Babies and the brain evolution

Why aren’t babies born talking? We know that part of the answer that babies have to listen to themselves to learn how to work their articulators, and have to listen to their elders to learn communal phonemes, words, and phase orders. ….

Before birth, virtually all the neurons are formed, and they migrate into their proper locations in the brain. But head size, brain weight, and thickness of the cerebral cortex (gray matter) where the synapses (junctions) subserving mental computation are found, continue to increase rapidly in the year after birth. Long distance connections (white matter) are not complete until nine months, and they continue to grow their speed-inducing myelin insulation throughout childhood. Synapses continue to develop, peaking in number between nine months and two years (depending on the brain region), at which point the child has fifty percent more synapses than the adult! Metabolic activity in the brain reaches adult levels by nine to ten months, and soon exceeds it, peaking around the age of four. The brain is sculpted not only by adding neural material but by chipping it away. Massive numbers of neurons die in utero, and the dying continues during the first two years before leveling off at age seven. Synapses wither from the age of two through the rest of childhood and into adolescence, when the brain’s metabolic rate falls back to adult levels. Language development, the, could be on a maturational timetable, like teeth. Perhaps linguistic accomplishments like babbling, first words, and grammar require minimum levels of brain size, long-distance connections, and extra synapses, particularly in the language centers of the brain.

So language seems to develop about as quickly as the growing brain can handle it. what’s the rush. Why is language installed so quickly, while the rest of the child’s mental development seems to proceed at a more leisurely pace? In a book on evolutionary theory often considered to be one of the most important since Darwin’s the biologist George Willims speculates:

“We might imagine that Hans and Fritz Faustkell are told on Monday, “Don’t go near the water,” and that both go wading and are spanked for it. on Tuesday they are told, “Don’t play near the fire.” And again they disobey and are spanked. On Wednesday they are told “Don’t tease the saber-tooth.” This time Hans understands the message, and he bears firmly in mind the consequences of disobedience. He prudently avoids the saber-tooth and escapes the spanking. Poor Fritz escapes spanking, too, but for a very different reason.”

Even today, accidental death is an important cause of mortality in early life, and parents who consistently spare the rod in other matters may be moved to violence when a child plays with electric wires or chases a ball into the street. Many of the accidental deaths of small children would probably have been avoided if the victims had understood and remembered verbal instructions and had been capable of effectively substituting verbal symbols for real experience. This might well have been true also under primitive conditions.”

Perhaps it is no coincidence that the vocabulary spurt and beginnings of grammer follow closely on the heels of the baby, quite literally – the ability to walk unaccompanied appears around fifteen months. ~ Page289/290