Children who spend hours watching television after school are more likely to become criminals, researchers say.
A University of Otago study found the risk of having a criminal conviction by early adulthood increased by about 30% with every hour children and teens spent watching TV on an average weeknight, co-author Associate Professor Bob Hancox said.
Watching more television in childhood was also associated with aggressive personality traits, an increased tendency to experience negative emotions, and an increased risk of antisocial personality disorder in adulthood.
"While we're not saying that television causes all antisocial behaviour, our findings do suggest that reducing TV viewing could go some way towards reducing rates of antisocial behaviour in society," said Dr Hancox, of the Department of Preventive and Social Medicine.
The American Academy of Pediatrics recommends children watch no more than one to two hours of quality television programming each day.
University of Canterbury sociology professor Greg Newbold said bad parenting, rather than excessive television watching, caused children to become criminals.
"The primary factor, I think, will be the fact that kids who are allowed to watch lots and lots of television have parents who do not play a very active role in their lives. Bad parenting and television are linked and criminality is a consequence of that."
The study, Childhood and adolescent television viewing and antisocial behaviour in early adulthood, was published in the United States journal Pediatrics yesterday.
The research is another strand of the longitudinal study into a group of about 1000 children born in Dunedin in 1972-73. Every two years between the ages of 5 and 15, they were asked how much television they watched. They were then tracked until they were 26.
It is believed to be the first "real-life" study following television viewing throughout childhood, and then looking at a range of antisocial outcomes.
Study co-author Lindsay Robertson said children who watched more television were not antisocial in their younger years. "Rather, children who watched a lot of television were likely to go on to manifest antisocial behaviour and personality traits."
This was not explained by socio-economic status, IQ, antisocial behaviour in early childhood, or lack of parental control.
As an observational study, it cannot prove that watching too much television caused the antisocial outcomes, but the findings are consistent with other research and provide further evidence that excessive television viewing can have long-term consequences for behaviour, Ms Robertson said.
Dr Hancox said a limitation of the study was the lack of information on the type of programmes the children had watched. "We can't tell if it was a particular type of programme or just the fact they were watching TV at all."
The question was whether the content contributed to violent and antisocial behaviour later in life, or whether the amount of time spent watching television meant children did not develop pro-social behaviour and life skills, he said.
But there was enough evidence to come to a conclusion backed by other studies.
"Children who watch violent TV behave in a violent way afterwards and people who watch a lot of TV are more likely to have bad behaviour later in life."
Excessive television viewing in younger years is associated with increased antisocial behaviour in adulthood.
The link between television viewing and antisocial behaviour in adulthood was similar for boys and girls.
However, antisocial outcomes were less common in women.
The connection between television viewing and violent convictions were not significant after controlling for other factors.