This post originally appeared on the excellent Civil Litigation Brief blog and is reproduced here thanks to the kind Mr Gordan Exall saying it's ok. Thanks Gordon! If you enjoy the blog below you may also wish to read this speech by Mostyn J on a similar theme from 2014, which Gordon also wrote about here.
WHERE DOES THE TRUTH LIE? GESTMIN IN THE FAMILY COURTS
This blog has looked at the “Gestmin” guidance many times. I am grateful to Lucy Reed for pointing out that it has been considered in the context of family law. In Lachaux -v- Lachaux  EWHC 385 (Fam) Mr Justice Mostyn considered the guidance in relation to issues between (it transpired) former husband and wife. (When the case was being discussed on Twitter one counsel observed that in a recent case the judge had brought copies of the Gestmin judgment to court to give to the advocates. This, the judge, stated should help concentrate minds on the relevant issues in cross-examination.)
This is another case that highlights the importance of the Gestmin guidance in relation to disputed witness evidence. These are principles that are universally applied and a detailed knowledge of them is an essential part of the litigator’s tool kit.
“I share the misgivings of Leggatt J in placing weighty reliance on carefully prepared “remembered” accounts of past events as expressed either in a witness statement or orally from the witness box.”
The judge was considering a factual dispute as to whether a couple had been divorced in Dubai and whether the wife knew of the Dubai proceedings.
THE JUDGMENT ON ASSESSING THE WITNESS EVIDENCE
When making my findings about the disputed facts I have relied first on those contemporary documents which I am satisfied are authentic. In Gestmin SGPS SA v Credit Suisse (UK) Ltd & Anor  EWHC 3560 (Comm)he said at paras 15 – 22:
“An obvious difficulty which affects allegations and oral evidence based on recollection of events which occurred several years ago is the unreliability of human memory.
While everyone knows that memory is fallible, I do not believe that the legal system has sufficiently absorbed the lessons of a century of psychological research into the nature of memory and the unreliability of eyewitness testimony. One of the most important lessons of such research is that in everyday life we are not aware of the extent to which our own and other people’s memories are unreliable and believe our memories to be more faithful than they are. 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.
Underlying both these errors is a faulty model of memory as a mental record which is fixed at the time of experience of an event and then fades (more or less slowly) over time. In fact, psychological research has demonstrated that memories are fluid and malleable, being constantly rewritten whenever they are retrieved. This is true even of so-called ‘flashbulb’ memories, that is memories of experiencing or learning of a particularly shocking or traumatic event. (The very description ‘flashbulb’ memory is in fact misleading, reflecting as it does the misconception that memory operates like a camera or other device that makes a fixed record of an experience.) 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 (referred to in the literature as a failure of source memory).
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 civil litigation itself subjects the memories of witnesses to powerful biases. The nature of litigation is such that witnesses often have a stake in a particular version of events. This is obvious where the witness is a party or has a tie of loyalty (such as an employment relationship) to a party to the proceedings. Other, more subtle influences include allegiances created by the process of preparing a witness statement and of coming to court to give evidence for one side in the dispute. A desire to assist, or at least not to prejudice, the party who has called the witness or that party’s lawyers, as well as a natural desire to give a good impression in a public forum, can be significant motivating forces.
Considerable interference with memory is also introduced in civil litigation by the procedure of preparing for trial. A witness is asked to make a statement, often (as in the present case) when a long time has already elapsed since the relevant events. The statement is usually drafted for the witness by a lawyer who is inevitably conscious of the significance for the issues in the case 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.
It is not uncommon (and the present case was no exception) for witnesses to be asked in cross-examination if they understand the difference between recollection and reconstruction or whether their evidence is a genuine recollection or a reconstruction of events. Such questions are misguided in at least two ways. First, they erroneously presuppose that there is a clear distinction between recollection and reconstruction, when all remembering of distant events involves reconstructive processes. Second, such questions disregard the fact that such processes are largely unconscious and that the strength, vividness and apparent authenticity of memories is not a reliable measure of their truth.”
In line with Leggatt J, I prefer to try to determine the truth by applying the dissenting speech of Lord Pearce in Onassis and Calogeropoulos v Vergottis  2 Lloyd’s Rep 403, HL:
“’Credibility’ involves wider problems than mere ‘demeanour’ which is mostly concerned with whether the witness appears to be telling the truth as he now believes it to be. Credibility covers the following problems. First, is the witness a truthful or untruthful person? Secondly, is he, though a truthful person, telling something less than the truth on this issue, or, though an untruthful person, telling the truth on this issue? Thirdly, though he is a truthful person telling the truth as he sees it, did he register the intentions of the conversation correctly and, if so, has his memory correctly retained them? Also, has his recollection been subsequently altered by unconscious bias or wishful thinking or by over-much discussion of it with others? Witnesses, especially those who are emotional, who think that they are morally in the right, tend very easily and unconsciously to conjure up a legal right that did not exist. It is a truism, often used in accident cases, that with every day that passes the memory becomes fainter and the imagination becomes more active. For that reason, a witness, however honest, rarely persuades a Judge that his present recollection is preferable to that which was taken down in writing immediately after the accident occurred. Therefore, contemporary documents are always of the utmost importance. And lastly, although the honest witness believes he heard or saw this or that, it is so improbable that it is on balance more likely that he was mistaken? On this point it is essential that the balance of probability is put correctly into the scales in weighing the credibility of a witness. And motive is one aspect of probability. All these problems compendiously are entailed when a Judge assesses the credibility of a witness; they are all part of one judicial process. And in the process contemporary documents and admitted or incontrovertible facts and probabilities must play their proper part.”
These views were echoed by Robert Goff LJ in The Ocean Frost  1 Lloyds Rep 1 at 57:
“Speaking from my own experience, I have found it essential in cases of fraud, when considering the credibility of witnesses, always to test their veracity by reference to the objective facts proved independently of their testimony, in particular by reference to the documents in the case, and also to pay particular regard to their motives and to the overall probabilities. It is frequently very difficult to tell whether a witness is telling the truth or not; and where there is a conflict of evidence such as there was in the present case, reference to the objective facts and documents, references to the witness’ motives and to the overall probabilities can be of very great assistance to a Judge in ascertaining the truth.”
These wise words are surely of general application and are not confined to fraud cases (although this case includes allegations of fraud). It is certainly often difficult to tell whether a witness is telling the truth and I agree with the view of Mr Justice Bingham that the demeanour of a witness is not a reliable pointer to his or her honesty.
In this case I have read the witness statements and listened to the oral explanations of the parties about events that happened up to seven years earlier. For me, that is a secondary source of evidence for determining what actually happened at that time. In my judgment, I should first rely on the contemporary documents. The mother plainly recognises that, as her response to some difficult contemporary documents was to say that the father had forged them. I have reached the conclusion that both parties have told me lies from the witness box, although the mother’s lies have been more extensive than those of the father. I have not reached this conclusion in reliance on the demeanour of the parents.”