Researchers at Harvard University called on aliens from outer space to help them solve a problem that surfaces frequently in everything from therapeutic sessions to criminal trials, or even just chatting with a friend.
How do you know if someone is telling the truth when he or she recalls memories of childhood abuse, or being raped by satanic cults, or some other traumatic insult?
One clue that many of us rely on is the emotional reaction of the person telling the story. If the victim breaks out in sweat and becomes extremely emotional while recalling those memories, it's more difficult to dismiss them as false.
But all that really means is the person truly believes his or her memories are true, not that they really are, according to the researchers.
"The person really believes something happened," says Richard McNally, a clinical psychologist and professor of psychology at Harvard, lead author of a study in the July issue of Psychological Science. "But that doesn't necessarily mean it did."
True or False?
Deciding which memories are true, and which are false, is a real tough problem for therapists and law enforcement officials, and sometimes friends. That's especially true when long-buried memories suddenly surface involving traumatic events that may have occurred years ago. McNally has struggled with the problem for years, moving from combat traumas to memories of childhood sexual abuse.
He says that even a seasoned therapist can be influenced by the emotional state of the person recalling the memories.
"A therapist is more inclined to credit the account as authentic if it's accompanied by really intense emotion," he says. "The therapist thinks 'my goodness, something must have happened.' "
Years of research have convinced him that even false memories can stimulate a lot of emotion, but how do you prove that in the lab? That's where the aliens from space come in.
If someone claims to have been sexually abused years ago, it's almost impossible to prove those memories false. What the researchers needed was a group of people who sincerely believed memories of something that clearly never happened.
So they put an ad in newspapers asking for people who had been abducted by aliens from space.
Emotions Cloud Truth
They got a lot of weird phone calls, including some from people claiming to be aliens, but in time they had their subjects, six women and four men who believed they had been abducted by alien beings. Their average age was 47. Seven women and five men who had not been abducted also participated in the study.
The "abductees," as they came to be known, were interviewed and recorded as they told brief stories about their abduction, as well as other stressful, happy and neutral tales. All of the participants were wired so the researchers could monitor for heart rate, sweat production, and facial muscle tension, three strong indicators of emotional stress.
The emotional reaction among the abductees soared while listening to the stories of stress and abductions. But it was much weaker while listening to happy or neutral narratives.
The 12 participants who had never been abducted barely responded to any of the stories.
The verdict was clear, McNally says. The emotional reaction, which can be so convincing, had nothing to do with the veracity of the memories of the folks who believed they had been abducted.
Why did they believe so strongly in something that is so implausible? In answers to a questionnaire, the abductees scored high on personality traits that make them a bit different. For example, just because an idea seems magical doesn't necessarily mean it isn't true.
People with those traits tend to have "a rich fantasy life, and to endorse unconventional beliefs," the researchers say in their report.
And the stories they told were anything but conventional, yet they had much in common, McNally says.
"I would ask them, how did this all begin," McNally says. "And they would typically say 'I was lying in bed one night, and a few hours before dawn I suddenly woke up. I tried to move over and I realized I was completely paralyzed. It was absolutely terrifying. I felt electrical sensations coursing through my body, I heard humming noises, I saw lights flashing, and I felt myself levitating off my bed when suddenly I saw these strange beings, these strange figures coming up towards the bed. And then I blanked out. Later, I woke up and had no idea what had happened.' "
Some time later, McNally says, while in therapy, the memories came back.
"'I was taken up into a spaceship, medically probed, met alien beings, met my hybrid children,' " the participants told him. They frequently said they had sex with the aliens.
To the abductees, that meant they were something special.
All described the abduction as terrifying, but when McNally asked them if they wished it had never happened, they all said it was worth it. The abduction proved there were other beings out there who cared for us, and for our planet, and even wanted to mate with humans to ensure continued survival of life on Earth.
"Their experience with these alien beings ultimately becomes sort of a spiritually deepening one for them," McNally says.
Most of the participants came from traditional religious backgrounds, but had drifted away.
"These individuals have strong spiritual needs that are not being met by conventional religions," McNally suggests.
Whatever the cause, the research shows clearly that to these people, the memories are real, even though it's safe to say the events never happened. But there's no point in trying to convince them.
Even if he could explain to them exactly why they thought all this happened, and show convincing reasons why the memories are false, "I strongly suspect they would not buy it," he says.
"A naturalistic explanation robs the universe of its magic," he says.
Lee Dye’s column appears weekly on ABCNEWS.com. A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska.