Between birth and seven months of age, the average baby born into a two-parent household hears nearly three times as much babbling, cooing and sing-song questions-and-answers from a woman -- generally the mother -- than from a man, new research shows.
Virtually no single factor -- neither a mother’s education level nor a family’s financial resources -- influences a child’s language abilities and IQ more powerfully than does the amount of parental speech a baby hears. Pediatric researchers from Women & Infants Hospital of Rhode Island sought to discover which parent that speech comes from and how often -- and to which children -- parents dispense it.
What they found is that, even on days when both mother and father were with a baby, the mother engaged in the lion’s share of vocalizations aimed at the child. Babies returned the conversational favor by vocally responding to their mothers’ vocal overtures consistently more often than they did to speech from their fathers.
And mothers, in turn, were more responsive to conversational overtures from their baby girls than they were to those from their baby boys.
That preferential pattern was barely discernible by the time the babies were about seven months old. But a mother’s more consistent early response to a baby girl may help explain why, on average, girls start talking earlier than boys, develop larger vocabularies and greater grammatical complexity than boys, read earlier and spell better. (Another possibility: that girls’ greater responsiveness to vocal cues from the start prompts more ongoing verbal attention from mothers.)
As the babies neared seven months of age, however, their responses to both parents’ speech increased.
The new findings, published Monday in the journal Pediatrics, emerged from a study that recorded and analyzed 16-hour blocks of vocal interaction between babies and their parents, starting from the babies’ first days in the hospital. Twice more over the next seven months -- on days when both mother and father were home -- the researchers had parents switch on a recording device that would pick up any vocal exchange between baby and parent.
The researchers didn’t count crying (or burps or other “vegetative sounds”) as vocal cues.
Long before discernible language emerges, the give-and-take of vocalizations between an infant and his caregiver is thought to serve several key functions: it builds a baby’s sense of effectiveness by teaching that calling out will make someone respond. And it introduces babies to the conventions of human speech and conversation, setting the stage for smooth social interaction.
When a mother’s verbal interactions are minimal -- as often happens when a mother is depressed -- babies can suffer lasting consequences.
A landmark study published in 1995 by researchers Betty Hart and Todd R. Risley found that by the time they were three years old, children growing up in households that received welfare payments heard 30 million fewer words by age 4 than did children growing up in professional families. Further, their parents’ messages were generally more discouraging and negative than were those of more affluent parents.