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When Memory is the Evidence: Key Points from the Science of Human Memory

It is not unusual to encounter cases where the only evidence are accounts of what are claimed to be memories. This frequently occurs in cases of historic sexual abuse but can occur in many other types of case too, for example in a recent action outside the UK workers brought a case of forced unpaid overtime based solely on memories of hours worked up to 25 years ago. More generally, even when there is additional evidence the outcome of an action, criminal or civil, may nonetheless crucially depend on an account of a memory or set of memories. In these circumstances it would be useful for a court/tribunal to have an authoritative and accessible account of the nature of human memory - an account that they could draw upon to assist them in reaching more informed decisions. The recently published Memory & The Law Report, from the Research Board of the British Psychological Society aims to provide an accessible, widely agreed, set of guidelines about human memory that have been established through scientific research. The report lists 10 key guidelines and these are reproduced in Table 1 below.

Key Guidelines

i. Memories are records of people’s experiences of events and are not a record of the events themselves. In this respect, they are unlike other recording media such as videos or audio recordings, to which they should not be compared.

ii. Memory is not only of experienced events but it is also of the knowledge of a person’s life, i.e. schools, occupations, holidays, friends, homes, achievements, failures, etc. As a general rule memory is more likely to be accurate when it is of the knowledge of a person’s life than when it is of specific experienced events.

iii. Remembering is a constructive process. Memories are mental constructions that bring together different types of knowledge in an act of remembering. As a consequence, memory is prone to error and is easily influenced by the recall environment, including police interviews and cross-examination in court.

iv. Memories for experienced events are always incomplete. Memories are time-compressed fragmentary records of experience. Any account of a memory will feature forgotten details and gaps, and this must not be taken as any sort of indicator of accuracy. Accounts of memories that do not feature forgetting and gaps are highly unusual.

v. Memories typically contain only a few highly specific details. Detailed recollection of the specific time and date of experiences is normally poor, as is highly specific information such as the precise recall of spoken conversations. As a general rule, a high degree of very specific detail in a long-term memory is unusual.

vi. Recall of a single or several highly specific details does not guarantee that a memory is accurate or even that it actually occurred. In general, the only way to establish the truth of a memory is with independent corroborating evidence.
vii. The content of memories arises from an individual’s comprehension of an experience, both conscious and non-conscious. This content can be further modified and changed by subsequent recall.

viii. People can remember events that they have not in reality experienced. This does not necessarily entail deliberate deception. For example, an event that was imagined, was a blend of a number of different events, or that makes personal sense for some other reason, can come to be genuinely experienced as a memory, (these are often referred to as ‘confabulations’).

ix. Memories for traumatic experiences, childhood events, interview and identification practices, memory in younger children and older adults and other vulnerable groups all have special features. These are features that are unlikely to be commonly known by a non-expert, but about which an appropriate memory expert will be able to advise a court.

x. A memory expert is a person who is recognised by the memory research community to be a memory researcher. It is recommended that, in addition to current requirements, those acting as memory expert witnesses be required to submit their full curriculum vitae to the court as evidence of their expertise.

In summary, the picture of human memory currently emerging from scientific research is that memory is fragmentary and malleable and, most importantly, can contain errors and even wholly false memories of which the individual rememberer is completely unaware. Guidelines ‘i.’ through ‘v.’ provide more specific detail on this view of human memory and within the report itself further sections provide reviews of the relevant legal considerations and the scientific evidence that supports each guideline. A full reference section to the scientific literature is also included for those who wish to delve further. Consider then two major beliefs about human memory, prevalent in our courts, that the guidelines show to almost certainly be incorrect: the first is that fragmentary, incomplete, memories are unreliable and the second is that the recall of highly vivid details indicates that a memory is being recalled accurately. In fact, memory is always time-compressed and fragmentary (guideline ‘iv.’ See Table 1) it is a representation of experience and in no sense a literal record. An account of an experience that does not contain forgotten and poorly remembered details is the account which is unusual and which requires additional support if it is to be accepted as being of a memory.

The powerful belief that the more specific the details recalled the more likely a memory is be correct turns out to be pervasive, consider for example the following study:
In an experiment that featured a mock trial of a bank robbery, mock jurors were asked to judge the credibility of the evidence of the witnesses. One set of witnesses described events simply and without any details. For example, the (mock) witness might state “as the robber ran out of the bank I think he turned right and ran off down the street”. In another version the same witness (to a new mock jury) would state “as the robber, who I remember was wearing a green jumper, ran out of the bank I think he turned right and ran off down the street”. This second version of events was rated as far more likely to be correct than the first version. The effect is known as ‘trivial persuasion’ because by inclusion of a trivial or irrelevant but highly specific detail the perceived credibility of the evidence is markedly raised.

Other evidence reviewed in the Memory & The Law Report shows that there is no guarantee that any detail in a memory, whether specific or otherwise is correct. Recall of some very specific details, e.g. verbatim accounts of spoken utterances of more than a few words, etc., (see Table 1 and guidelines ‘v.’ and ‘vi.’ in the report for more of these types wholly implausible details) are very unlikely to be correct. Error and falsity seems especially characteristic of childhood memories but research has shown that this can be occur, and indeed does occur, for memories from any age. Consider the following memory, relayed to me appropriately enough by a barrister:



A middle-aged man recalled his father distracting him when he was a young boy (about 4 years old) by asking him who was the first man on the moon. He had been intensely interested in the moon landings when he was a young boy and this incident occurred while his father was on the telephone to his mother who had just given birth to his younger brother. My informant had a vivid and fond memory of his father placating him in this way, he was highly agitated by the birth, and in his memory he could ‘see’ his father on the telephone and almost ‘hear’ his voice. It was only decades later that he realized that his brother had been born in 1968, one year before the first moon landing.

Consider too another well know case that illustrates how memory can be simultaneously true and false. A woman was raped one evening in her apartment in New York. The police were called in and quickly developed a theory about who the attacker might be. The next day they held a line-up that include the suspect and several volunteers taken fairly randomly for the streets outside the police station. The victim singled out a man in the line-up and was powerfully confident this was the man, indeed she strongly recognized his face. But he was not the police suspect and, moreover, he had the perfect alibi: he had been on live television at the time the rape had taken in place. Subsequently it seems that in fact he had been on television in the woman’s apartment when the attack had taken place. The image of his face had been incorporated into her memory. Extensive research has now shown that inducing false details into memories and even creating wholly false memories is relatively easy and there is no doubt that this occurs spontaneously in everyday life. The research reviewed in Memory & The Law provides an accessible overview of the relevant studies and their findings (section 7 of the report provides a particular valuable review of research into identification parades).

Perhaps the main contribution of the report is to show how current scientific thinking about memory has come to fully appreciated that memories can be correct, they can be wrong (in their details), even wholly false, and, importantly, correct and wrong at the same time. With the latter combination of truth and error being more frequent than we have been able to acknowledge previously. Also of note is that these memory errors can arise non-consciously and without any intent on behalf of the rememberer. The evidence reviewed in the report does not cover malingering and lying it is, rather, solely concerned with what we might call honest errors or, in the case of false or confabulated memories what have been memorably termed honest lies.

In closing this article I would like to go beyond what is contained in the report and very briefly consider how wholly false memories might be created in, as an example, historic sexual abuse and also what motivations might be operating here. I choose adult memories of sexual abuse as an example because of a very strong belief that is held about reports of these sorts of memories which can best be summarized by the statement: Why would they say this it if it was not true? There are, of course, many reasons why someone might recount such memories when they are false, revenge and/or financial gain being potential candidate motivations. However, the motivation I want to consider here has a more psychological aim. Interestingly, this motivation was first suggested to me by a barrister who had acted in many of these cases and although it is pure speculation I have come to consider it a fine insight. Let us suppose that a person had a very difficult childhood with undermining, emotionally cold, and, perhaps, a physically aggressive parent or parental figure and that subsequent to childhood much else in their life had been bad. This individual remembers an incident from childhood that seems peculiar and seems to suggest some sort of abuse. They then try to image what else might have happened in this poorly remembered event, perhaps they create a visual mental image of what might have taken place. This leads to further imaging and they then begin to find it difficult to distinguish in their own mind what has been imagined versus remembered (technically this is known as a source error, one cannot recall the source of some information). Indeed, for them the images are now experienced as memories. This is the process known as imagination inflation and research shows that it is a powerful way in which to create false memories (see guideline ‘viii.’). Now the individual has a set of abuse memories and brings a case against the hated figure from childhood. The abuse memories may serve two purposes one being revenge on the person and the other, and this is the more interesting one, they serve to explain the various failures and disasters that have predominated in the victim’s life. Explaining one’s life in this way is a powerful motivation to develop a set of (false) memories that one experiences as true. As I commented above, this is purely speculation (although I think that in some cases it plays an important role), nonetheless the self-defining function that memories serve in a person’s life as a means of explaining who they are should not be overlooked, particularly in legal settings.

Finally, we should not lose sight of the fact that memory can be correct too. After all people are abused, attacked, and otherwise offended against and their memories will usually be a mix of well remembered details (normally just a few), a lot of forgotten details, and some details that incorrect but which they believe to be true or which they suspect might be true – that is what a typical memory looks like. Even though such memories are fragmentary and may contain (honest) errors they can nonetheless by true, true that certain experiences took place and true about at least some details. Indeed, at more general levels memory less prone to error (see guideline ‘ii.’). Thus, it is certainly possible that a person could remember they had been abused, attacked, or assaulted, etc. and be perfectly correct, while at the same having detailed memories that are wholly false. That is why additional evidence, independent of the rememberer, is virtually always required when judging the truth of memory (see guideline ‘vi.’).
Address for correspondence:
Martin A. Conway, Head,
Institute of Psychological Sciences
The Leeds Memory Group
University of Leeds
Leeds, LS2 9JT






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