Other people's memories contaminate ours

A study performed in Australia has found that sharing memories of the same event can create false memories when people perceive the same event differently. And, such intermingling of memories can make it very difficult to distinguish between accurate and inaccurate memories.

Dr. Helen Paterson, a lecturer in Forensic Psychology in the School of Psychology at the University of Sydney in Australia, is the lead researcher in the study.

In the August 9, 2010 press release “Sydney study finds false memories are common” from the University of Sydney, Dr. Paterson states, "A false memory is the recollection of an event, or details of an event, that did not actually occur.”

She adds, "My research focuses on how people can contaminate each other's memories for an event by discussing it with one another." [University of Sydney]

Dr. Paterson and her team focused on what happens when a person has a specific memory of an event and what happens with that memory when that information is discussed with another person who also observed that same event.

Specifically, Dr. Paterson's team used a video of a burglary of a home on test participants. Unknown to the participants, two versions of the video were used.

Afterwards, the participants discussed the video among themselves. The majority of the participants reported specific details that were not in the version they observed.
The researchers found that the discussion can lead to “memory distortion.”

Dr. Paterson explains what happened, "That is, witnesses who discuss an event with a co-witness are very likely to incorporate misinformation presented by the co-witness into their own memory for the event.” [University of Sydney]

And, "Once their memory has been contaminated in this way, the witness is often unable to distinguish between the accurate and inaccurate memories.” [University of Sydney]

The study also found that discussions with co-witnesses are more damaging to the retention of accurate memories that other avenues, such as inaccurate media reports read by the witnesses or leading questions by investigators onto the witnesses.

Paterson’s team also found that the inaccurate memories are kept even when people are told that the information communicated to them by others is wrong.

Dr. Paterson states, "This suggests to us that people sometimes find it difficult, if not impossible, to distinguish between genuine memories and false memories of an event." [University of Sydney]

Paterson makes the important point that such a situation is especially important when witnesses observe incidents that are investigated by police and law enforcement officials.

She states, "Legal procedures are designed to counter dangers which arise when civilian witnesses discuss an event with one another.” [University of Sydney]

"For example, our research has revealed that police officers in Australia often attempt to separate co-witnesses and discourage them from talking about the event with one another. Furthermore, witnesses are often prohibited from hearing each other's testimonies and lawyers may question witnesses regarding whether or not they have discussed the incident with others.” [University of Sydney]

She adds, "Despite these attempts to keep witness testimony independent, it is clear that witnesses often do talk to each other about the event. Discussion among witnesses is difficult, if not impossible to prevent." [University of Sydney]
Dr. Paterson also said discussions between co-witnesses were found to have more affect on a person's memory than exposure to inaccurate media reports or leading questioning.

And once a false memory was implanted, it could be very difficult to shake.

She adds, "Once their memory has been contaminated in this way, the witness is often unable to distinguish between accurate and inaccurate memories." [University of Sydney]

Paterson emphasizes that her research makes it very important for the police and the legal system, especially the court of law, to discourage discussions among co-witnesses in a police investigation and during a legal proceeding.

via iTWire Science News