Exactly why so many Americans seem to hold the right mix of belief and paranoia required to buy into conspiracy theories isn’t quite clear, though the study did identify certain types of people who are more or less likely to hold such beliefs.

Conspiracy theories

The findings are based on survey answers from 1,511 Americans ages 18 and over who took part in the National Survey of Fears – Wave 3. The surveys were weighted to provide demographically representative results based on the American population as a whole.

Results showed that a solid minority of people who not only believed in conspiracies involving the 9/11 attacks, but also held conspiracy theories about President Obama’s birth certificate and the origin of the AIDS virus. Nearly a fourth found something suspicious in the death of Supreme Court Justice Antonin Scalia.

Here’s the breakdown:

The government is concealing what they know about …

The 9/11 attacks: 54.3 percent agree or strongly agree

The JFK assassination: 49.6 percent

Alien encounters: 42.6 percent

Global warming: 42.1 percent

Plans for a one-world government: 32.9 percent

Obama’s birth certificate: 30.2 percent

The origin of the AIDS virus: 30.1 percent

The death of Supreme Court Justice Antonin Scalia: 27.8 percent

The moon landing: 24.2 percent

Who believes?

Past research into the math behind conspiracy theories has found that the more people who are involved in keeping a plot secret, the higher the odds it will be unmasked eventually.

People who believe conspiracy theories tended to be more pessimistic, less trusting of people they know, and more likely to do things like buying a gun out of fear, the survey results indicated.

Based on the survey results, the person likeliest to have a conspiratorial mindset is a white, employed Republican with a lower income, who is affiliated with a Christian denomination but doesn’t attend religious services too often.

“Conspiracy theorists tend to be more pessimistic about the near future, fearful of government, less trusting of other people in their lives and more likely to engage in actions due to their fears, such as purchasing a gun,” Bader said.

This suspicion of government and conspiracy theories does not correspond with skepticism about everything. For instance, more than two-thirds of Americans, regardless of conspiracy-theory attitudes, held some belief in the paranormal.

Original article on Live Science.