The majority of the claims came from advertisers. Advertisers probably feed more science to Americans than anyone else, which is not surprising since they are in the business of making claims, and the same NSB study cited above noted that Americans are all ears about science: 90 percent
of respondents were moderately or very interested in new scientific discoveries. Companies have a legal obligation to tell the truth (not always obeyed, of course; promising "3+ full inches" would seem to be a heartbreaking lie), but they have a marketing imperative to put the best possible spin on it. The marketing imperative is, of course, antithetical
to the scientific method.
Science proceeds slowly, painfully, and with considerable uncertainty: The cholesterol?heart disease connection has been researched for more than 50 years, and it's still not completely understood. In simplest terms,
science is gray. Science in advertising wears makeup?it sometimes looks 20 years younger and has huge breasts and a, well, you get the picture.