"It's called the 'nag factor,'" said Lisa Chamberlain, MD, MPH, Packard Children's researcher and clinical instructor at the medical school, "and it's very effective."
What's more, the correlation between increased screen time and subsequent requests for toys and junk food held true for over a period of 20 months.
Chamberlain warns that, if left unchecked, increasing amounts of screen time for children could foster a rise in obesity and consumerism that will reverberate for decades. She is the lead author of the research, which will be published in the April issue of the Archives of Pediatrics & Adolescent Medicine.
"We're proving what marketers have known for years," said Chamberlain. "Kids have discretionary income of their own, and they also have a lot of influence of how their parents spend the family's money."
Chamberlain collaborated with pediatric researcher Thomas Robinson, MD, for the study. Robinson is well-known for his investigations into the links between television viewing and obesity, violence and test scores. He is also the director of Packard Children's Center for Healthy Weight, and an associate professor of pediatrics at Stanford's School of Medicine.
The researchers surveyed more than 800 ethnically and socio-demographically diverse third-graders at 12 elementary schools in California. They asked the children how much time they spent watching television or watching movies or videos on a VCR. The study also included playing video games. The kids were then asked if, in the previous week, they had asked an adult to buy them any food or drinks they had seen on the screen. A separate question asked about toys.
On average, the children reported spending more than 22 hours of screen time each week - about 10 of which was spent watching television. The remainder of the time was mostly spent playing video games online or on home video game machines, both of which incorporate increasing amounts of advertising targeted to children.
The children fessed up to about one request each week for toys and two requests every three weeks for food or drinks. These numbers are similar to those reported in other studies.
More than 300 of these children from six of the schools also answered the same questions seven, 12 and 20 months after the initial assessment. The researchers found that those who watched more entertainment than their peers at the beginning of the study wanted more stuff nearly two years later - to the tune of one extra toy request every three to four months and one extra food or beverage request every three to six months for every additional hour of screen time daily. Although this may not seem like a large increase, it's statistically significant for snacks, and maddening to their verbal targets - Mom and Dad.
"Our result demonstrates that television and other screen media are true 'risk factors' for future requests for food and drinks," the researchers conclude, "regardless of a child's gender, ethnicity, economic standing or language." Chamberlain and other researchers are particularly concerned about the fact that kid-targeted advertising frequently promotes high-calorie, nutritionally poor choices. Legislators interested in obesity prevention in children would do well to turn their attention to the forces that drive kids to make unhealthy decisions, they said.
"Kids are an easy target for advertisers," concluded Robinson. "Younger children aren't even able to understand that ads, which are now cropping up in video games and movies, online and even in cell phones, are intended to sell them things. Marketers need to be part of the solution for the obesity epidemic by helping parents, not making it harder for them."
Stanford University Medical Center integrates research, medical education and patient care at its three institutions - Stanford University School of Medicine, Stanford Hospital & Clinics and Lucile Packard Children's Hospital at Stanford. For more information, please visit the Web site of the medical center's Office of Communication & Public Affairs at http://mednews.
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