False memories can be planted among study participants and later rooted out, according to a small new study in the Proceedings of the National Academy of Science—findings that the researchers said could provide insight on how to address misremembered recollections in other contexts, Brianna Abbott writes for the Wall Street Journal.
For the study, researchers from Germany and the United Kingdom wanted to explore what they said was a relatively unexamined area of false memory research—particularly, how to root out false recollections.
To do so, the researchers enrolled 52 study participants with an average age of 22 at the Johannes Gutenberg University of Mainz, as well as the participants' parents. The participants and their parents were told that they were involved in research on childhood memories, and both groups—parents and participants—were asked not to talk to each other about the research.
For the first part of the study, the researchers aimed to plant false memories among the study participants. To do so, they first sent the parents a questionnaire asking them whether their children had had any negative experiences, such as running away from home. They also asked parents to share two events that hadn't happened to their children, but which could have plausibly taken place.
Then, the researchers had interviewers talk with the study participants over the course of three sessions to plant these false memories. The interviewers were not made aware of which memories were true or false, nor were they aware that they were being used to plant fake memories.
During the interviews, the interviewers told the participants that their parents had shared some information about certain childhood events. Specifically, they shared with each participant four memories, including two real ones and two fake ones. For one pair of true and false memories, the researchers just offered light suggestions that the events had occurred. For the other pair, the interviews were more aggressive, pushing participants to remember the events and reflect on them between interviews.
At the end of the three interviews, study participants said they had some level of recollection about the mildly suggested false events 27% of the time. In comparison, when interviewers had pushed the events more aggressively, participants said they had some level of recollection about the false event 56% of the time. However, some people consistently rejected any suggestion of false events.
For the second part of the study, researchers tried to root out those false memories by having participants go through two more interviews. In the first interview, participants were told their memories might not be based on their own experiences but other sources, such as family narratives or pictures, and they were asked to specify the origin of each memory. For the second interview, study participants were told that being repeatedly asked to recollect events could create false memories, and they were asked to consider whether that applied to any of the events they'd discussed.
After that round of interviews, the researchers found fewer study participants believed in their false memories, although some still claimed to have richly detailed recollections. Overall, the study found participants tended to have greater confidence in their real memories, and were able to describe them in more detail, than they did their fake memories. And while their confidence in the fake memories waned after the second round of interviews, their confidence in their real memories remained fairly consistent, the study found.
According to Hartmut Blank, co-author of the research from the University of Portsmouth's Department of Psychology, the findings are valuable because they can shed light on how to combat the issue of false memories in police investigations and court proceedings, where false memories can take the form of false confessions or false allegations.
The study makes "an important step" in curbing "the risk of false memories in such settings," Blank said, "by identifying interview techniques that can empower people to retract their false memories."
Specifically, Blank said that "by raising participants' awareness of the possibility of false memories, urging them to critically reflect on their recollections, and strengthening their trust in their own perspective, we were able to significantly reduce their false memories" while preserving "their ability to remember true events."
However, other experts said while the findings affirmed prior false memory research, their real-world application may be limited, given the study's small sample size and the fact that it was conducted in a lab.
For instance, Nancy Dennis—a memory researcher and associate professor of psychology at Pennsylvania State University, who was not involved in the study—said while people tend to find their real memories stronger than any incorrect and false ones, people can also experience very vivid, rich false memories and weaker real memories, making them difficult to distinguish on an individual level.
"The hard part is when you want to take someone on that witness stand or therapists' office and want to figure out if that particular memory is true or false," she said (Abbott, Wall Street Journal, 3/22; Science Direct, 3/24).