Researchers map converging trajectories of cognitive development through adolescence
MINNEAPOLIS/ST. PAUL (11/16/2023) — A new study published in Nature Communications presents some of the first definitive evidence that executive function—a set of cognitive skills underlying the ability to plan, seamlessly switch from task to task, resist tempting distractions and focus on a task at hand—usually matures by the time an individual turns 18 years old.
The study collected and analyzed nearly two dozen laboratory measures of executive functions across four unique datasets, presenting a first-of-its-kind large scale chart of cognitive development in teens.
“In our study, we wanted to present a consensus and not just a hunch,” said lead author Brenden Tervo-Clemmens, PhD, an assistant professor at the University of Minnesota Medical School and Masonic Institute for the Developing Brain. “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.”
Unlike the meticulously mapped out milestones of childhood, the timeline of adolescence remained less formally defined, primarily due to the complexity of developmental processes set into motion with the onset of puberty. High variability among individuals and a lack of tools for analyzing complex datasets also limited the confidence of previous attempts to build a roadmap of brain development in teens.
The research team collected 23 distinct measures of executive function from over 10,000 participants from 8 to 35 years old. Scientists then analyzed those metrics by tracking their change over time and checking whether performance across different tests fit a single trajectory that could be described with a mathematical model.
The resulting analysis showed a common dynamic of executive function maturation that was shared between both sexes: a rapid burst of executive function development in late childhood to mid-adolescence (10-15 years old), followed by small but significant changes through mid-adolescence (15-18) that stabilized to adult-level performance by late adolescence (18-20). The findings have significant implications not only for psychiatrists and neuroscientists, but also for parents, educators and potentially the judicial system in defining the boundaries of the adolescent period.
“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, PhD, professor of psychiatry at the University of Pittsburgh School of Medicine. “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.”
By presenting reproducible growth charts across tasks and datasets, this roadmap could allow researchers to track how therapeutic and drug interventions might affect developmental milestones. For instance, adolescence is the time when many mental illnesses, which also have problems in executive function, such as schizophrenia, emerge. Charting the neurotypical brain development timeline will then allow researchers to better track any subtle shifts from the “norm” and possibly improve early diagnosis.
"I look forward to continuing this work at the University of Minnesota and the Masonic Institute for the Developing Brain so we can discover more about mental health disorders that first emerge during this period of adolescence and are linked to executive function," said Dr. Tervo-Clemmens. "This work will lay the foundation towards developmentally informed mental health treatments."
The study was done in collaboration with researchers from the University of Pittsburgh School of Medicine. This research was supported by the National Institutes of Health [grants R03MH113090 and R01MH067924] and the Staunton Farm Foundation.
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