Subsequent research found that correcting these kinds of errors actually made the situation worse. Brendan Nyhan of Dartmouth and Jason Reifler of Georgia State found that Republicans presented with news articles pointing out that there were no WMDs in Iraq were more likely to say that such weapons were found than Republicans who didn't read those articles. The truth, in other words, triggered a partisan backlash.
One way to interpret these results is as a worrying sign of epistemic closure. Democrats and Republicans, the theory goes, are increasingly cloistered in their own media cocoons and refuse to accept facts that don't comport with what they already believe.
But there's always been a question about how serious the respondents in these studies are. Maybe the Republicans in the Nyhan-Reifler study knew that there weren't any WMDs, but they wanted to signal support for the war in Iraq and President George W. Bush, and so answered incorrectly. Answering incorrectly, under this view, is just a way to register an opinion in the survey, not an expression of what the survey respondent actually believes. Partisans aren't closed off from reality, by this theory. They're just lying.
Political scientists John Bullock, Alan Gerber, Gregory Huber (all at Yale) and Seth Hill (at UC-San Diego) have a new paper that presents strong evidence for the they're-just-liars theory.
They ran two experiments. In the first, they split respondents into two groups: Those in the control group were asked basic factual questions about politics; those in the treatment group were asked the same questions but were entered into a raffle for an Amazon gift card wherein their chances depended on how many questions they got right.
In the control group, the authors find what Bartels, Nyhan and Reifler found: There are big partisan gaps in the accuracy of responses. On every question but one on whether the deficit rose under George W. Bush, there were statistically significant differences in Republicans and Democrats' responses. For example, Republicans were likelier than Democrats to correctly state that U.S. casualties in Iraq fell from 2007 to 2008, and Democrats were likelier than Republicans to correctly state that unemployment and inflation rose under Bush's presidency.
But when there was money on the line, the size of the gaps shrank by 55 percent. The researchers ran another experiment, in which they increased the odds of winning for those who answered the questions correctly but also offered a smaller reward to those who answered "don't know" rather than answering falsely. The partisan gaps narrowed by 80 percent.
Take unemployment: Without any money involved, Democrats' estimates of the change in unemployment under Bush were about 0.9 points higher than Republicans' estimates. But when correct answers were rewarded, that gap shrank to 0.4 points. When correct answers and "don't knows" were rewarded, it shrank to 0.2 points.
The authors conclude that false answers — like Democrats saying that casualties in Iraq increased from 2007 to 2008 — are just cheap talk, a way to signal a party affiliation rather than a sincere belief.
"Persistent partisan gaps, if sincere, suggest important limitations to democratic accountability. If Democrats and Republicans perceive different realities, then the incentives for incumbent politicians to pursue policies that generate objectively good policies may be reduced," they write. "Our results imply that such concerns are overstated. Democrats and Republicans may diverge in their survey reports of facts, but such responses should not be taken at face value as sincere expressions of partisan worldviews."
This is just one study, and I suspect it will prompt similar research. But it does suggest that Democrats and Republicans don't inhabit totally different worlds. Maybe they just don't take survey questions very seriously.