This Is When Your Kid’s Brain Comes Online

A recent study that researchers referred to as “developmental science meets big data” appears to sharpen our understanding of cognitive development in adolescents. Published in Nature Communications, it offers some of the first definitive evidence that executive function — the set of cognitive skills that include working memory, self-control, and flexible thinking — typically matures by the time a person reaches their 18th birthday.

An encompassing concept, executive function is foundational for a person’s ability to handle multiple tasks simultaneously, plan ahead, resist distractions, and see a situation from another person’s perspective. But, as this research confirms, it’s not a skill set that flips on like a light switch — it’s more of a developmental slow burn that evolves over time, starting around eight years old.

“This study shows that executive function is a development of mastery,” lead author Brenden Tervo-Clemmens, Ph.D., assistant professor of psychiatry and behavioral sciences at the University of Minnesota, told Fatherly. “One of the things we were really trying to understand, especially at the beginning of the study, was the trajectory of the mathematical model that describes this sort of level of mastery.”

Researchers assembled an unprecedented large-scale chart of cognitive development in teens by collecting and analyzing nearly two dozen laboratory measures of executive functions in over 10,000 participants between the ages of 8 and 35 across four unique datasets. It was an undertaking that until recently was unachievable, as researchers lacked the tools to analyze complex datasets with high confidence.

A news release summarizing the study findings explained that in both sexes, executive function maturity happens in several stages, beginning with a rapid burst in late childhood to mid-adolescence. Small but significant changes continue to occur throughout the teenage years, with executive function stabilizing to adult-level performance between the ages of 18 and 20.

In other words, while teenagers often frustrate adults with hummingbird-like attention spans, brain maturation is largely complete far before age 25, as previously thought.

So, if kids typically develop executive functioning abilities in their teenage years, why does it seem so difficult to get them to turn homework assignments in on time or do chores without multiple reminders? It’s a common question.

“Parents will come to me and say, I don't understand why my teenager can't clean his room, but he can spend 12 hours playing video games and beating all these levels cooperatively with his friends,” Tervo-Clemmens says. “We know that preferred activities with a social and emotional pull are much easier to master. Adolescents will tend to perform better in emotionally rewarding or engaging activities.”

So, while executive function abilities may exist younger than previously assumed, there’s still an onus on parents, caregivers, and teachers to creatively add fun and social elements to otherwise mundane tasks. While the skillset exists underneath the surface, its application can be helped along in developmentally appropriate ways.

As previously reported by Fatherly, spacing out a series of rewards is a great way to help kids complete multi-step tasks that require executive functioning skills such as focus and sequencing. Motivation varies from kid to kid, but doing a favorite activity with a parent or the chance to pick out a favorite meal to cook at home are rewards that can fit easily into day-to-day life without breaking the bank.

Tervo-Clemmens also emphasizes that, since mastery is key to a robust understanding of executive functioning, parents should draw attention to times when kids when put forth effort even though it doesn’t result in a desired outcome. This is key to developing a growth mindset.

“If adolescents think hard about a decision, we should give them credit for that even if the decision they land on isn’t our preferred choice since they are learning how to master those skills,” he suggests.

Beyond insights into setting reasonable expectations for kids, Tervo-Clemmens points out that there are also mental health implications of the new research and analysis. Initial signs of mental health disorders, such as anxiety and depression, are typically tied to executive function and appear between the ages of 10 and 25 years old.

“That doesn't always mean that some individual patients will meet diagnostic criteria, but it's usually that they can be disambiguated from their peers that won't develop a mental health disorder,” he says. “So the idea is if we could have a normative growth chart for executive function, much like we have a height and weights for little kids, we might be able to chart deviations from normative development as a kind of an early warning sign for mental health disorders.”

Tervo-Clemmens also notes that he and other researchers are just scratching the surface. This first paper is just the beginning of a clearer understanding of adolescent brain development, and more work needs to be done outside of a lab setting to see how these insights hold up in the real world.

“The purpose of all this executive function development is to help adolescents explore their environment and become the adults that they're supposed to be,” Tervo-Clemmens says.