Study Finds Memories Can Change with Each Recall; Researcher Sees Criminal Justice Implications
A Northwestern University researcher has found that memory retrieval may be like the game of telephone.
Just as a whispered message changes with each retelling, memories can change when they are recalled multiple times, according to the study by Donna Bridge, a postdoctoral fellow at Northwestern University Feinberg School of Medicine. A press release summarizes the findings published in the journal Neuroscience.
“A memory is not simply an image produced by time traveling back to the original event—it can be an image that is somewhat distorted because of the prior times you remembered it,” Bridge said in the press release. “Your memory of an event can grow less precise even to the point of being totally false with each retrieval.”
Bridge says her findings have implications for eyewitness accounts in criminal trials. “Maybe a witness remembers something fairly accurately the first time because his memories aren’t that distorted,” she said. “After that it keeps going downhill.”
Test subjects in Bridge’s study were asked to recall the location of objects on a grid in three sessions on three consecutive days. On the second day, the subjects were shown a subset on the first day’s objects and asked to move them to their original locations. On day three, the test subjects showed greater recall of the objects they manipulated on day two. But when test subjects made a mistake on day two, they were more likely to repeat the mistake on day three by placing the object closer to the incorrect than the correct location.
The Neuroscience study used 12 subjects, but Bridge has repeated the results. “When someone tells me they are sure they remember exactly the way something happened, I just laugh,” Bridge said in the press release.