Should we adjust our views on young children and the set?

Pre-schoolers who watch TV fare slightly better at school, an American report claims, although other experts, both in the US and UK, still advocate a prudent approach. Anjana Ahuja reports.

Don't know whether to let your young children watch TV? The academics don't know either. Scan news releases issued by the National Literacy Trust, whose Talk To Your Baby campaign urges parents to think carefully about their children's relationship with the box - (from May 2004): TV can help language development; (July 2004): Is television destroying children's minds?; (July 2005): Television-watching during childhood linked to poor educational achievement.

As well as stunting communication skills, TV has been blamed for attention deficit hyperactivity disorder (ADHD), bullying, obesity and a lack of reading. Only this week Harvard University reported that among 500 children aged 11 and 12, viewing led to the consumption of 167 extra calories, mostly from junk food. Now a study by the University of Chicago suggests that pre-schoolers who watch TV fare marginally better at school than those who do not. Professor Matthew Gentzkow and Dr Jesse Shapiro began with the premise that current comparisons between those who watch and those who don't may be flawed.

Being economists, they noted that children who watch less tend to come from richer families, and so may enjoy advantages (better schooling, say) that also affect their educational achievement. To try to straighten out this skewing factor, the researchers travelled back in time to see if the arrival of TV in America in the late 1940s was followed by a nationwide drop in educational attainment. The box became immediately popular across all kinds of households.

Shortly after its introduction, American pre-schoolers watched an average of three to four hours a day. The economists studied the scores of more than 300,000 students who sat tests in 1965. The students were aged 11, 14 or 17, and were born during the period of TV's introduction (1948 to 1954). So, within each age group, some had spent their pre-school years watching TV and some hadn't. The surprising conclusion? That test scores were unaffected.

"We find strong evidence against the prevailing wisdom that childhood television viewing causes harm to cognitive or educational development," say Gentzkow and Shapiro. In fact, pre-schoolers who watched TV performed marginally better at school, particularly in reading and general knowledge. This finding persisted even when researchers corrected for other factors that influence test scores: school quality, income and urban deprivation. The young watchers who gained most were: non-whites; those in households where English was not the first language; and those with poorly educated mothers.

The study has yet to be peer-reviewed; it is a working paper released by the National Bureau of Economic Review, and has been submitted to the American Economic Review. Its take-home message is that rather than TV-watching being intrinsically good or bad, its impact depends on what other activities are crowded out. The researchers studied this point in more detail by seeing whether children were read to by their parents; those who were never read to benefited most from TV. Pre-schoolers whose parents read regularly performed slightly worse, though the drop in test score was not statistically significant.

The 'crowding out' hypothesis of TV's effects finds support in a study by the University of Texas at Austin, Zero to Six: Electronic Media in the Lives of Infants, Toddlers and Pre-schoolers. Dr Elizabeth Vandewater and Dr Ellen Wartella found a link (not a good one) between TV and reading. In 'heavy TV' households (where the box is switched on most of the time), 24 per cent of children aged two and over could read; in other homes the figure was 36 per cent. Shockingly, the survey found that a quarter of American children under two have a TV in their bedroom.

That TV can be a force for good is being recognised, though advice differs according to the age of the children and programme content (Gentzkow's study did not look at content). There is little research on how under-twos interact with TV, partly because it is hard to assess how children without language make sense of what they see. For this reason the American Academy of Paediatrics (AAP) recommends that under-twos should not watch any TV, and that interaction with adults and other children should be the main stimulus for infants. The National Literacy Trust (NLT), which conducted a thoughtful review of the literature on TV's effect on language development, sees this stance as 'prudent'.

Liz Attenborough, of NLT's Talk To Your Baby campaign, says: "Unmediated television for very young children is not a great thing," especially for under-threes who watch more than half an hour a day. "Children don't learn to speak by osmosis. They can't learn from passive noise. They need eye contact and a chance to babble back." She adds that having the telly on distracts parents, who then fail to engage fully with their child, and that parents "should be bolder about saying no to TVs in children's bedrooms."

The AAP's strict position was based, in part, on the research of Dr Dimitri Christakis at the Children's Health Institute at the University of Washington. His 2004 study of some 1,300 children showed that, between the ages of one and three, every extra hour of TV raised the risk of that child developing attention problems by 10 percent (those who watched for three hours a day had a 30 per cent risk at age seven). His team, which published the results in Paediatrics, concluded: "There's no safe level [of television-watching] as there's a small but increased risk with each hour." Christakis suggested that pre-schoolers attuned to 'un-naturally stimulating' programmes found it hard to cope with the slower pace of school and home life later on.

But last month's issue of Paediatrics has research refuting the presumption that TV-viewing causes ADHD. Academics from Texas Tech University studied the viewing habits of 5,000 American pre-schoolers and measured how many had ADHD diagnosed in the first year of school. The researchers found not connection; they posit that inattentive children are more likely to watch TV in the first place, perhaps because their parents are more exhausted and so more inclined to resort to the box as an electronic babysitter. So a high diet of TV may be a consequence of the ADHD, not the other way around.

The AAP's opinion is that over-twos can benefit from TV. Its website states: "High quality, non-violent children's shows can have a positive effect on learning. Studies show that preschool children who watch educational TV programmes do better on reading and math tests than children who do not." Christakis's team suggested that over-twos should watch for no more than two hours a day. The NLT agrees that, for children aged between two and five, "there is evidence that attention and comprehension, receptive vocabulary, some expressive language, letter-sound knowledge, and knowledge of narrative and story-telling all benefit from high quality and age-appropriate educational programming."

(Times2, 11.04.06)