Private Investigation Services - LKA Group

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Memory Contamination

Erroneous information can be conveyed by persons in interviews about their actions, intentions or peripheral matters; not necessarily because of deliberate lying, rather false information due to faulty memory. These simple facts demonstrates that there is complexity in interviewing and showcases a problem caused by the post-event contamination of memory.

Post-event information is an important and relevant topic as when persons experience a particular event they are sometimes exposed to new information after the event has occurred which can distort their memory. The exposure to this misleading information can contribute to errors within the expressed version of events; even when the person is trying to accurately present their account.

Importantly, post-event information can supplement an interviewee’s memory or can alter the memory in some way. Often this can occur sub-consciously without awareness of its influence.

When are interviewees prone to being influenced by misinformation? In response, as time post-event increases, memories can fade and individuals can become vulnerable to the influence of misinformation and a higher likelihood that some portion of the misinformation will be incorporated into the version of events.

Another relevant question is an assessment of whether particular types of individuals are susceptible to the damaging effects of misinformation on the recollection of events? In response, research has found that children and the elderly are particularly susceptible. In addition, individuals who have dissociative experiences are also more susceptible. These can be particularly relevant for the investigation of motor incidents; for instance, the dissociation experience of an individual driving to a location and suddenly realising that they have no memory of what has happened on all or part of the trip. This could include no awareness as to actions actually performed or a mere thought of performing such an action. People who distrust their own memories have been found to be susceptible to developing false or partially false memories of particular events.

Whilst this article does not intend to cover all examples, investigators should be mindful that temporary states of hypnosis can also lead to misinformation and persons with low cognitive ability are known to be more susceptible to the damaging effects of misinformation.

The investigative world can be black and white; by this I mean that a witness can tell you nothing or you can have a highly cooperative witness that tells you too much. It is important to acknowledge that personality characteristics such as being high in cooperativeness can contribute to distortion of memories due to the effect of misinformation, especially so if driven by the post-event information from other sources and witnesses.

An awareness of the aforementioned phenomena is the first step; an investigator can then take active steps within the process to expose and guard against the problem of mistaken and distorted memory. These might include:

  • Recognise that people may have been exposed to new information in the post-event period. Actively look for and enquire into any exposure where new information may have supplemented or altered the interviewee’s memory.
  • Important to remember that people get information when they are exposed to the versions of others, media coverage of suggested answers in the line of questioning.
  • Look for potentially self-generated misinformation; this could be in the form of, diary notes, email correspondence or personal comments about psychotherapy influences.
  • Always remember that just because the interviewee said it happened in a particular way, just because that person expressed it with confidence and that the recollection was detailed and further that it was expressed with emotion does not mean that it is necessarily a true and accurate account.  False memories can be expressed with confidence and emotion, especially so if they have been subjected to memory distortion.
  • Look to verify a version of events from multiple independent sources.

Investigators work within difficult contextual environments as it is well known that people can lie, people tell the truth and people can think they are providing accurate versions of events, yet their recollection has been subjected to memory distortion and is therefore inaccurate or incorrect in some detail. Gathering information from a broad range of sources is important so that the set of facts, biases and differences in recall can be differentiated and valid inferences drawn. Investigators can then construct a version of events that might be closer to what actually happened than a version gathered from just one source.

LKA Group utilises broad avenues to gather information and always seeks to independently verify evidential accounts or versions of events through credible means. To achieve this aim, LKA uses intelligence driven processes which carries the flow-on effect of targeting investigative action and attention where it is most needed to reach a credible final version.

Andrew Hedges
Chief Operating Officer

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