squarely on some of their most beloved cartoons. abc's dan harris explains. >> i want -- >> reporter: check out what happened when my friend and colleague, abc's bob woodruff, took his litite girls to the supermarket. >> scooby-doo crackers. >> you like those? >> yeah. >> have you ever had them? >> no. >> how do you know you like them?รง >> i love them so, so, so much. >> reporter: the new study from john hopkins says cartoon characters play a key role in getting children to nag their parents for fatty foods. >> you like those? >> i like these. >> how do you know? >> because. >> reporter: critics say food marketers ow this and exploit it. i called the author of the study, a researcher by the name of dina borzekowski, and i asked her, what does she think? does she think cartoon characters like fred flinstone and tony the tiger should be banned the way joe camel was? heanswer is no, but she says she hopes food companies will start using cartoon characters