How Kids Learn
Babies are quick studies-and parents are cramming them with Mozart and French lessons
Cognitive researchers say that they never intended these periods to be considered windows that slam shut. The theory of critical periods arose not out of behavioral research but from 1960s studies showing that kittens kept from using one eye during the first three months of life never regained their sight. While basic systems such as vision and speech require specific sensory experiences to develop correctly, neuroscientists can't say for sure whether any other brain functions have periods when stimulation is critical for normal development.
Indeed, the latest research indicates that the brain continues to grow throughout life to adapt to experience: It's almost indefinitely resilient. Even children who suffered extreme sensory deprivation in infancy, such as those in Romanian orphanages, have largely caught up once placed in a normal environment.
There is broad consensus, however, that children who aren't getting enough stimulation at home can fall behind their peers. Researchers at the University of Kansas found that mothers on welfare were less apt to engage their toddlers in conversation: The average child in a welfare family heard 616 words an hour, compared with 2,153 words in families headed by professionals. Chronic stress, whether from neglect or an unstable family situation, can short-circuit learning; elevated levels of the stress hormone cortisol may retard neuronal growth. Megan Gunnar, a professor of child development at the University of Minnesota, has found babies with insecure relationships with their parents secreted extra cortisol when confronted with scary situations while levels in babies with strong parental ties remained normal.
For children in nurturing environments, however, less seems to be at stake. Parents may want to do everything right, but it may not be essential to the child's ability to thrive. When Peggy Brummond's son Shane, now 2, was floating in utero, she listened to Mozart. The night the newborn came home to Clarendon Hills, Ill., his parents placed him in a bassinet and "had classical music playing all night long." When he hit 18 months, Peggy brought home some lapware. Was it all for naught?
Little things. Not at all, developmental psychologists say, as long as parents don't substitute classes for conversation and software for strolls in the park. That's Bruer's message as well. "Children get all of the stimuli they need from things they encounter in the everyday world-crawling in grass, playing with pots, hearing you speak."
Indeed, too much enrichment can be a dangerous thing. Parents who drill their infants with flashcards for hours on end also run the risk of overloading them. In studies, children show when they've had too much by turning away, closing eyes, or starting to fidget or cry, according to the University of Michigan's Sameroff. Other researchers second the caution. Shonkoff, chair of the National Academy of Sciences committee, says that "artificial pressures from a superenriched environment-particularly when anxious parents are standing by, waiting for their child to succeed-can be detrimental."
So what are Peggy Brummond and other well-meaning parents to do? Is Baby Mozart too much? Is Barney too little? "Relax, and let go of the guilt," advises Joan Goodman, director of the Early Childhood Education Program at the University of Pennsylvania. But don't be ashamed: Go ahead and fire up that Bionic Baby Brain Builder mini-laptop. Then hide it under the sofa, get on your hands and knees, and help your child to peek under pillows and toddle along on a magical treasure hunt.
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