On the flip side, a 2015 study found that if there is some incentive for telling the truth, people are more likely to tell the truth. From the abstract of "Part

On the flip side, a 2015 study found that if there is some incentive for telling the truth, people are more likely to tell the truth. From the abstract of "Partisan Bias in Factual Beliefs about Politics", Quarterly Journal of Political Science Dec 2015 ( http://www.nowpublishers.com/article/Details/QJPS-14074 http://www.nowpublishers.com/article/Details/QJPS-14074 ): ""The experiments show that small payments for correct and "don't know" answers sharply diminish the gap between Democrats and Republicans in responses to "partisan" factual questions. Our conclusion is that the apparent gulf in factual beliefs between members of different parties may be more illusory than real. The experiments also bolster and extend a major finding about political knowledge in America: we show (as others have) that Americans know little about politics, but we also show that they often recognize their own lack of knowledge."" (I should note that I have not actually read this paper, only news articles purporting to describe it.)