Young adult brains keep maturing past age twenty-five
Young adulthood follows adolescence, sometimes overlapping it, and nobody agrees exactly where it ends. The US Census Bureau counts ages 18 to 34, cancer researchers stretch the span to 49, and neuroscientists who once thought the brain was finished near 25 now see it developing into the early thirties.
Erik Erikson framed this stage around forming intimate relationships and a personal identity. Some developmental researchers call it emerging adulthood, a bridge to full adulthood during which the prefrontal cortex, the seat of executive function and decision-making, is still maturing. Courts have begun to weigh that research, with some rulings taking account of the development of offenders under 21 when setting sentences. More than 65 million Americans, born roughly between 1991 and 2008, fall into the category.
Other frameworks slice the years differently. One scheme gives early adulthood the span from about 16 or 17 to 45, the era of greatest energy and greatest stress, opening with an early adult transition from 17 to 22. MIT has tended to use 18 to 22 or 18 to 25, close to typical college ages. There is broad agreement, though, that the twenties and thirties form the core, when Daniel Levinson's Dream, a motivating vision of life goals, takes shape. Longer lives, earlier puberty, costly college and changing housing and work have made the milestones far less predictable.
Physically these are usually the healthiest years, with strength and performance peaking between 18 and 46. Yet risk-taking brings injury, binge drinking, car crashes and suicide, and about three quarters of young-adult deaths stem from risky behaviour or mental health crises. Men aged 18 to 25 die at higher rates than women, a gap that narrows by the late twenties. Cancer is rarer than later in life, except for testicular, cervical and colorectal cancers and Hodgkin's lymphoma. AIDS cut South African life expectancy by 18 years and Botswana's by 34.
Young adults vote less often than middle-aged and older people in many countries. Publishers apply the young adult label to novels aimed at readers as young as 13, a stretch critics dispute.
Source: Young adult
