Hypnosis Creates False Confidence In Memory, Study shows

by Jeff Grabmeier

Researchers asked college students, including some who were under hypnosis, to give the dates of 20 national and international news events from the past 11 years.

Those who were hypnotized were no more accurate than others in naming the correct dates. But those who were hypnotized were more reluctant to change their answers when they were told they might be wrong.

The results suggest that people may have too much faith that hypnosis can help them accurately recover lost memories, said Ohio State University psychologist Joseph Green, co-author of the study.

"Myths and misconceptions about hypnosis abound," Green said. "While hypnosis does not enhance the reliability of memory, there is some evidence that hypnosis leads to increased confidence in memories."

These results support earlier research co-authored by Green that found nearly nine of ten people in four countries believe that hypnosis can help someone remember something that they could not remember otherwise.

About half the students were hypnotized before performing the task, while the other half performed a progressive muscle relaxation exercise.

In addition to giving dates, the students were asked to rate how confident they were in the estimates they gave. The students answered the questions and turned in their papers.

A few minutes later, the papers were returned to the students. They were told that if there was a red star on the back, it meant that one (or more) of the dates were wrong. In fact, though, the researchers had put red stars on ALL of the papers. The students were then given ten minutes to review and change any of their previous estimates and give new ratings of how confident they were in their date estimates.

Results showed that the students who were hypnotized were no more accurate than those in the relaxation group. On some of the questions, none of the students were within three months of the correct date. Nor were the hypnotized students more confident in their date estimates than were the other students, Green said. But the hypnotized students were less likely to change their answers (24.6 to 16.9 percent).

The reason may be the myths that surround hypnosis, Green said. "It's widely believed that hypnosis somehow acts as a truth serum, that it unlocks memory and permits people to perform mental operations that they otherwise couldn't do," Green said.

These myths occur worldwide, according to research Green helped conduct. In a survey of 280 students in Australia, Germany, Iran and the United States, 88 percent said hypnosis can help people remember something they couldn't otherwise remember. There were no significant differences in this belief between countries.

Green said the results of the new study don't mean that hypnosis has no value. Any kind of technique used to retrieve memories --- including the use of diaries or drugs -- will produce inaccurate memories. However, the difference is that people tend to have more faith in hypnosis than they do in other memory techniques.

The bottom line is that memories recovered through hypnosis, or any other technique, need to be corroborated through other means before they are accepted as true, he said.

Green and Steven Jay Lynn/ State University of New York presented their results Aug. 26 in San Francisco at the annual meeting of the American Psychological Association.