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.