That was the question on many people's minds at the 2009 Science, Technology and Research Symposium at the Charleston Marriott Town Center after they participated in a devious experiment by economist and professional debunker of the paranormal Michael Shermer.

The setup was simple enough: Shermer played a video of six young people passing basketballs, three of them in white shirts and three in black shirts. He asked the crowd to count how many times the three in white shirts passed the basketball to each other.

Afterward, Shermer had the crowd call out answers. Then he played the video again, telling everyone just to relax and not worry about counting passes this time. And to the amazement of many, about halfway through a person in a monkey suit walked from out-of-frame into the middle of the scene, paused, gave a friendly wave and then promptly walked off screen.

It was the same video. The crowd had been so focused on counting passes that many of them missed the scene playing out before their eyes.

Shermer's trick illustrated how easily the senses could be fooled. And he said that is a large reason why belief in the paranormal, from alien abductions to spoon-bending psychics, is so common.

"We already know that people lie; that happens all the time. ... The more interesting question is why do people fall for it," he said.

Shermer, a resident of California, is a best-selling author and the founding publisher of Skeptic magazine. He is the author of "Why People Believe Weird Things," "Why Darwin Matters" and "The Mind of the Market," the latter a look at why irrational behavior drives so many economic decisions.

His focus at the StaR symposium was why people are gullible and believe in things such as UFOs, ghosts, ESP, alternative medicine and psychic powers even though no evidence exists proving they are real, he said.

At first glance, Shermer might have appeared to be preaching to the choir given that the StaR symposium brings together scientists and science students from across the state, but the skeptic said he has found scientists particularly susceptible to deception when testing paranormal claims. They are not trained in the art of the deception and are so meticulous in setting up controlled conditions for experiments that they have a hard time seeing how others can find flaws in those conditions and exploit them.

That's not saying that science hasn't found rational explanations to many paranormal claims. He noted research into sleep paralysis and the livid dreams it produces has explained why many people report alien abductions. So-called "near-death experiences" have been linked to hallucinations caused by oxygen starvation of the brain.

Shermer said he once had an out-of-body experience successfully recreated under laboratory conditions. It had nothing to do with his consciousness actually leaving his body.

The skeptic isn't familiar with West Virginia's most famous paranormal resident, Mothman, but he is with Bigfoot. He noted that no trained biologist can name a new species without producing a body. So far no Bigfoot hunters have turned up a scrap of evidence the creature exists.

As for the reason people believe strange things, Shermer said it is rooted in humanity's evolutionary history and its psychological drive to connect invisible causes to the events around them. That movement in the grass may be the wind or it could be a predator.

In evolutionary terms, it makes more sense to assume it's a predator. In other words, it's better to be safe than sorry, and therefore people are hardwired to assume there is an agent controlling the forces around them.