Yes, the political elite have become more partisan and ideological. And yes, they've dragged a lot of the chattering class and even everyday people farther to the left or the right. What this study finds is a whole lot of people still answer liberal on some policy questions and conservative on other policy questions, so for them the single-item ideological placement question fails to capture who they really are, what they really think.
Or, as the authors note in their conclusions:
Our results show that failing to account for the multidimensional nature of ideological preferences can produce inaccurate predictions of voting behavior for the plurality of Americans who do not call themselves liberal or conservative.Their recommendation? Ask more questions. Don't rely only on that good old fashioned liberal-to-conservative question to classify people, because for those in the middle, it fails to capture what people really think and believe. Add policy questions since people can sometimes be fiscal conservatives and social liberals, or some other mix.
What's the media angle here? I think the fragmentation of the news media (see Fox vs MSNBC) is dragging a lot of people, kicking and screaming, into the same partisan divide elites began sharing many years ago. Listen to Sean Hannity, for example, and you'll hear him push for a whole slate of consistent ideological beliefs across the spectrum. I'd love to know if "talk radio conservatives" are more consistent in their ideological beliefs than "non-talk radio conservatives." Ooooh, future study.
Study specs: Clarke, H.D. & McCutcheon, A.L. (2009). The nature of political ideology in the contemporary electorate. Public Opinion Quarterly, 73, 679-703.