The teenage brain is a double-edged sword: sure, teens can be reckless and more susceptible to addictive behaviors than adults are, but those same brain pathways may also help them learn better than adults do, a new study suggests. So teachers and parents might just have to take the good with the bad if they want well-educated kids.
Take the good with the bad
Teenagers are especially sensitive to the reward signals that shoot through the brain after accomplishing something, getting approval from friends, taking drugs, and playing video games. This isn’t all bad. Chasing those feelings might make adolescents lose hours hunting for "likes" on social media. But it can also make taking risks and exploring unfamiliar experiences a lot more worthwhile. This could be a clue that the carrot is better than the stick for getting teens to learn new information.
Scientists have thought for a while that the teenage brain might not just be an immature version of the adult brain, but one that’s specifically primed to take in new information. Only, they didn’t have much proof. So researchers led by Daphna Shohamy, a cognitive neuroscientist at Columbia University’s Zuckerman Institute, set out to understand just how rewards affect learning. She challenged a small group of 41 teens aged 13 to 17 years old and 31 adults aged 20 to 30 to two different memory tests. The teens out-performed the adults on both tests and used a region of their brain involved in memory — called the hippocampus — that the adults didn’t. Shohamy and her colleagues published their findings in the journal Neuron this week.
"It’s welcome to see adolescent learning as different from adult learning, and in some circumstances, potentially superior," says Linda Wilbrecht, a psychologist at UC Berkeley who wasn’t involved in the research.
The test itself was pretty basic. The study participants were presented with two different flowers and a butterfly on a computer screen. They had to choose which flower the butterfly would land on. Each time they guessed, they’d get feedback: either "correct" or "incorrect" would appear on the screen, along with a picture of a random object like a pen, or a watermelon (more on this later). About 80 percent of the time, the same butterfly paired with the same flower — but the other 20 percent it didn’t, resulting in an "incorrect" answer.
The researchers measured how many "incorrects" it took for the test-takers to readjust their answers. It took the teenagers longer than the adults, which, counterintuitively, means they learned the higher probability set of rules better, the authors explain. Not everyone in the field interprets the slower learning rate as a better learning strategy, but the teens were also more accurate than the adults were. That gives a lot of support to the authors’ argument that it’s a better learning strategy, says Jee Hyun Kim, a developmental psychobiologist at the University of Melbourne who was not involved in this research, in an email to The Verge.
Specifically primed to take in new information
What’s more, the teens didn’t just seem to learn better than the adults — they also learned more information. Remember those random objects that flashed on the computer screen with the "correct" or "incorrect" feedback after each question? Those turned out to be part of a second memory test where the participants had to decide whether or not they’d seen them before. The teens were much better at recalling that they’d seen the pen or the watermelon, for example, than the adults were — especially when they’d seen the object paired with the positive "correct" feedback. The researchers assumed that "correct" feedback felt rewarding to the test-takers, although they didn’t confirm that the study subjects preferred the positive reinforcement. The idea, though, is that the reward helped encode more information than just what the teens learned about the butterflies and the flowers.
To figure out why the teens were better at this, the scientists used a neuroimaging technique called fMRI to watch areas of the brain where blood-oxygen levels rose during the test. It’s a non-invasive indicator of brain activity — but has to be taken with a grain of salt. After all, a few years ago an fMRI study showed a dead salmon had brain activity. (Dead things, as a rule, don’t.)
But Kim says that the paper’s methods looked sound. The scientists found more activity in the hippocampus of teens than in the adults. Teens also seemed to have more of a connection between increased activity in the hippocampus and increased activity in the brain’s reward center — called the striatum. That the hippocampus might be the source of these age differences is "very interesting and is quite novel," Kim says.
Shohamy cautions this is just one study. But the results could have some pretty interesting implications for education. Based on what this tells us about teenage brains, teachers and parents might want to be sure they’re giving teens prompt, constructive feedback. And rewarding teens for getting something right rather than punishing them when they don’t could be extra effective at helping them remember what they learned.
"If you’re someone who focuses on learning and memory, like we do in my lab, then you don’t think of reward-seeking as necessarily a bad thing. You think of rewards as something that shapes — and can have a really important role in shaping — learning," Shohamy says.