I've gotten many good insights from Chris Mooney. In a 2004 story in the Columbia Journalism Review called Blinded by Science, for example (
oddly unlinkableposted here), he criticized the journalistic tradition of "balance," as it applied to climate change. He explained that although including diverse points of view gives an impression of objectivity, this habit was giving undeserved credibility to the rare deniers of the consensus on climate. In the intervening years, journalists have become more aware of this problem and more frank in distinguishing the mainstream from the fringe (supported by the increasingly dire predictions of the mainstream view).
In one small section of their recent book, Unscientific America: How Scientific Illiteracy Threatens Our Future, Chris and his coblogger at The Intersection, Sheril Kirshenbaum, expand on this and other ways that journalistic traditions obscure scientific realities. Chief among the disconnects is the news focus on, well, news: what's happening now that we didn't know yesterday? Such event-driven coverage serves poorly many ongoing trends in science (as well as in other areas) that develop continuously or incrementally. The need for a "hook" drives reporters to focus on specific articles in the big journals, rather than the accumulating evidence that they are merely an example of.
Journalists are also prone to framing stories around human elements, especially conflict. There are good reasons for this: people read these stories. But the focus on personalities or revolutions often distracts from the real issues. Biobloggers Larry Moran and T. Ryan Gregory, for example, routinely complain about the misleading narrative that "scientists used to think most of the genome was 'junk," but now they've realized it's good for something." (Scientists have long known that much of it was good for something. Much of it is still junk.)
These differences--driven largely by the business of journalism--are important. Scientists who can't follow Mooney and Kirshenbaum's dictum to transform into public communicators would do well to appreciate what happens to their message when it leaves their hands.
Nonetheless, as someone who has morphed from one to the other, I think the similarities between scientists and journalists are greater than the differences. At a fundamental level, both are professionals dedicated to uncovering reality, wherever it lies. Both groups rely on evidence, and treat personal opinions and popular fads with suspicion, as much as they can recognize them. In each profession, there is a strong social obligation that transcends any loyalty to one's employer or even to one's own prejudices. It is an obligation, as best one can, to speak the truth.