While no specific age has been identified as the age at which the human brain is fully mature, the Washington Post relates that many scientists agree that the brain does not reach maturity until at least the mid-20s. Some studies suggest that the brain continues to develop into the early 30s.
Jay Giedd, a pediatric psychiatrist and the leading researcher for a study by the National Institute of Health, concluded that the region in the brain that controls risky behavior does not fully develop until around age 25. Additional studies at the Institute of Cognitive Neuroscience at the University College London used MRI scans on the brains of 200 individuals aged 7 to 27 and concluded that the prefrontal cortex of the brain, which governs decision making, was forced to work harder in young people than in the brains of older adults.
Children and young adults have more grey matter in their brains, and some researchers believe that this impedes the efficiency of young brains to process information. As people age, the amount of grey matter in the brain decreases and neural transmissions happen with much greater speed and efficiency.
The Washington Post reports that teenagers are four times more likely to be involved in car accidents and three times more likely to die in one. While science has not yet developed a correlation between changes in the brain and how it impacts behavior, many believe that more research needs to be done in this area.