False memories easily implanted
LIKE A CONCEPT FROM the movie Inception, Australian scientists have found that memories can be altered by suggestion from other people.
A University of Sydney study has shown that memories of an event can be amended or added to if people discuss their recollections with another witness. The findings have implications for the way police conduct interviews.
“People sometimes find it difficult, if not impossible, to distinguish between genuine memories and false memories of an event,” says lead researcher and forensic psychologist Helen Paterson.
The study tested the ‘memory conformity’ of 64 undergraduate students by showing them one of two versions of a supposed house burglary. The researchers found that after discussing the video with another witness, most participants reported remembering specific details that were not in the version they were shown, and they would continue to ‘remember’ even when warned they were being fed misinformation.
Memory is a reconstruction
“Once their memory has been contaminated in this way, the witness is
often unable to distinguish between accurate and inaccurate memories,”
Helen says. The study found that this phenomenon, known as a false or
suggested memory, is widespread and mostly unconscious. “We are used to
having discrepancies in our memory, so most people have no idea that
[false memories] are there,” Helen explains.
Professor Kevin McConkey a psychologist from the University of Newcastle says that autobiographical memory – the form of memory used in recollecting events – is inevitably inaccurate. “When we remember something, it’s a reconstruction of events. And like any reconstruction, it’s a mixture of actual and subsequent memories filtered through our beliefs.”
Kevin says that memory is also influenced by the recollections of others, and the relative confidence with which these are held.
Impact on the justice system
While discussion between witnesses is difficult, if not impossible, to prevent, Helen says police and legal authorities are aware of the potential impact on the justice system and the need to separate witnesses and avoid the use of leading questions when gathering testimony.
A recent policing initiative in the United Kingdom has begun introducing so-called self-administered interviews, in which witnesses are asked to write down their own account of what they have seen, shortly after the event has occurred. These interviews are intended to prevent cross contamination caused by discussions between people.
Helen underscores the importance of avoiding cross contamination by saying that discussions between co-witnesses were found to have more affect on a person’s memory than exposure to inaccurate media reports or leading questioning. “When you have five people giving almost identical evidence, it can look compelling, although it may not be,” she says.
The study is published online in the journal Applied Cognitive Psychology.
