Lizard people control public opinion research

As reported by Atlantic Monthly, 12 million Americans believe that lizard people run our country.  This finding is based on the survey question:  "Do you believe that shape-shifting reptilian people control our world by taking on human form and gaining political power to manipulate our societies, or not?"  As a friend put it, someone went to graduate school to learn to write that question.  

The lizard people finding is a variation on findings reported in David Hemenway's article "the myth of millions of self-defense gun uses", where he reports that about 4% of people report having personally met an alien from outer space.  Even in a nationally representative sample chosen perfectly, small measurement error can be magnified when extrapolated to the nation.

The different conspiracy theories vary in prevalence, from the 4% believing in the lizard people to 51% believing that JFK was killed by a conspiracy, so clearly they are not all due to random error.  

Some of the questions are obscure or old, such as about the government controlling minds with TV (15%), the CIA invented crack cocaine (14%), and fluoride in water is dangerous (9%), which could be from non-attitudes: poll respondents' expressing opinions about matters that they have no opinion about.  Pollsters didn't understand why respondents showed different levels of support for specific issues in repeated polling.  To test whether respondents were reporting opinions about issues that they didn't truly care about, they asked respondents about a fictional bill, and 30% of respondents gave an opinion about it rather than stating no opinion.  The phenomenon was called non-attitudes.

An issue where I'm not aware of research is how non-attitudes change with time due to exposure.  If the lizard people issue gets reported widely, it could gain more exposure and credibility, and more people may endorse the statement in the future.  Can public opinion polling change opinions and give credibility to fringe opinions? 

(After some googling, I discovered that the lizard people theory is not new: it was promulgated in 1999 by a former BBC sports reporter who also included ideas about how the Jews caused 9/11 and control the media, variations on the oldest conspiracy theory around.  And Wired reported it in 2007 in a list of conspiracy theories.) 

The question on the list with the most additional poll data is probably global warming:  37% in this poll said it's a hoax (the exact question was "Do you believe global warming is a hoax, or not?")  That seems on the high side.  Gallup polls has found that 15% say that global warming will never happen, but 40% of people say that the importance of global warming has been exaggerated, which fits in with dozens of other polls.  The word "hoax" is strong and implies that global warming won't happen, and yet the percent endorsing the question is more similar to the 40% on Gallup's question about whether the importance has been exaggerated, rather than the 15% saying that it will never happen.

Context effects could have increased the prevalence of extreme opinions:  when the survey is entirely made up of kooky questions with extreme wording ("hoax" versus "exaggerated"), people may be more likely to give kooky or extreme answers.  If just one of these questions had been included on an otherwise straight-up opinion poll, a lower percentage may have endorsed it.  So maybe 4% belief in the the lizard people isn't so high, after all.