An average child in the United States sees about 40,000 commercials a year just while watching television.

With more than 40 million kids online daily, and growing, perhaps no tool has become more important to marketers than the Internet.

I didn’t write those sentences. I lifted them straight out of “Consuming Kids,” a 67-minute documentary from the Media Education Foundation that will be shown at 7 p.m. on Tuesday at the Lawrence Public Library.

I’m quoting the movie because I believe that we have a responsibility to promote the healthy development of children — and because companies that target children for advertising seem to be working against that.

There are concrete things we can do to make sure marketing is more responsible. I’ll mention what people in other states are doing. I hope that on Tuesday we can talk about what people in Lawrence might do.

The bad news is the size of the job we face. Childhood obesity, precocious sexual experimentation, drug use and eating disorders have been linked to advertising targeted at children, according to the American Academy of Pediatrics.

Beyond that, advertising targets kids who aren’t able to realize that they’re the target of a marketing campaign.

As the American Academy of Pediatrics notes, “young children — younger than 8 years — are cognitively and psychologically defenseless against advertising. They do not understand the notion of intent to sell and frequently accept advertising claims at face value.”

And did you know that kids with cell phones are a prime target for marketers these days? That one in four between ages 8 and 12 has one? That the number of children with cell phones is expected to double in 5 years? I didn’t — until I watched the movie.

Marketing exploits children’s developmental vulnerability. Besides the defenselessness of very young children, such marketing manipulates children’s desires to be cool and part of the “in” crowd, undermining their sense of intrinsic self-worth; pits children against adults in general and parents in particular; and offers a world view where the dominant values are immediate self-gratification and the overriding importance of wealth and possessions.

All these are linked to decreased physical and emotional health.

Compounding all of this is the surprising affluence of children, who are estimated to spend $40 billion of their own money and influence another $700 billion in spending annually.

Even so, some parents and community leaders are fighting back.

It happened in Seattle, where a group of parents began a movement to create commercial-free schools that eventually led to prohibitions on school-based advertising. Legislation has been introduced in Massachusetts and Vermont that would severely curtail advertising in schools, and in South Carolina to ban advertising in school buses.

It’s time for people in Lawrence who are worried about this problem to sit down together and talk about what we can do in Kansas. That’s what we will be doing after the movie next Tuesday night; I hope you will join the discussion.

— Gary Brunk, a Lawrence resident, is president and CEO of Kansas Action for Children.