By Melissa Healy
New York - The lack of a fully formed prefrontal cortex - the section of the brain that keeps an adult "on task" - may help young children accumulate knowledge rapidly, a study has suggested.
Anyone who's seen toddlers "at work" can tell that their learning style is a study in chaos. They move from banging pots to tormenting the cat to demanding food to bursting into tears when they can't open the back door and hurdle off the deck - all in the span of minutes.
But when it comes to the daunting task of mastering language, they are turbo-charged learning machines.
An intriguing article published this week in the journal Current Directions in Psychological Science suggests credit for that ability should go to what a toddler lacks - a fully formed prefrontal cortex, the same thing that makes dad so good at filtering out distractions and getting things done.
Babies are born with the foremost part of the brain - the prefrontal cortex - very unde-veloped. For children developing normally, it takes about four years for that so-called seat of higher reasoning to catch up with the rest of the brain in size and complexity. (For children with attention-deficit hyperactivity disorder, such maturation takes longer; for those with autism, the prefrontal cortex develops early.)
This would explain why toddlers are inattentive, distractible and live in the moment. When developed, the prefrontal cortex plays a key role in suppressing impulses, focusing on the task at hand and setting priorities among competing demands.
Yet by the time a typical child is four, they will have learned to speak and will have learned all kinds of complex cause-and-effect connections - that climbing up a slide's ladder will yield a fun ride down, that stealing a friend's toy will bring a reprimand.
In those crucial four years, a toddler's accumulation of knowledge about their world may be unhampered by the discipline imposed by the prefrontal cortex, suggests a trio of neuroscientists from the University of Pennsylvania and Stanford University.
The prefrontal cortex doesn't stand in the way and try to keep them "on task". And their underdeveloped powers of attention will keep them from getting bogged down by pesky exceptions to rules of grammar or syntax. So, they'll always apply the most general rules they know - say, that adding an "s" makes things plural.
The authors call this period of disorderly learning "cognition without control".
This is a theory, not a finding, note the authors, led by the University of Pennsylvania's Sharon Thompson-Schill: that evolution may have favoured a delay in the maturation of the brain's "braking system" as a means of allowing rough-but-rapid learning of complex matters such as language and social conventions.
But it's a theory that might help clinicians and educators begin to identify the best windows for teaching toddlers and for helping those with developmental differences. - LA Times