On Those Trump Voters Who Believe in the Bowling Green Massacre
I'm sure there is some set of individuals out there who hold an active belief that a massacre was conducted by Islamic extremists in Bowling Green. Presumably they heard it from Kellyanne Conway, and dismiss all of the media fact-checkers as promoting fake news due to their bias against Trump. But a more common thought process probably goes like this: "There have been a bunch of Islamic terrorist attacks over the last few years, which justify the president's policies. I don't happen to recall the specific details of the attack in Bowling Green, but I assume since they're asking me about it, it must be one of them. I don't want to sound stupid by saying I never heard of it. Nor do I want to have the poll come out showing weak support for the president just because I quibbled about the details of one specific attack. After all, there have been enough of these attacks to justify the policies overall, regardless of the details I've forgotten about Bowling Green. So I'll say yes."
Imagine a poll in which people were asked whether the recent police shooting of LaShawn Dyer justified efforts toward criminal justice reform. LaShawn Dyer was not in fact shot by the police -- I made him up just now. But most liberals who are sympathetic to the Black Lives Matter movement don't remember the full list of outrageous police shootings off the top of their head. So when put on the spot to answer a question about the nonexistent Mr. Dyer, they would go through a similar process to the Trump voter in the previous paragraph. They would answer yes about the specific case of LaShawn Dyer because they know there is a more general phenomenon of unjustified police shootings of black people, and they want to endorse the need for criminal justice reform.
Just because someone reports a false belief on a survey, doesn't mean that they hold that false belief. They may just be coming up with an answer to satisfy the inquiries of the pollster and keep from looking stupid, working on the assumption that the question contains meaningful and relevant information and is not a blatant attempt to trick them. This is a well-known phenomenon among psychologists, known as the issue of constructed preferences.
Consider this classic nonpartisan example. Some years ago, poll respondents were asked whether they supported Congress renewing the nonexistent 1975 Public Affairs Act. Here they don't even have the cues of being told there was a massacre or a police shooting to help them put it in context -- "Public Affairs Act" was deliberately chosen as the most banal bill name imaginable. And yet 43% of people claimed to support or oppose the PAA renewal. I think it's pretty tough to claim that those people hold clear, considered viewpoints on the PAA, that they go about their day actively believing in the existence of this made-up act. So likewise, I suspect most of the people who gave a positive response about the Bowling Green Massacre are not going around actively believing that there was such a massacre.