National Geographic : 2015 Jan
70 national geographic • january 2015 absorbed what was correct. “Somehow they must have learned it, despite not comprehend- ing the meaning of the sentences,” Friederici tells me. “At this point it’s not syntax. It’s phonologi- cally encoded regularity.” Researchers have shown that children around two and a half years old are savvy enough to cor- rect grammatical mistakes made by puppets. By the age of three most children seem to master a considerable number of grammatical rules. Their vocabulary burgeons. This flowering of language ability comes about as new connec- tions are made among neurons, so that speech can be processed on multiple levels: sound, meaning, and syntax. Scientists have yet to un- veil the precise map followed by the infant brain on the path to linguistic fluency. But what’s clear, in the words of Friederici, is this: “The equip- ment alone is not enough. You also need input.” On my way to Leipzig to interview Friederici, my attention is drawn to a mother and her young son, engaging in conversation on a shuttle bus at the Munich airport. “What do you see in the distance?” the mother asks as the bus takes us from the terminal to the aircraft. “I see a lot of planes!” the kid exults, bouncing. Seated in a row ahead of me on the flight, the two keep up an unflaggingly spirited exchange. The woman stops to answer the boy’s every question as she reads him one picture book after another, draw- ing on what seems like a limitless reservoir of enthusiasm. When we land, I learn that the mom, Merle Fairhurst, is a cognitive neuroscientist who studies child development and social cognition. It isn’t surprising that she is determined to apply the emerging research on how stimulation can help the developing brain. More than two decades ago Todd Risley and Betty Hart, both child psychologists then at the University of Kansas in Lawrence, recorded hun- dreds of hours of interactions between children and adults in 42 families from across the socio- economic spectrum, following the kids from the age of nine months to three years. Studying the transcripts of these record- ings, Risley and Hart made a surprising dis- covery. Children in well-off families—where the parents were typically college-educated In the neonatal intensive care unit at Texas Children’s Hospital in Houston, five-month-old Lucas Guidry watches as mom Sydney (center) holds up a mirror. Children born prematurely or with an illness are at risk for cognitive delays.