adolescent’s mind? A new generation of neuroscientists is asking exactly this question: Is a teenager’s brain the same as an adult’s? The surprising answer is, Absolutely not.
Since the work of child psychologist Jean Piaget, we’ve thought the development of the brain and its associated functions were complete at about 12 years of age. It’s true that by this time the brain has grown to full size. Improved brain-imaging techniques have proven, however, that the brain doesn’t reach maturity until we’re 20 or even 25.
The prefrontal cortex, which gives us our domed foreheads and distinguishes us from the large apes, is responsible for controlling our impulses and for our ability to project ourselves into the future. However, according to Jay Giedd of the National Institute of Mental Health in Bethesda, Maryland, the cabling of the white matter sheathing the neurons that transmit brain impulses isn’t complete until we’re near 20.
On the other hand, ovaries and testicles become active at the onset of puberty. Hormones released into the system are soaked up by neurons, stimulating the need to assert oneself, be taken seriously, explore outside the limits of the family and test one’s role within the peer group. We can therefore see a lag between hormonal activity, which pushes children to take risks, and complete brain maturation, which allows them to think before they act. This surely helps ­explain why the two principal causes of death among adolescents are accident and suicide.
So how can we support our children through this delicate phase? To help them overcome their lack of self-control, we can guide them with structured activities (homework, meals, sports, television). We also need to be able to communicate with them about sensitive subjects: problems with friends, breaking up, sex, alcohol and drugs.
Yet that’s exactly what adolescents most resent—being constantly nagged by their parents, who go on and on about the same old things. They respond by sulking or subsiding into silence. We must therefore learn to listen to them before we talk to them. One study from the University of Illinois suggests the more adolescents feel listened to by their parents, the more receptive they are.
So let’s start with what’s bothering them, rather than what’s worrying us. And there’s no getting round the key ingredients in all our most important relationships in life: healthy doses of patience and love.