No wonder Americans call television the âboob tubeâ. Infants vocalise less and hear fewer words from nearby adults when the TV is on, a new study of recorder-toting infants suggests.
âThereâs no question that human voice and human words are what babies need,â says , a paediatrician at the University of Washington in Seattle, who led the study. âThe data are not yet conclusive about the fact that television is harmful, but they continue to mount.â
Christakisâ team equipped 329 infants, aged between 2 and 48 months, with lightweight recorders that captured every noise they heard in a 24-hour period. A computer program â shown in a previous study to be 82 per cent accurate â then determined whether each sound came from the infant, an adult or the television.
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The analysis showed that for every hour of television an infant is exposed to â they donât understand television programmes, Christakis says â he or she hears 770 fewer words from adults, on average, a 7 per cent reduction. Infants watching TV also utter fewer âgoogoosâ and âgagasâ and interact less with adults than children whose parents use the off switch more enthusiastically.
Developing brain
That finding is backed up by observations made by , a psychologist at the University of Massachusetts in Amherst, and colleague Heather Kirkorian. They found that infants exposed to television hear 20 per cent fewer words from their parents during every hour of programming that they watch.
âParents are less engaged with the children if the television is on,â says Anderson, whose findings will be published in a study currently in press at the journal .
Given that a staggering 30 per cent of US households keep a television on at all times, this can have a substantial effect on an infantâs development, according to Christakis.
âThe newborn brain is very much a work in progress. All that cognitive stimulation is critical to the underlying architecture thatâs developing,â he says. âEvery word that babies hear, and every time they hear it, is extremely important.â
âMinimise exposureâ
The audio analysis software wasnât sophisticated enough to determine whether the infants were being exposed to shows aimed at infants or adults. But Christakis says that even programming aimed at children doesnât always live up to its billing. âMany of these DVDs that target infants claim that they promote parent-child interaction â which they donât,â he says.
Christakis was part of a 2007 study which found that infants who watched some such programmes actually scored lower on tests of language development than children who werenât exposed to them. âThe take-home message for parents is to minimise television exposure during the first two years,â Christakis says, a stance endorsed by the .
âChildren over two learn a lot of vocabulary from television, thatâs very clear,â says Anderson. âThe real question comes with baby videos and that remains really controversial.â
Journal reference: (DOI: 10.1016/j.evolhumbehav.2009.03.001)
