Great tips I found on the web:
Two common (and related) errors are to suppose: (1) that the stronger and more vivid is our feeling or experience of recollection, the more likely the recollection is to be accurate; and (2) that the more confident another person is in their recollection, the more likely their recollection is to be accurate.
• Memories are fluid and malleable, being constantly rewritten whenever they are retrieved. External information can intrude into a witness’s memory, as can his or her own thoughts and beliefs, and both can cause dramatic changes in recollection. Events can come to be recalled as memories which did not happen at all or which happened to someone else.
• Memory is especially unreliable when it comes to recalling past beliefs. Our memories of past beliefs are revised to make them more consistent with our present beliefs. Studies have also shown that memory is particularly vulnerable to interference and alteration when a person is presented with new information or suggestions about an event in circumstances where his or her memory of it is already weak due to the passage of time.
• The process of litigation subjects the memory to powerful biases. Parties often have a stake, and the process of preparing a statement or preparing for court can interfere with recollection.
• In litigation a witness is asked to make a statement, often when a long time has already elapsed since the relevant events. The statement is usually drafted for the witness by a lawyer who is conscious of what the witness does nor does not say. The statement is made after the witness’s memory has been “refreshed” by reading documents. The documents considered often include statements of case and other argumentative material as well as documents which the witness did not see at the time or which came into existence after the events which he or she is being asked to recall. The statement may go through several iterations before it is finalised. Then, usually months later, the witness will be asked to re-read his or her statement and review documents again before giving evidence in court. The effect of this process is to establish in the mind of the witness the matters recorded in his or her own statement and other written material, whether they be true or false, and to cause the witness’s memory of events to be based increasingly on this material and later interpretations of it rather than on the original experience of the events.
• Challenging witnesses in cross examination as to whether they are aware of the difference between recollection and reconstruction mistakenly presupposes a clear distinction, and ignores that the processes are largely unconscious and that the strength, vividness and apparent authenticity of memories is not a reliable measure of their truth.
As a result the Court concluded that in dealing with witness statements the way to proceed is to place little if any reliance at all on witnesses’ recollections of what was said in meetings and conversations, and to base factual findings on inferences drawn from the documentary evidence and known or probable facts. The greatest utility of witness statements is the opportunity cross-examination affords to subject the documentary record to critical scrutiny and to gauge the personality, motivations and working practices of a witness, rather than their mere recollection. Just because a witness has confidence in his or her recollection and is honest, it does not mean the evidence is reliable.
The judge also noted that subsequent cases after Gestmin have identified that memory is made fallible by the three distinct stages of memory:
1. When memories are remembered (encoded), what is remembered is driven by what a person sees as important, what they already have stored in memory, their expectations, needs and emotional state;
2. When stored, new memories are combined with existing fallible memories to create an overall picture; and
3. When memories are retrieved, what is recalled depends on who we are talking to and why. What we remember is constructed from whatever remains in memory following any forgetting or interference from new experiences that may have occurred across the interval between storing and retrieving a particular experience (ie. the effect of the intermingling at 2).
In addition, the Courts have followed studies which show that when new information is encoded which is related to the self, subsequent memory for that information is improved compared with the encoding of other information. There is also a powerful tendency for people to remember past events concerning themselves in a self-enhancing light.