Thankfully, celebrity scandal ranks lowest among all news preferences. Writing for The Nation, Eric Alterman argues that the lack of interest in this subject is the study’s “most shocking” conclusion. The finding is especially surprising given the “major changes in the news ‘menu,’” that Robison describes, where “substantial coverage” devoted to stories such as Paris Hilton’s incarceration and Anna Nicole Smith’s death.

Yet what is truly fascinating is the explanation for this contradiction between interest and coverage: “Even the smallest shifts in ratings can cause news organizations to alter substantially their news focus,” Robinson writes, and often toward “a lower common denominator.” But these alterations, marked by “saturation” coverage, are often temporary and aimed at capturing the niche rather than the national audience. This harkens back to the earlier, chicken-and-egg discussion of where interest lags behind coverage, and where it exceeds coverage. “That the national news audience does not shift its news diet nearly so quickly as news organizations shift their news menu” is one of the most important take-away messages for journalists in Robinson’s study.

Robinson implies that on a national scale changes in coverage tend to mold public interest rather than vice versa. If so, journalists must be especially cognizant of their influence on not only opinions about the news, but also on what is considered newsworthy to begin with. Responsible editors and reporters like to think they do not pander to people’s basest interests, but rather guide and educate them. So perhaps the more pressing question is not, how have preferences changed, but rather to what degree and how quickly does content influence those preferences? Does a diet of more junk food create an appetite for more junk? Does a healthy diet create the reverse?

And if an outlet such as CNN chooses to even temporarily woo a niche audience for the sake of ratings - by chasing the Anna Nicole Smith story, for example - what is sacrificed with regard to the national audience? Hopefully, reports such as the Robinson’s study will help guide journalists as they try to find answers.

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Curtis Brainard writes on science and environment reporting. Follow him on Twitter @cbrainard.