Photo

I always wanted somewhat cynical children, at least where advertising and proselytizing are concerned. That is, I wanted my children to grow up alert to the silken, studied salesmanship of those who want your trust but are not really your friends.

I grew up in the era of unfettered television advertisements for tobacco. I remember all the jingles — but I also remember the welcome cynicism of Mad Magazine parodies in which gravestones discussed the great taste of cigarettes and Hitler endorsed them as terrific mass murderers.

In serious discussions of advertising today, I sometimes miss that harsh humor. Researchers have long focused on the effects of cigarette and alcohol ads on children — and more recently, on the effects of subtler marketing through product placement in movies and TV shows. Studies show that advertising does help push children and adolescents toward unhealthy behaviors, but also that it is increasingly difficult to shield them as marketers exploit the Internet and social media.

In a study published last month in the journal Pediatrics, Jerry L. Grenard, a health researcher at Claremont Graduate University, and his colleagues followed almost 4,000 students from seventh through 10th grades, assessing their exposure to alcohol advertising on television and asking about their alcohol use.

A large body of literature shows that advertising does increase the odds of underage drinking, Dr. Grenard noted. But his new results take the concerns a step further. “This study linked exposure to alcohol advertising to an increase in alcohol use among adolescents and then that in turn is associated with higher level of problems with drinking alcohol, getting drunk, missing school, getting into fights,” he said.

Adolescents who see alcohol advertising are being sold something that we would prefer them not to consume in any amount. Food advertising raises different issues, since children will certainly eat and will certainly have — and express — food preferences.

Jennifer Harris, the director of marketing initiatives at the Yale Rudd Center for Food Policy and Obesity, told me that television advertising remains very important in the ways that foods are marketed to children. According to the center’s data, every day on average in the United States, children and teenagers see 12 to 14 food ads on television.

But parents may not realize that their children are also subjected to messages from advertisers coming in from other directions.

“They have Web sites with reward programs. They’re advertising on other Web sites, social media — Facebook is huge — Twitter, mobile marketing, mobile apps,” Dr. Harris said. Many children are playing “advergames” online, for example, intended to promote products. Parents may be completely unaware, she said.

And what are they marketing to children? According to Dr. Harris, the top four products are fast foods, sugared cereals, sugary drinks and candy.

Thomas Robinson, a professor of pediatrics at Stanford University and Lucile Packard Children’s Hospital, has studied childhood obesity and its links to screen time. In experiments with preschoolers, he told me, “even a 30-second exposure to a novel product, one that you’ve never seen before, changes their preferences for brand.”

In another study, researchers looked at the effects of branding by giving 3- to 5-year-olds two portions of identical foods, one set out on a McDonald’s wrapper. The children were asked to point to which foods tasted better and, Dr. Robinson said, “overwhelmingly, for hamburgers, French fries, baby carrots, milk or juice in a cup, kids would say the one on the McDonald’s wrapper tastes better.”

Up to the age of 7 or 8, children are thought to be unable to understand the nature of advertising — developmentally, they can’t identify the underlying persuasive intent.

Older children may have a better understanding of commercials, but they are vulnerable in other ways.

“Coke is the most popular brand on Facebook,” Dr. Harris said. “It has 58 million fans.” When adolescents “like” Coke, they receive posts every day, which they may then “share” with friends.

“That whole tapping into the peer relationship that kids of that age have is, we think, very deceptive,” Dr. Harris said. “They don’t necessarily recognize that it’s advertising and also very manipulative.”

What can parents do? With young children, the most important strategy is probably to reduce screen time, and the number of messages, and to keep track of what they’re seeing when they do watch TV.

And when a child asks for something, parents should not simply refuse. “Respond, ‘Well, why do you want that? Where did you hear about it?’ ” said Dr. Robinson. And if the answer is that the child saw it on TV or on the Internet, “Say, ‘Well, they want you to want it, they’re trying to sell you that.’ And then have a discussion.”

And what about my aspirations of nurturing young cynics? Though teaching critical viewing skills does enhance children’s awareness, Dr. Robinson told me that relying too much on notions of media literacy can actually play into the hands of the advertisers.

“That takes the responsibility away from them and puts it on the kids to be educated consumers,” he said.

Know what your children are watching. Watch with them. Talk about what you see — the images on billboards or on touchscreens, the Super Bowl commercials, the Web sites they visit.

In an information-rich world, we need to know the messages children are receiving, and help them decode and understand what the world is trying to sell them.