The English High Court’s Justice Leggatt (now a judge of the Court of Appeal) was called upon to decide a claim for £14 million in which the plaintiff relied on a contract said to have been entered into at the Horse & Groom public house in Great Portland Street in London. (Freshfields’ case note is here). In Blue v Ashley  EWHC 1928. His Honour reiterated earlier comments he had made to the effect that:
‘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.’
The modern approach, his Honour essentially said, is to get all the authentic documents and study them carefully and then allow memory only to fill in the gaps. This is what his Honour said:
‘IV. EVIDENCE BASED ON MEMORY
It is rare in modern commercial litigation to encounter a claim, particularly a claim for millions of pounds, based on an agreement which is not only said to have been made purely by word of mouth but of which there is no contemporaneous documentary record of any kind. In the twenty-first century the prevalence of emails, text messages and other forms of electronic communication is such that most agreements or discussions which are of legal significance, even if not embodied in writing, leave some form of electronic footprint. In the present case, however, such a footprint is entirely absent. The only sources of evidence of what was said in the conversation on which Mr Blue’s claim is based are the recollections reported by the people who were present in the Horse & Groom on 24 January 2013 and any inferences that can be drawn from what Mr Blue and Mr Ashley later said and did. The evidential difficulty is compounded by the fact that most of the later conversations relied on by Mr Blue were also not recorded or referred to in any contemporaneous document.
I have no reason to think that (with the possible exception of Mr Leach when he retreated from what he had said to Mr Blue’s solicitors) any of the witnesses were doing anything other than stating their honest belief based on their recollection of what was said in relevant conversations. But evidence based on recollection of what was said in undocumented conversations which occurred several years ago is problematic. In Gestmin SGPS SA v Credit Suisse (UK) Limited  EWHC 3560 (Comm), at paras 16-20, I made some observations about the unreliability of human memory which I take the liberty of repeating in view of their particular relevance in this case:
“16. 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.
17. 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).
18. 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.
19. 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.
20. 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 or 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.”
In the light of these considerations, I expressed the opinion in the Gestmin case (at para 22) that the best approach for a judge to adopt in the trial of a commercial case is to place little if any reliance 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.
A long list of cases was cited by counsel for Mr Blue showing that my observations in the Gestmin case about the unreliability of memory evidence have commended themselves to a number of other judges. In some of these cases they were also supported by the evidence of psychologists or psychiatrists who were expert witnesses: see e.g. AB v Catholic Child Welfare Society  EWHC 3334 (QB), paras 23-24, and related cases. My observations have also been specifically endorsed by two academic psychologists in a published paper: see Howe and Knott, “The fallibility of memory in judicial processes: Lessons from the past and their modern consequences” (2015) Memory, 23, 633 at 651-3. In the introduction to that paper the authors also summarised succinctly the scientific reasons why memory does not provide a veridical representation of events as experienced. They explained:
“… what gets encoded into memory is determined by what a person attends to, what they already have stored in memory, their expectations, needs and emotional state. This information is subsequently integrated (consolidated) with other information that has already been stored in a person’s long- term, autobiographical memory. What gets retrieved later from that memory is determined by that same multitude of factors that contributed to encoding as well as what drives the recollection of the event. Specifically, what gets retold about an experience depends on whom one is talking to and what the purpose is of remembering that particular event (e.g., telling a friend, relaying an experience to a therapist, telling the police about an event). Moreover, what gets remembered is reconstructed from the remnants of what was originally stored; that is, 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. Because the contents of our memories for experiences involve the active manipulation (during encoding), integration with pre existing information (during consolidation), and reconstruction (during retrieval) of that information, memory is, by definition, fallible at best and unreliable at worst.”
In addition to the points that I noted in the Gestmin case, two other findings of psychological research seem to me of assistance in the present case. First, numerous experiments have shown 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. Second, there is a powerful tendency for people to remember past events concerning themselves in a self-enhancing light. [fn: For example, when US college students were asked to remember their high school grades and their memories were checked against records of their actual results, they were highly accurate for A grades (89% correct) but extremely inaccurate for D grades (29% correct). See Daniel Schacter, “How the Mind Forgets and Remembers: The Seven Sins of Memory” (2001) pp150-1]
Mindful of the weaknesses of evidence based on recollection, I will make such findings as I can about what was said in the conversations on which Mr Blue relies and in particular in the crucial conversation on 24 January 2013 on which his claim is founded.’