Can you trust your memory?

False memories, memories that you believe to be true, but have in fact never happened, have been a topic of psychological research for some time. A recent special issue of the journal Memory looked at false memories and how our brains may have a detection system for filtering out memories that it feels have been distorted.

Mmegi Online News/January 16, 2007
By Lauri Kubuitsile

Many studies have been done on false memories. In 1995, Elizabeth Loftus, a researcher at the University of Washington in the United States, conducted a study in which she used 24 subjects and tested them to find out if she could implant a false memory in their minds. After interviewing a close relative of the subject, usually a parent or a sibling, she put together a questionnaire about four events that happened in the subject's past; three of the events were true and were events that the relative of the subject had told Loftus. The fourth event was false. In all cases it was about the subject, at the age of five, being lost in a shopping mall. They were later found quite upset by an elderly relative. This event was completely fabricated but was presented to the subject as a story retold by their close relative.

In 25 percent of the subjects they believed that the event was true and had actually happened to them. They were even able to add details to the false memory. Some even when told that in fact the whole thing was false, continued to believe that the event did happen to them.

This type of false memory is called a phantom recollection. In Loftus' study, since being lost is a common story and something that may very well have happened to the subject, it is likely they tagged the relative's memory to other memories about people being lost and convinced themselves that in fact the memory was true.

In the recent issue of Memory, they looked at such processing of memories in our brains. The issue, edited by James M. Lampinen and Timothy N. Odegard of the University of Texas in the United States, featured various studies on the processing and editing of memories including false memories.

Lampinen and Odegard themselves have done research proving that although our brain does occasionally create false memories, sometimes quite detailed and vivid false memories, our brain also has some checks and balances. It appears that our brains also filter out memories that it finds might be false. This is called recollection rejection. Little research has been done about this type of memory editing, though, the two researchers believe that recollection rejection makes false memories less common than may have been believed in the past.

Memory though is a tricky business. In another recent study looking at false memories and distorted memories, Elizabeth Kensinger at Harvard University found that our memory is also affected by our emotions and our feelings about what we are witnessing. Two people looking at an event, but having opposite emotions about what they are witnessing will go away with two completely different sets of memories about it.

She studied 76 people who had attended a baseball game in 2004, the league playoff game between the Boston Red Sox and the New York Yankees in which the Red Sox won. Kensinger's study focused on personal memories, for example what they ate at the game or what clothes they were wearing, and on event details, which included memories about the game.

She found that for memories about personal details, both Yankee fans and Red Sox fans remembered things equally well, but for event details including memories about the game, the losers, the Yankees fans, had better memories of the event. What this showed was that memory distortion for event-details is affected by the person's emotions and that negative emotions seemed to enhance the person's ability to have clear, non-distorted memories.

In the special Memory issue, Lampinen and Odegard said that they hoped it "will inspire new empirical work and fresh insights into the nature of false memory creation and into the mechanisms that guard against false memories".