Once you start looking for them, you find conspiracy theories everywhere. And some last for a long time.

For example, who killed JFK? Was he shot by a lone gunman, or was there a larger conspiracy?

The 50th anniversary of the Kennedy assassination is coming up this autumn—but questions still remained unanswered for many. In a 2013 AP-GfK poll, almost 6 of 10 Americans (59%) think that “multiple people were involved in a conspiracy to kill the president.” Over the years, other investigations, official and private, have disputed the conclusion of the Warren Commission that only one person was involved.

Or consider this question: Do you think that there’s a “secretive power elite with a globalist agenda” that is conspiring to rule the world? Over a quarter of American voters (28%) do, according to a 2013 survey by Public Policy Polling.

This potpourri of paranoia goes on and on: Is the National Security Administration (NSA) collecting data for purposes other than the investigation and prevention of terrorism? Seven of ten Americans think so, according to a 2013 Pew Research Center poll.

Is the government hiding facts about the tragic shootings at Sandy Hook Elementary School? A fourth of Americans (25%) believe that facts about this shooting are being hidden from view; an additional 11% say they aren’t sure, according to a 2013 Fairleigh Dickinson University’s Public Mind Poll.

So, what’s your conclusion about the JFK assassination?

Do you agree or disagree with any of the theories listed above?

Why do conspiracy theories exist?

More on that tomorrow, when we reflect on the week and consider what may be driving conspiracy thinking.