False memories are dangerous and can be reversed, says study

London: A team of researchers has found that rich false memories of autobiographical events can be planted -- and then reversed.

The study, published in the journal Proceedings of National Academy of Sciences, highlights techniques that can correct false recollections without damaging true memories.

According to Hartmut Blank from the University of Portsmouth, "believing, or even remembering something that never happened may have severe consequences".

In police interrogations or legal proceedings, for instance, it may lead to false confessions or false allegations, and it would be highly desirable, therefore, to reduce the risk of false memories in such settings.

"In this study, we made an important step in this direction by identifying interview techniques that can empower people to retract their false memories," said Blank.

For the study, the researchers recruited 52 participants for a study on 'childhood memories' and with the help of parents, implanted two false negative memories that definitely didn't happen, but were plausible. For example, getting lost, running away or being involved in a car accident.

Along with two true events, which had actually happened, participants were persuaded by their parents that all four events were part of their autobiographical memory.

The participants were then asked to recall each event in multiple interview sessions. By the third session, most believed the false events had happened and - similar to previous research - about 40 per cent had developed actual false memories of them.

The researchers then attempted to undo the false memories by using two strategies.

The first involved reminding participants that memories may not always be based on people's own experience, but also on other sources such as a photograph or a family member's narrative. They were then asked about the source of each of the four events.

The second strategy involved explaining to them that being asked to repeatedly recall something can elicit false memories. They were asked to revisit their event memories with this in mind.

The result showed 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. Moreover, and importantly, this did not affect their ability to remember true events".