A new study finds support for the theory that the more sources of perceptual information people have about an event--the sight, sound, feel or taste of an experience--the more likely they are to believe they actually experienced the event, even if they haven't.
In particular, the "realness" of a false memory results from the brain's ability to pull together perceptual information from unrelated experiences and wrongly read it as a single, authentic memory. This "source monitoring" theory of false memories postulates that people misattribute perceptual information experienced in a different context to support a memory for something that never happened.
The more perceptual information people can connect to the false memory, the more likely they are to have that false memory in the first place, the study finds. In particular, Linda Henkel, PhD, and her colleagues find that study participants were more likely to falsely remember seeing an object if they previously imagined the object and heard the sound it makes.
In two separate experiments, they had more than 170 undergraduates view, imagine or listen to the sound of common, easily recognized events, such as a baby crying, a toilet flushing, a hammer hammering or a basketball bouncing. And they found that participants were much more likely to incorrectly say they saw, for example, a hammer if they previously imagined a hammer, or heard a tape of hammering, than if they had no previous exposure to anything "hammer-like." And they were even more likely to falsely remember the hammer if they visually imagined it and, at a different time, heard hammering.
The findings suggest that repeated exposure to certain objects and events through sight, sound or just imagination can muddle people's memories of where or how they experienced something or even whether their experience is real, conclude Henkel, now at the University of North Florida, and her colleagues Nancy Franklin, PhD, of the State University of New York at Stony Brook, and Marcia Johnson, PhD, of Princeton University.
"People commonly have repeated experiences with certain objects and events," says Henkel. "And what we're seeing is that similar types of memories can get confused and people can mistake one instance for another."
In fact, the most compelling false memories may be those in which fragments of real experiences--viewing photos, hearing others recount events or daydreaming--play a role, the researchers say. Their study appears in this month's issue of the Journal of Experimental Psychology: Learning, Memory and Cognition (Vol. 26, No. 2).