When Does Your Brain Grow Up?

It has long been assumed that the human brain has fully matured by the time someone is 18 years old. After all, that is the age where a teenager legally transitions into a young adult. Rules, rights and opportunities begin to open up for individuals at 18 because they are labeled as “mature.” This categorization of adolescents as mature adults often leads to some confusion, and can be a dangerous public policy if the facts are overlooked.

The truth is that growth and highly important development continues to occur well after one’s teenage years. Over the past few decades, there has been a tremendous amount of research done on the maturation of neuronal networks. Now there is clear evidence that the brain does not mature fully until about age 24. One of the areas of the brain that matures late is the prefrontal cortex the area important in impulse control risk-taking behavior and judgment. Even further, experts now refer to ages 18 through 24 as “time-critical” for one’s brain to reach full adult maturation.

Understanding what the latest studies of the brain continue to prove is key for everyone from parental guardians to public policy makers. Young adults are usually only just beginning to become self-reliant and develop deep relationships with peers, so creating and enforcing the legal and moral structures that they live in must take that into account. “Very little is normative,” during this phase of life. Neural growth and maturation – the development of one’s prefrontal cortex being the most pivotal – does not happen until late adolescence. This means that an 18 year old individual, though considered a legal adult, is quite possibly still developing the neural tools to grow.

Further research on the younger brain suggests that while adolescence is a major factor in overall cognitive maturity, the level of dopamine in the mind of a teen directly supports developmental effects of rewards on cognition. Thus, brain maturation is also dependent on individual chemical processing.

For more details on age and brain maturation, check out this NPR interview with neuroscientist and author, Sandra Aamodt.