Sep 7, 2026 · 14 min
Brain development keeps changing past the supposed age of maturity
When is your brain actually 'adult'?
The findings challenge a simple age-25 cutoff while showing why brain development varies across people and unfolds over a much longer timeline.
- 1Four broad turning points describe brain development from childhood through later adulthood.
- 2Long-range brain connectivity continues developing until around age 32, beyond the familiar age-25 milestone.
- 3MRI averages reveal broad patterns, not fixed timelines that determine individual behavior or mental health.
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Duncan Astle explains why the brain’s slow development may be a strength rather than a deficiency.
The brief
The familiar claim that the brain becomes fully mature at 25 rests on a misleadingly tidy cutoff. New research instead finds several broad turning points across the lifespan.
Neuroscientist Duncan Astle describes findings from 4,000 MRI scans: local connections develop early, while long-range connectivity keeps strengthening until about age 32.
The scans show population-level patterns, not identical timelines. Age ranges can describe how brains tend to change without predicting any one person’s behavior or abilities.
That distinction matters for adolescence, when impulsivity reflects both developing brain systems and changing social environments, and for mental health conditions that emerge at different phases.
Astle’s central takeaway is that unusually slow human brain development may be a strength, giving the species an extended period for learning and adaptation.
Featuring
Duncan AstleMentioned
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