Saturday, October 24, 2009
Brain cells are “raw” materials — much like lumber is a raw material in building a house. Heredity may determine the basic number of “neurons” (brain nerve cells) children are born with, and their initial arrangement, but this is just a framework. A child’s environment has enormous impact on how these cells get connected or “wired” to each other. Many parents and caregivers have understood intuitively that loving, everyday interactions — cuddling infants closely or singing to toddlers—help children learn.
A brain is not a computer. The brain begins working long before it is finished. And the same processes that wire the brain before birth also drive the very rapid growth of learning that occurs immediately after birth. At birth, a baby’s brain contains 100 billion neurons, roughly as many nerve cells as there are stars in the Milky Way. Before birth, the brain produces trillions more neurons and “synapses” (connections between the brain cells) than needed. During the first years of life, the brain undergoes a series of extraordinary changes. Then, through a process that resembles Darwinian competition, the brain eliminates connections that are seldom or never used.
“Windows of opportunity” are critical periods in children’s lives when specific types of learning take place. For instance, scientists have determined that the neurons for vision begin sending messages back and forth rapidly at 2 to 4 months of age, peaking in intensity at 8 months. It is no coincidence that babies begin to take notice of the world during this period.
Scientists believe that language is acquired most easily during the first ten years of life. During these years, the circuits in children’s brains become wired for how their own language sounds. An infant’s repeated exposure to words clearly helps her brain build the neural connections that will enable her to learn more words later on. For infants, individual attention and responsive, sensitive caregiving are critical for later language and intellectual development.
Research does not suggest drilling children in alphabet songs from different languages or using flash cards to promote rote memorization of letters and numbers. Children learn any language best in the context of meaningful, day-to-day interactions with adults or other children who speak the language.
Schools can take advantage of this window of opportunity to teach language. If children are to learn to speak a second language like a native, they should be introduced to the language by age ten.
Early stimulation sets the stage for how children will learn and interact with others throughout life. A child’s experiences, good or bad, influence the wiring of his brain and the connection in his nervous system. Loving interactions with caring adults strongly stimulate a child’s brain, causing synapses to grow and existing connections to get stronger. Connections that are used become permanent. If a child receives little stimulation early on, the synapses will not develop, and the brain will make fewer connections.