The power of human imagination may be stronger than previously suspected, blurring the line between memory and imagination, a University of Washington psychologist reported today at the annual meeting of the American Association for the Advancement of Science.
"One simple act of imagining a fictitious childhood event increased people's confidence that the event happened to them," said Elizabeth Loftus, a UW professor of psychology, who discussed the results of a series of new studies that explored memory and imagination.
"We call this phenomenon 'imagination inflation' and the implications of the mind being so malleable are enormous."
She also pointed to a new direction in memory research, exploring whether the power of imagination can be used to aid people in adopting beneficial health habits.
Loftus, a leading memory researcher and central participant in the debate over repressed memory, was part of a news briefing panel on "Memory in a Complex World." Other panel members were Henry Roediger, chairman of the psychology department at Washington University in St. Louis, and Eric Eich, an associate professor of psychology at the University of British Columbia.
To explore what happens to human memory when people imagine events that did not occur, Loftus and other researchers conducted a series of related studies. In the initial study, subjects were given a written list of 40 possible childhood events and asked about the likelihood that these events happened to them on a scale of responses ranging from definitely did not happen to definitely did happen.
Two weeks later, the subjects were asked to imagine they had experienced some of these events, ones they had identified as not occurring. These events included falling and breaking a window with their hand, getting in trouble for calling 911, finding a $10 bill in a parking lot or being pulled out of the water by a lifeguard. Not all of the subjects were asked to imagine the same events.
In a typical one-minute exercise, subjects were told to picture it was after school and they were playing in the house when they heard a strange noise outside. They were told they ran toward the window, tripped, fell, reached out and broke a window with their hand. While imagining the situation, the subjects were asked several questions, such as what caused them to trip, what did they feel and what did they do after realizing they were cut. After imagining several situations, the subjects again were given the list of 40 childhood events to fill out.
Comparing the answers from the two lists, Loftus and her colleagues found that a one-minute act of imagination led a significant minority of subjects to say an event was more likely to have happened after previously identifying it as unlikely to have occurred. In the broken window scenario, 24 percent of the subjects who imagined the event showed an increase in confidence that the event had actually happened. For those subjects who did not imagine breaking the window, 12 percent showed a corresponding increase.
Across the eight events that some subjects were asked to imagine, the researchers found that there was more positive change in imagined scenarios, 34 percent, than in non-imagined ones, 25 percent.
Loftus said there are several possible explanations for this "imagination inflation" or why imagining an event led some people to change their minds about the likelihood of a fictitious event actually having happened. One reason might be that an act of imagination might remind some subjects of a true experience. Another and more likely explanation, she said, is that an act of imagination simply made an event more familiar when the second assessment was made and that familiarity was mistakenly related to childhood memories, rather than the act of imagination.
Several subsequent studies replicated the original findings and also found that people with memory or attention lapses are more likely to engage in imagination inflation. In addition, memory inflation also occurs when subjects imagine something happening to other people, but the effect is strongest when they imagine themselves in a situation.
"Imagination about the self leads to more distortion than imagination involving others. But there are situations, such as people sharing their experience in Veteran's Administration group therapy sessions for example, where there may be some people who tend to absorb and take in other peoples' stories as their own and believe they happened to them," Loftus said.
In a look at a new direction for her research, Loftus said "A big question for the future is can we harness the power of imagination to help people lead healthier lives."
She said this work would examine the possibility of engaging people's minds to imagine practices widely recommended by the medical community -- such as eating more fruits and vegetables or flossing your teeth twice a day -- as a technique for promoting activities and having people adopt them as habits.
Loftus' collaborators in the imagination inflation studies included Charles Manning and Marcos Nunes-Ueno, doctoral candidates in psychology at the University of Washington; Maryanne Garry, a former UW post-doctoral researcher and now assistant professor of psychology at Victoria University of Wellington, New Zealand; and John Paddock, an Atlanta clinical psychologist.