Denver -- Remember that wonderful day when Bugs Bunny hugged you at Disneyland? A study presented Sunday shows just how easy it can be to induce false memories in the minds of some people.
More than a third of subjects in the study recalled that theme-park moment -- impossible because Bugs is not a Disney character -- after a researcher planted the false memory.
Other research, of people who believed they were abducted by space aliens, shows that even false memories can be as intensely felt as those of real-life victims of war and other violence.
The research demonstrates that police interrogators and people investigating sexual-abuse allegations must be careful not to plant suggestions into their subjects, said University of California-Irvine psychologist Elizabeth Loftus. She presented preliminary results of recent false memory experiments Sunday at the national meeting of the American Association for the Advancement of Science.
Loftus said some people may be so suggestible that they could be convinced they were responsible for crimes they didn't commit. In interrogations, "much of what goes on -- unwittingly -- is contamination,'' she said.
The news media's power of suggestion also can leave a false impression, Loftus said.
"During the Washington sniper attacks, everyone reported seeing a white van,'' she said. "Where did it come from? The whole country was seeing white vans.''
Loftus is one of the country's most controversial memory researchers. She frequently draws harsh criticism from victims' advocates, attorneys and other scientists.
Over 25 years, she has examined more than 20,000 subjects and written 19 books. She appears frequently in court as an expert witness.
While some recovered memories turn out to be true, Loftus says her experiments repeatedly show that memories are fragile possessions that are easily manipulated. But she does not condemn her subjects for being gullible.
Of adopting false memories, she said: "This behavior is entirely normal.''
A key, researchers said, is to add elements of touch, taste, sound and smell to the story.
In the Bugs Bunny study, Loftus talked with subjects about their childhoods and asked not only whether they saw someone dressed up as the character, but also whether they hugged his furry body and stroked his velvety ears. In subsequent interviews, 36 percent of the subjects recalled the cartoon rabbit.
In another study, Loftus suggested frog-kissing incidents that 15 percent of the group later recalled.
"It is sensory details that people use to distinguish their memories,'' said Loftus. "If you imbue the story with them, you'll disrupt this memory process. It's almost a recipe to get people to remember things that aren't true.''
In other research presented Sunday, Harvard University psychologist Richard McNally tested 10 people who said they had been abducted, physically examined and sexually molested by space aliens.
Researchers tape-recorded the subjects talking about their memories. When the recordings were played back later, the purported abductees perspired and their heart rates jumped.
McNally said three of the 10 subjects showed physical reactions "at least as great'' as people suffering post traumatic stress disorder from war, crime, rape and other violent incidents.
"This underscores the power of emotional belief,'' McNally said.