From "Romeo and Juliet" to "Rebel without a Cause" to "Twilight," the intense and complicated emotions all of us experience during adolescence have been well documented. And since the teenage years correlate with the onset of sexual maturity, parents for years have written off teenage angst to the surge of hormones.
But neurologist Frances Jensen says “the emotionality that is usually tagged to the 'hormone effect'—the rage, the risk-taking behavior, this unpredictable behavior of teenagers" has more to do with a brain that hasn’t developed enough to handle the emotions those hormones trigger.
“The prefrontal cortex and frontal cortex, which control impulses and add reasoning, executive function and judgment, are not as developed at a time where the emotional area—the limbic system—is really quite mature, relative to the frontal lobe. And so we believe that a lot of that heightened emotionality, the risk-taking behavior is due to that mismatch.”
"Brain development goes on a lot longer than previously thought," Jensen says.
“A lot of us, in my generation, were taught in psychology classes, ‘Oh, you know, it’s done by 12,'" Jensen said. "And it’s not. We are now understanding that brain development is a long-term process, and actually the more obvious parts of brain development still don’t really complete until the mid- to late-20s.”
The teenage brain undergoes a process of rapidly paring down neurons, Jensen says—but intellectual development isn’t slowing. The opposite is happening, as connections between the neurons that remain are established and strengthened. And while we can learn new things and develop connections between neurons our entire lives—the teen years are the prime time for developing those connections, known as synapses.
Jensen told me that’s the reason why, when I was 15, I could memorize a poem in less time than it took me to understand what it meant.
“One of the properties of a young brain is the ability to adapt and strengthen synapses much faster than the adult," she said. "All of the molecular machinery that’s underneath the synapse that helps make it bigger is genetically programmed to be at higher levels in childhood and adolescence, so annoyingly, teenagers and children, certainly, can just learn things flawlessly.”
Think of the accomplishments of young Olympic athletes, musicians and math whizzes, and it’s not hard to get a sense of what this teenage brain can accomplish. But a brain that’s primed to be a learning machine is a two-edged sword—or as Jensen puts it, this “synaptic plasticity” is a mixed blessing. While a teenager might be great at memorizing a sonnet or learning Mandarin,they’re also great at learning destructive behaviors.
“Just as teenagers can learn things—their memories are harder, stronger, longer, faster—they can get addicted harder, stronger, longer, faster than adults,” she said.
This smart young brain is prone to making poor decisions—and when it does, it’s really good at learning to be bad.
“This part goes back to the synaptic plasticity, which, they have an edge, definitely, to learn and memorize things faster," Jensen said. "Their brain cells are responding to good things fast. But they are just as impressionable to 'bad things' which could be substances of abuse, and without that frontal lobe to say ‘don’t take that risk,’ kids are taking more risks, and actually their brains are more susceptible to addiction in this window than they will be later.”
So it’s really important that teenagers make good choices when it comes to high-risk behaviors. It might seem intimidating, but Jensen thinks it’s important young people know their intellectual destiny is in their own hands.
"A lot of people thought that your IQ was an inherent property that you could be labeled with at, you know, 9 or 10 years of age, and that was it," she said. "That was what you got for life. No! There’s an opportunity beyond that, and it’s best in the teenage window.”
But can knowing their brains work can help young people make better choices? Jensen thinks so—and Kirk Carapezza looked into what these new discoveries about the teenage brain could mean for higher education.
