To the Editor:
On the Minnetonka School District’s website, they argue the benefits of their K-5 immersion language programs.
“Your child’s brain is at the optimal stage of early development to learn language, meaning your child has twice as many synapses (connections) in the brain as you do. These connections must be used or lost. There is a window of opportunity in which your child can learn any first language normally. After this period, their brain becomes slowly less receptive ...”
But this critical learning period or synaptic pruning model is unproven speculation-pseudoscience. A review article on the subject by Dr. John T. Bruer can be found at bit.ly/Bruerarticle.
The model arose out a single neuroscience study published in 1987. There, 29 children from the ages of 5 days to 15 years were given PET scans. A plateau of higher brain metabolic activity was found from the ages of three to nine in those subjects.
Earlier neuroanatomic studies had demonstrated that a few months after birth and continuing until age 3, the brain formed synapses very rapidly. This high synaptic density remains elevated until around puberty when some mechanism, apparently under genetic control, causes synapses to be eliminated or pruned back to lower adult levels.
The lead neuroscientist in the 1987 study originally proposed the “critical learning” model based on these studies. This was quickly accepted as fact by many in the education establishment. However, no subsequent neuroscience research has been done to show how “synaptic pruning” relates to the ease, rapidity and depth of learning in children. To the contrary, other evidence indicates that most learning takes place only after synaptic formation stabilizes.
Minnetonka’s web site quotes another source. “In the early years of English instruction (K-2), there may be a lag in English reading and writing skills. By fifth grade, however, immersion students do as well, or better than students in English-only classes.”
This suggests, as common sense would dictate, that language learning in children is a zero-sum game. When a competing second language is introduced, Peter will invariably be robbed to pay Paul.