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When Do We Become Adults, Really?

Source: newyorker.com

TL;DR

Scientists debate when adulthood truly begins, challenging the legal age of 21 as too early for full brain maturity.
Brain scans show the prefrontal cortex, key for decision-making, develops into the mid-twenties.
Emerging adults face unique risks like addiction and recklessness due to this mismatch between biology and law.
Redefining adulthood could reshape policies on voting, drinking, and criminal responsibility.

The story at a glance

A New Yorker exploration probes the elusive boundary of adulthood amid rising questions about youthful impulsivity and legal maturity. It's timely as neuroscientists clash with policymakers over brain science's role in defining rights and responsibilities.

Key moments & milestones

1960s: Cultural shift births the "teenager," delaying adulthood markers like marriage and work.
1990s: Laurence Steinberg's research highlights adolescent brain immaturity, influencing U.S. Supreme Court rulings on juvenile sentencing.
2005: Court cites brain science to ban executing those under 18.
2012: Rulings extend protections to under-18s for life sentences without parole.
2020s: Studies push maturity timeline to 25, fueling debates on voting and drinking ages.

Signature highlights

The prefrontal cortex, governing impulse control and foresight, isn't fully wired until the mid-twenties, explaining why 20-year-olds rival teens in risky behaviors like drunk driving.
Laurence Steinberg's balloon analogue risk task shows teens and young adults take bigger risks when peers watch, a trait fading only by 22.
In Kenya, 25 marks adulthood culturally, aligning with biology - unlike the U.S., where 21 governs booze but 18 allows combat.
Young adults aged 18-25 suffer outsized rates of opioid deaths and traffic fatalities, per CDC data.

Key quotes

"The law treats eighteen-year-olds like adults and twenty-one-year-olds like superadults." - Laurence Steinberg

"We're not ready for adult responsibilities until our mid-twenties." - Neuroscientist Sarah-Jayne Blakemore

Why it matters

This brain science versus law tension could prompt reforms to age thresholds for voting, contracts, or sentencing, protecting vulnerable young people while granting rights based on biology. Societies risk mismatch-induced harms like addiction epidemics if ignoring maturity gaps. Watch for legislative pushes in 2025+ to align laws with 25 as the new adulthood benchmark.