It’s tricky to say definitively when someone’s officially an adult. Some teens might argue they’re adults when they turn 16 and can drive. Others argue 18, when youth typically go off to college or legally are able to join the military. Still others say 21, when it’s legal for them to drink. Neurologists say adulthood doesn’t technically occur until around age 25, when a person’s brain is fully developed.

Recent studies have found that by the time someone turns 18, his or her prefrontal cortex is only half formed, and that’s critical because that cortex is in charge of problem-solving, emotional regulation and impulse control. (Mother Nature Network)