Parents may realize that frequently using the TV as a babysitter is linked to various health and mental health concerns in children. But they may not realize the possible long-term effects.
A recent study tracked children from birth through age 26. The researchers compared the children's early TV watching habits with their later aggression and criminal convictions.
The results showed that kids who watched more TV were more likely to end up with a conviction or with aggressive or antisocial behaviors. The authors recommended that children watch less than two hours of TV a day.
The study was led by Lindsay A. Robertson, MPH, of the Department of Preventive and Social Medicine at the University of Otago's Dunedin School in New Zealand.
The researchers tracked 1,037 New Zealand children from birth, in 1972-73, until they were 26 years old. They gathered data on how much television the children watched between the ages of 5 and 15.
Then the researchers assessed the number of criminal convictions and violent convictions the children had as adults. The kids were also assessed for diagnosis of antisocial personality disorder and aggressive personality traits using standard psychology assessments.
On the personality assessment used, "individuals scoring highly on Aggression tend to hurt others for their own advantage and frighten and cause discomfort for others," the authors reported.
At follow-up assessments during ages 5, 7, 9, 11, 13, 15, 18, 21 and 26, at least 90 percent of the participants were interviewed (except 82 percent at age 13). So, the majority were included throughout the study. The children came from a variety of socioeconomic backgrounds.
Until age 13, parents reported how much time the participants watched TV during weekdays. Then the children themselves reported their TV time at ages 13 and 15.
On average, the kids watched about 2.3 hours of TV a day from ages 5 to 15, and boys watched a little more (about 10 minutes more daily) than girls.
In general, the researchers found that children who watched more television were more likely to have a criminal conviction than those who watched less television. They were also more likely to have aggressive personality traits as adults and have a diagnosis of antisocial personality disorder.
These associations were large enough to be considered related to the TV watching and could not be dismissed as chance. Even when the researchers considered other characteristics of the children, the findings remained the same for both girls and boys.
The researchers took into account in their analysis the children's sex, IQ, socioeconomic status, past antisocial behaviors and the level of parental control over their children.
Parental control was determined with a questionnaire taken by the mothers when the kids were 7 and 9 years old. It related to how many rules were used in the family and what kids "got away with."
"Our findings are consistent with other longitudinal studies that found that the amount of television viewing in childhood or adolescence predicted subsequent antisocial behavior," the researchers wrote.
However, their study was limited because it did not track what programs the children were watching. They therefore cannot be sure whether the content of what kids watched made a difference. They could only conclude that the amount of TV watching in general was linked to future problems.
"Excessive television viewing in childhood and adolescence is associated with increased antisocial behavior in early adulthood," the researchers wrote. "The findings are consistent with a causal association and support the American Academy of Pediatrics recommendation that children should watch no more than 1 to 2 hours of television each day."
The study was published February 18 in the journal Pediatrics. The research was funded by the the New Zealand Health Research Council, the US National Institute of Mental Health and the William T. Grant Foundation. The authors declared no conflicts of interest.