Is Your 18-Year-Old Really ‘Mature’? New Brain Study Has Answers

An adolescent starts thinking like an adult right around the age of 18, according to new research.

That provides some of the first definitive evidence that executive function matures by that time.

Executive function is a set of mental skills that include the ability to plan, switch between tasks, resist tempting distractions and focus.

For the study, researchers collected and analyzed nearly two dozen laboratory measures of executive functions in more than 10,000 people.

Researchers said their findings have significant implications for psychiatrists, neuroscientists, parents, educators and potentially the judicial system.

“When I talk with parents, a lot of them say, ‘There is no way that my 18-year-old is a fully formed adult!'” said senior author Beatriz Luna, a professor of psychiatry at the University of Pittsburgh School of Medicine and authority on neurocognitive development.

“Other important behavioral factors that complement executive function, such as the ability to control one’s own emotions, can change with age. The ability to use executive function reliably improves with age and, at least in a laboratory setting, matures by 18 years of age,” Luna said in a university news release.

While many childhood milestones are mapped out, that timeline of adolescence transitioning to adulthood is less formally defined, according to the study. Individuals differ greatly. Analytical tools are limited.

“In our study, we wanted to present a consensus and not just a hunch,” said lead author Brenden Tervo-Clemmens, an assistant professor of psychiatry and behavioral sciences at the University of Minnesota.

“This is developmental science meets big data. We are using tools that were not available to researchers studying cognitive and brain development until several years ago. A study of this scale was made possible only by open data-sharing and collaborators who graciously gave access to their datasets without asking anything in return,” he said in the release. Tervo-Clemmens began this research as a graduate student in Luna’s lab at Pitt.

Using four unique datasets, the authors collected 23 distinct measures of executive function from 10,000 participants aged 8 to 35. They tracked changes over time and whether performance across different tests fit a single trajectory.

Researchers saw a rapid burst of executive function development from age 10 to 15. That was followed by small but significant changes through mid-adolescence, ages 15 to 18. Development reached adult-level performance by ages 18 to 20.

This roadmap could allow researchers to track how therapeutic and drug interventions might affect developmental milestones, the authors said.

Many mental illnesses emerge during adolescence, for example.

By charting the neurotypical brain development timeline, researchers may be able to track subtle shifts and possibly improve early diagnosis.

Study findings were published Oct. 30 in the journal Nature Communications. The research was supported by the U.S. National Institutes of Health and the Staunton Farm Foundation.

More information

The U.S. National Institutes of Health has more on the teen brain.

SOURCE: University of Pittsburgh, news release, Oct. 31, 2023