- 21:00 04 July 2005
- NewScientist.com news service
Too much time in front of the TV reduces children’s learning abilities, academic achievement, and even the likelihood of their graduating from university, suggest three new studies. But it may be the quality, not quantity, of the programmes that really matters.
Decades of studies have linked childhood hours in front of the TV with aggressive behaviour, earlier sexual activity, smoking, obesity, and poor school performance. The research has lead the American Academy of Pediatrics to suggest children watch no more than 2 hours of TV per day and that children under 2 years old watch none at all.
But results from studies on cognitive abilities and TV watching have been mixed. Some researchers have found that high quality, educational TV programmes are a boon for learning. Others have shown that the negative effects of hours in front of the TV disappear when confounding factors - such as IQ or socioeconomic status - are included.
So Robert Hancox at the University of Otago in New Zealand and colleagues studied nearly 1000 children born in Dunedin, NZ, in 1972 and 1973. The researchers gathered data from both parents and children on how many hours a day were each spent watching TV at age 5, 7, 9, 11, 13 and 15. The team then re-evaluated participants at the age of 26.
Kids who watched the least TV – especially between the ages of 5 and 11 – had the highest probability of graduating from university by the age of 26, regardless of IQ or socioeconomic status. While those who watched the most TV, more than 3 hours per day, had the highest chance of dropping out of school without qualifications.
Furthermore, the effects seemed to be strongest for those who had a median IQ level, probably because the outcomes for the children at either IQ extreme are less likely to be affected by TV watching.
Two other studies, also published in the July issue of Archives of Pediatric and Adolescent Medicine found similar results. Dina Borzekowski at Johns Hopkins Bloomberg School of Public Health and colleagues found that Northern Californian third-graders - aged about 8 - with a TV in their bedroom watched more TV and performed worse on standardised tests than classmates without a bedroom TV.
Frederick Zimmerman and Dimitri Christakis at the University of Washington in Seattle, found that kids who watched the most TV before the age of 3 performed poorest on reading and mathematics tests at ages 6 and 7. But there did seem to be some benefit for TV watching in 3 to 5 year olds, possibly because of the large number of educational programs targeted at this age category, such as Sesame Street. For the duration of this study – 1990 to 1996 – very little educational programming for under-threes was available in the US.
In an accompanying editorial, Ariel Chernin and Deborah Linebarger at the University of Pennsylvania, US, points out that all three studies do not separate the effects of educational versus entertainment programming.
One proposed mechanism of how TV harms educational achievement is that TV takes time away from creative play, reading or doing homework. But, the editorial notes, research specifically examining this suggests "it is not the amount of viewing that matters but the content of what is viewed".
They suggest that parents should encourage kids to watch quality, educational programming. But Barry Milne, a co-author on the New Zealand study and now at the Institute of Psychiatry in London, UK, points out this may be simpler said than done: “Content could well be a confounding factor. But what we did find is that the type of TV kids actually do watch is not good for them."
Journal reference: Archives of Pediatrics and Adolescent Medicine (vol 159, p 607, p 614, p 619, p 687)