When does the human brain stop growing?

Until relatively recently, scientists believed that a human being's brain growth was complete and the structure was essentially fixed by age 3. Of course, connections between neurons were rewired as children acquired information, but for the most part, the blueprint for the brain was set.

With the use of magnetic resonance imaging (MRI), however, scientists have been able to see inside the brain and to learn that the brain apparently undergoes a growth spurt during the teenage years.

This may help explain why teens seem to turn into an army of emotional loose cannons.