Henry James described a baby's world as a "blooming, buzzing confusion." But parents know better. Almost instinctively, they speak to their infants in "motherese" -- a universal language of parents, spoken in a lilting, sing-song, rhyming pattern. And parents around the world are rewarded with burbles and smiles as the babies cut through the confusion and focus on the intonation and rhymes.
"What did you dooo? Did you get a boo booo?" sang a nurse to a baby in a doctor's office last week. The child looked up at her and beamed.
But what is it about rhymes? Why do parents know to spout doggerel to their offspring, and why are many of the most beloved children's books -- from Mother Goose to Dr. Seuss' "Hop on Pop" -- written in rhyming verse? Why is it that when developmental psychologists want to see if preschoolers are ready to learn, they first ask them to find words that rhyme? Why do popular songs rhyme?
Now the first definitive evidence that men and women use their brains differently has come from a study involving rhymes.
Researchers at Yale University School of Medicine asked men and women who were normal readers to study lists of nonsensical words and decide if any words rhymed. Participants had to sound them out, breaking them into phonemes.
As they did, the investigators watched their brains through functional magnetic resonance imaging, a scanning technique that shows areas of the brain into which blood flows as people think.
To their surprise, the researchers discovered that the sexes used their brains differently. Men used a small area near the temple on the left side of the brain; women used that area as well as an area on the right side. Yet both were equally good at the task. The outcome gave no clue to the brain processes involved.
Dr. Reid Lyon, who directs research on reading disabilities at the National Institute for Child Health and Human Development in Bethesda, said reading specialists use rhymes to identify children who might have trouble learning to read.
About 80 percent of kindergartners will readily find, for example, three words that rhyme with "cat." The other struggling 20 percent are headed toward difficulties that will require remediation.
One way to help these children, Dr. Lyon said, is to play rhyming games.
Rhyming may also be a window on the mind, said Dr. Norman Krasnegor, who directs the human learning and behavior department at the child health institute.
Breaking words into phonemes and rhyming is an integral part of language, Dr. Krasnegor said, and "language is part of what makes us human." It may be more than a coincidence that motherese emphasizes rhymes.
"It may be part of what creates an opportunity for learning language," he said.