Finally, a light at the end of childhood.
Researchers at the National Institute of Mental Health and UCLA have been exploring how human minds mature, when they do. It's tricky enough just to live this journey, let alone to track it medically for 17 years. The researchers found that parts of the brain's 100 billion neurons matured at different times.
This makes intuitive sense to parents, who've watched their babies' progress from babbling infants to inquisitive toddlers to rambunctious kindergartners to chaotic grade-schoolers. Then come the high school years, which are hard to describe in a family newspaper. Parents' witness their beloved's little mind expand, watching oral eloquence, visual acuity and coordination evolve for years. This makes a long series of challenges for adults raising future adults.
The researchers also found, however, that the mental neighborhood responsible for reasoning was the last to mature. Eureka! This explains age 15.
At that point, or slightly before, parents observe a vast void developing within the thickening skull of their new teenager, as if the brain were shrinking.
The inner space seems to contain vast galactic clouds of behavioral gas swirling in unpredictable cyclones of emotion and hormones, producing pouts and worse. Communicating across this void of reason can involve lapses in time and patience requiring louder repeat transmissions. Come here! Come here!
These scientists, all of whom presumably experienced teendom, periodically scanned 13 youngsters' brains from 4 to 21. Assembling composite time-lapse images of brain growth, they saw that front and back brain areas matured first; these process basic functions like smell, hearing and sight. Next the brain's uptown, governing touch and movement. Then next to develop is the parietal lobes, controlling language and spatial orientation. Finally left to develop is the most complex mental arena, the prefrontal cortex, which integrates the...