It is relatively easy to trick people into believing that they experienced or observed a certain event that in reality never happened – researchers have shown this several times. A new study has now successfully achieved the opposite: After the researchers had initially provided the test subjects with false autobiographical memories through suggestive interviews, they taught them simple techniques to expose the false memories as such. This result is particularly relevant in connection with witness statements in criminal trials. So far, wrong memories have been a serious problem here.
Be it the course of an accident or our own childhood experiences: We are often convinced that we can remember certain situations precisely. The more we think about it, the more vivid and detailed the images become in our mind’s eye – and yet they can be wrong. Such bogus memories can lead to problems, especially in criminal proceedings, if witnesses are firmly convinced that they have experienced or observed something that does not necessarily correspond to reality. In numerous studies, researchers have already shown how, for example, suggestive questions can evoke such sham memories. A solution to the problem, however, has so far been less of a focus.
Wrong childhood memories
A team led by Aileen Oeberst from the FernUniversität Hagen has now dealt with this. “While several studies have succeeded in inducing false memories in interview settings, we present studies that attempt to reverse this effect,” the authors say. To this end, they too initially triggered false memories in their test subjects. In order to create the most realistic scenario possible, Oeberst’s team asked the parents of the test subjects in advance to name several negative childhood memories of the test subjects – for example the experience of getting lost, being involved in an accident or being the perpetrator or victim of property damage. In addition, the parents should name two incidents that would be plausible but did not occur.
In three suggestive interviews, the subjects were asked about two actual and two alleged events in their childhood. In order to rule out distortions, the interviewer himself did not know which of the events were true and which were false. After each interview, the researchers tested how much the subjects believed they remembered the respective events. “The quality of memories was generally higher when they related to true events,” report the researchers. “In the course of the interviews, however, the quality of false memories increased significantly.”
Where does the memory come from?
With strong suggestion in the interviews, the researchers succeeded in actually getting 56 percent of the test subjects to believe that an invented event was a memory of their own. In the case of subjects who were only interviewed in a slightly suggestive way, the figure was 27 percent. In the following, the researchers gave all test subjects two strategies for discovering false memories. On the one hand, they encouraged the test subjects to think about the sources to which their memories go back: Are they really their own experiences, or could they be family photos, parents’ stories or other external reports? This step already reduced the proportion of test persons who believed they could really remember the alleged experiences.
On the other hand, they made the test subjects familiar with the concept of bogus memories – but did not reveal to them that they themselves had put such bogus memories on them in the experiment. After both interventions, the memory quality of the false memories decreased in all test subjects and only 23 percent of the test subjects who were exposed to strong suggestions thought the alleged experiences were their own memories. For the subjects with weakly suggestive interviews, it was 15 percent.
Little impact on real memories
The comparison with the quality of real memories showed that the effect was not due to the subjects generally becoming more skeptical about their own memories. Although the two interventions also reduced the quality of the real memories slightly, they were much weaker than with the false memories. “If the subjects are asked to consider the possibility of false memories, this apparently helps to interrupt a previous confirmatory mindset in which they were trying to recall memories that ‘have to be there’,” the researchers write.
The advantage of the two methods tested is that the user does not have to know whether a memory is actually true or false. This is particularly important in criminal proceedings, as the objective truth is usually not known. It is still unclear to what extent the techniques work equally well when the false memories are anchored more deeply in the subject’s memory or self-image than was possible within the scope of the experiment. “Our study shows, however, that it is in principle possible to undo false memories, which offers a promising outlook for both future research and practice,” the researchers said.
Source: Aileen Oeberst (FernUniversität Hagen, Germany) et al., Proceedings of the National Academy of Sciences, doi: 10.1073 / pnas.2026447118