How three hours' TV a day can leave toddlers weak, stunted and aggressive
TODDLERS who watch three hours of TV a day may end up educationally stunted, physically weak and emotionally aggressive.
After two hours of viewing, every extra hour of television has the potential to harm a child's development, both physically and socially.
Excessive screen time among three-year-olds is also a strong risk factor in developing obesity, researchers have found.
Emotional issues, hyperactivity and difficulties interacting with peers are all linked with too much exposure to television.
"Compared to children who watch less TV, avid child television watchers can have more problem behaviours," explained study co-author Aisling Murray, research analyst from the ESRI.
"They might have problems getting on with other children and can be aggressive.
"It can result in 'acting out' behaviour, anxiety, or the child being withdrawn."
She was one of a number of contributors to a day-long conference in Croke Park on the theme 'Growing Up In Ireland'.
Family factors and individual differences can also influence a young child's socio-emotional development, she added.
"But some children may have a tendency towards aggression and choose to watch more violent programmes," she told the Irish Independent.
There is also a concern that children may go on to develop a "pattern of behaviour" in middle childhood, which revolves around television at the expense of outdoor activities.
The American Academy of Paediatrics (AAP) recommends no more than one to two hours per day watching television for children. But 27pc of three-year-olds watch more than this recommended figure.
And the problem is worsened because 16pc have a television, a computer, or a games console, in their bedroom.
She said the types of programmes three-year-olds are watching is a significant factor in determining the effect on their cognitive development.
Study co-author Suzanne Egan, from Mary Immaculate College at the University of Limerick, said educational content tailored towards children may improve language skills.
"But if they're watching things that aren't appropriate, it can work the other way, and have a negative impact.
"We found that, in general, the longer they watch TV, the more difficulties they had." Too much TV can also leave them physically weaker, she added.
"There is a link between the amount watched and BMI (body mass index) levels and obesity.
"A study last year indicated there is a risk of being overweight or obese, and long hours of screen time.
"Spending longer watching television displaces other stationary activities such as reading and playing.
"The research is mixed but it might be that they're snacking more while they watch television." Flashing imagery from watching TV late at night can also exacerbate behavioural problems.
"The bright screen can interrupt sleep. So if they're watching inappropriate content, young children may suffer from nightmares, which keeps them awake," said Ms Egan.