Had chance to look closely at the fascinating paper Elite Influence on Public Opinion in an Informed Electorate, American Political Science Review 105, 496-515 (2011) by my colleague John Bullock over in the Yale political science dep't.
The principal finding of the studies reported on in the article is that members of the public who identify themsleves as Demcorats and Republicans (it is important to recognize that 30% or so do not; they are independents or others) are guided less by partisan cues (in the form of the positions of elite with recognizable partisan identities) than they are by policy substance when considering new policy proposals. This is contrary the usual account of mass opinion found in political science.
But to me, at least, the most interesting finding was one relating to "need for cognition" (NFC), a measure of the individual dispositon to engage in open-minded and effortful engagement with information. The idea that partisan cues guide opinion predicts that cues will be even more important for low NFC individuals, who tend to use heuristic reasoning (System 1 in Kahneman terms), than than they are for high NFC ones, who can be expected to use systematic reasoning (Kahneman's system 2). Bullock found this pattern in Democrats -- that is, the ones who were high in NFC paid even more attention to policy content and less to cues than Democrats who were low in NFC. But he found the opposite for Republicans: ones who were high in NFC paid more attention to cues and less to policy content. This was totally unexpected by Bullock, who, in line with his hypothesis that reliance on cues was overstated, expected NFC not to matter very much (it didn't at all, but only if one ignored the interaction with party).
What sort of (admittedly post hoc) interpretation might we place on this finding? Some might see it as supporting the position that ideologically motivated reasoning is more characteristic of conservatives than liberals. John Jost advances this argument in many papers, and Chris Mooney apparently argues for it in his forthcoming book, which I'm eager to read. Democrats, on this view, are thinking things through, Republicans reflexively adhering to ideological cues.
I don't find the "motivated reasoning asymmetry thesis" convincing. It seems to me that the balance of the evidence on politically motivated reasoning (including our own work on cultural cognition; see, e.g. "Saw a Protest") suggests that the tendency to fit perceptions of fact to one's ideological predispositions is pretty much uniform across the political spectrum (or in our work, cultural spectra).
Bullock's finding -- as truly fascinating as it is -- is in fact ambiguous in this regard. It does seem that high NFC Democrats are paying more attention to information content than high NFC Republicans, who are focusing instead on cues. But it is question begging (or in the case of the asymmetry thesis, conclusion assuming) to think that Republicans are thus displaying motivated reasoning. Indeed, since the ones in question are high in NFC, why imagine that the Republican study subjects are processing information heuristically--or unconsciously fitting their positions to cues or anything else--when they go with the partisan elite's position? It is possible that both the high NFC Democrats and the high NFC Republicans are both using systematic (conscious, high-effort information processing) -- but for different ends. Democrats might be interested in trying to figure out what information fits their values best, in which case those with high NFC would turn their attention to information content rather than being guided (consciously or unconsciously) by partisan cues. Republicans, in contrast, might value taking the position that expressed their identity or advances their group ends more, in which case those high in NFC would consciously view the position of party elites as the more important piece of information.
It is true that Republicans would be "more partisan" on this account (one could also say Democrats are more "ideological" in some sense -- that is, more focused on advancing their values than on promoting the cause of their party). Maybe some would think that is an unattractive thing (I'm not sure; I think ideological zealotry can also be worrying in many contexts).
But the point is that one could not, on this account, say Republicans are more prone to motivated reasoning. We can't say because we don't know what they (or the Democrats) are trying to get out of the information here.
This point generalizes: it is impossible to say anything about the quality of cognition that individuals display unless one knows what they are trying to accomplish. Too often in psychology, individuals who are using heuristic processing or even motivated systematic reasoning are viewed as irrational when in fact those forms of information processing are reliably advancing their interest in adopting stances that express their group identities. This is the main point of our paper on the "tragedy of the risk perceptions commons" and political conflict over climate change.
In any case, I hope Bullock is motivated (consciously or otherwise) to investigate further.