Repressed memory

Repressed memories are hypothesized memories having been unconsciously blocked, due to the memory being associated with a high level of stress or trauma. The theory postulates that even though the individual cannot recall the memory, it may still be affecting them consciously.^[1]

The existence of repressed memories is a controversial topic in psychology; some studies have concluded that it can occur in victims of trauma, while others dispute it. According to some psychologists, repressed memories can be recovered through therapy. Other psychologists argue that this is in fact rather a process through which false memories are created by blending actual memories and outside influences. Furthermore, some psychologists believe that repressed memories are a cultural symptom because there is no written proof of their existence before the nineteenth century.^[2]

According to the American Psychological Association, it is not possible to distinguish repressed memories from false ones without corroborating evidence.^[1] The term repressed memory is sometimes compared to the term dissociative amnesia, which is defined in the DSM-IV as “an inability to recall important personal information, usually of a traumatic or stressful nature, that is too extensive to be explained by ordinary forgetfulness”.

Amnesia is referred to any instance in which memories stored in the long-term memory are completely or partially forgotten, usually due to brain injury. According to proponents of the existence of repressed memories, such memories can be recovered years or decades after the event, most often spontaneously, triggered by a particular smell, taste, or other identifier related to the lost memory, or via suggestion during psychotherapy.^[3]

History

There is no documented writing about repressed memories or dissociative amnesia (as it is sometimes referred to), before the 1800s.^[4] The concept of repressed memory originated with Sigmund Freud in his 1896 essay Zur Ätiologie der Hysterie ("On the etiology of hysteria").^[5] One of the studies published in his essay involved a young woman by the name of Anna O. Among her many ailments, she suffered from stiff paralysis on the right side of her body. Freud stated her symptoms to be attached to psychological traumas. The painful memories had separated from her consciousness and brought harm to her body. Freud used hypnosis to treat Anna O. She is reported to have gained slight mobility on her right side.^[6] Freud's repressed memory theory joined his philosophy of psychoanalysis. Repressed memory has remained a heavily debated topic inside of Freud's psychoanalysis philosophy.

Research

Some research indicates that memories of child sexual abuse and other traumatic incidents may be forgotten.^[7] Evidence of the spontaneous recovery of traumatic memories has been shown,^[8][9][10] and recovered memories of traumatic childhood abuse have been corroborated.^[11]

Van der Kolk and Fisler's research shows that traumatic memories are retrieved, at least at first, in the form of mental imprints that are dissociated. These imprints are of the affective and sensory elements of the traumatic experience. Clients have reported the slow emergence of a personal narrative that can be considered explicit (conscious) memory. The level of emotional significance of a memory correlates directly with the memory's veracity. Studies of subjective reports of memory show that memories of highly significant events are unusually accurate and stable over time.^[12] The imprints of traumatic experiences appear to be qualitatively different from those of nontraumatic events. Traumatic memories may be coded differently from ordinary event memories, possibly because of alterations in attentional focusing or the fact that extreme emotional arousal interferes with the memory functions of the hippocampus.^[12]

Another possibility is that traumatic events are pushed out of consciousness until a later events elicits or triggers a psychological response. Support for this idea has come from studies in which trauma was temporarily induced. For example, a high percentage of female psychiatric in-patients ^{[13][14][15][16][17]} and outpatients ^[18][19][20] have reported experiencing histories of childhood sexual abuse. Other clinical studies have concluded that patients who experienced incestuous abuse reported higher suicide attempts and negative identity formation^[21] as well as more disturbances in interpersonal relationships.^[22]

There has also been significant questioning of the reality of repressed memories. There is considerable evidence that rather than being pushed out of consciousness, the difficulty with traumatic memories for most people are their intrusiveness and inability to forget.^[23] One case that is held up as definitive proof of the reality of repressed memories, recorded by David Corwin^[24] has been criticized by Elizabeth Loftus and Melvin Guyer for ignoring the context of the original complaint and falsely presenting the sexual abuse as unequivocal and true when in reality there was no definitive proof.^[25]

Retrospective studies (studying the extent to which participants can recall past events) depend critically on the ability of informants to recall accurate memories.^[26] The issue of reliability in participants’ introspective abilities has been questioned by modern psychologists. In other words, a participant accurately recalling and remembering their own past memories is highly criticized, because memories are undoubtedly influenced by external, environmental factors.

Psychologists Elizabeth Loftus and Katherine Ketcham are authors of the seminal work on the fallacy of repressed memory, The Myth of Repressed Memory (St. Martin's Press, 1994).

Cause

It is hypothesised that repression may be one method used by individuals to cope with traumatic memories, by pushing them out of awareness (perhaps as an adaptation via psychogenic amnesia) to allow a child to maintain attachment to a person on whom they are dependent for survival.^[27] Researchers have proposed that repression can operate on a social level as well.^[28] Psychogenic amnesia, now renamed dissociative amnesia, is found to increase in incidence after psychologically traumatic events such as war and natural disaster, which is consistent with the repression hypothesis.

Other theoretical causes of forgotten memories have stemmed from the idea of Retrieval-Influenced Forgetting,^[29] which states that “false” memories will be more accurately recalled when rehearsed more, than when actual memories get rehearsed. In this scenario, the action of rehearsing a falsified memory can actually take precedence over the actual memory that a person experiences. Anderson et al.^[29] discovered that rehearsal of novel information exhibits inhibitive processes on one’s ability to remember or recall the prior (real) memory. This conclusion is indicates that past memories can be easily forgotten, simply by attending to “real”, novel memories that are brought into awareness.

Authenticity

Memories can be accurate, but they are not always accurate. For example, eyewitness testimony even of relatively recent dramatic events is notoriously unreliable.^[30] Misremembering may result from confusion of memories of perceived and imagined events, as there may be overlap between features of the stored information comprising memories for perceived and imagined events. Memories of events are always a mix of factual traces of sensory information overlaid with emotions, mingled with interpretation and "filled in" with imaginings. Thus there is always skepticism about how valid a memory is as evidence of factual detail.

In one study where victims of documented child abuse were reinterviewed many years later as adults, 38% of the women denied any memory of the abuse.^[31]

Arguments against the existence of "traumatic amnesia" note that various manipulations can be used to implant false memories (sometimes called "pseudomemories"). These can be quite compelling for those who develop them, and can include details that make them seem credible to others.^[32] A classic experiment in memory research, conducted by Elizabeth Loftus, became widely known as "Lost in the Mall"; in this, subjects were given a booklet containing three accounts of real childhood events written by family members and a fourth account of a wholly fictitious event of being lost in a shopping mall. A quarter of the subjects reported remembering the fictitious event, and elaborated on it with extensive circumstantial detail.^[33] This experiment inspired many others, and in one of these, Porter et al. could convince about half of his subjects that they had survived a vicious animal attack in childhood.^[34]

Such experimental studies have been criticized^[35] in particular about whether the findings are really relevant to trauma memories and psychotherapeutic situations.^[36] Nevertheless, these studies prompted public and professional concern about recovered memory therapy for past sexual abuse. When memories are 'recovered' after long periods of amnesia, particularly when extraordinary means were used to secure the recovery of memory, it is now widely (but not universally) accepted that the memories are quite likely to be false, i.e. of incidents that had not occurred.^[37] It is thus recognised by professional organizations that a risk of implanting false memories is associated with some similar types of therapy. The American Psychiatric Association advises: "...most leaders in the field agree that although it is a rare occurrence, a memory of early childhood abuse that has been forgotten can be remembered later. However, these leaders also agree that it is possible to construct convincing pseudomemories for events that never occurred. The mechanism(s) by which both of these phenomena happen are not well understood and, at this point it is impossible, without other corroborative evidence, to distinguish a true memory from a false one."^[38][39]

Obviously, not all therapists agree that false memories are a major risk of psychotherapy and they argue that this idea overstates the data and is untested. ^[40][41][42] Several studies have reported high percentages of the corroboration of recovered memories,^[43][44] and some authors have claimed that the false memory movement has tended to conceal or omit evidence of (the) corroboration" of recovered memories.^[45]

Both true and false 'memories' can be recovered using memory work techniques, but there is no evidence that reliable discriminations can be made between them.^[46] Some believe that memories "recovered" under hypnosis are particularly likely to be false.^[47] According to The Council on Scientific Affairs for the American Medical Association, recollections obtained during hypnosis can involve confabulations and pseudomemories and appear to be less reliable than nonhypnotic recall.^[48] Brown et al. estimate that 3 to 5% of laboratory subjects are vulnerable to post-event misinformation suggestions. They state that 5 - 8% of the general population is the range of high-hypnotizability. Twenty-five percent of those in this range are vulnerable to suggestion of pseudomemories for peripheral details, which can rise to 80% with a combination of other social influence factors. They conclude that the rates of memory errors run 0 - 5% in adult studies, 3 - 5% in children's studies and that the rates of false allegations of child abuse allegations run 4 - 8% in the general population.^[41]

Neurological basis of memory

The neuroscientist Donald Hebb (1904–1985) was the first to distinguish between short-term memory and long-term memory. According to current theories in neuroscience, things that we "notice" are stored in short-term memory for up to a few minutes; this memory depends on 'reverberating' electrical activity in neuronal circuits, and is very easily destroyed by interruption or interference. Memories stored for longer than this are stored in long-term memory. Whether information is stored in long-term memory depends on its 'importance'; for any animal, memories of traumatic events are potentially important for the adaptive value that they have for future avoidance behaviour, and hormones that are released during stress have a role in determining what memories are preserved. In humans, traumatic stress is associated with acute secretion of epinephrine and norepinephrine (adrenaline and noradrenaline) from the adrenal medulla and cortisol from the adrenal cortex. Increases in these facilitate memory, but chronic stress associated with prolonged hypersecretion of cortisol may have the opposite effect. The limbic system is involved in memory storage and retrieval as well as giving emotional significance to sensory inputs. Within the limbic system, the hippocampus is important for explicit memory, and for memory consolidation; it is also sensitive to stress hormones, and has a role in recording the emotions of a stressful event. The amygdala may be particularly important in assigning emotional values to sensory inputs.^[49]

Although memory distortion occurs in everyday life, the brain mechanisms involved are not easy to study in the laboratory, but neuroimaging techniques have recently been applied to this subject. In particular, there have recently been studies of false recognition, where individuals incorrectly claim to have encountered a novel object or event, and the results suggest that the hippocampus and several cortical regions may contribute to such false recognition, while the prefrontal cortex may be involved in retrieval monitoring that can limit the rate of false recognition.^[50]

Amnesia

Amnesia is partial or complete loss of memory that goes beyond mere forgetting. Often it is temporary and involves only part of a person's experience. Amnesia is often caused by an injury to the brain, for instance after a blow to the head, and sometimes by psychological trauma. Anterograde amnesia is a failure to remember new experiences that occur after damage to the brain; retrograde amnesia is the loss of memories of events that occurred before a trauma or injury. For a memory to become permanent (consolidated), there must be a persistent change in the strength of connections between particular neurons in the brain. Anterograde amnesia can occur because this consolidation process is disrupted; retrograde amnesia can result either from damage to the site of memory storage or from a disruption in the mechanisms by which memories can be retrieved from their stores. Many specific types of amnesia are recognized, including:

• Childhood amnesia is the normal inability to recall memories from the first three years of life. Sigmund Freud was the first to observe this phenomenon and realized that not only do humans not remember anything from birth to three years, but they also have “spotty” recollection of anything occurring from three to seven years of age.^[51] There are various theories as to why this occurs: some believe that language development is important for efficient storage of long-term memories; others believe that early memories do not persist because the brain is still developing.
• A fugue state, formally dissociative fugue, is a rare condition precipitated by a stressful episode. It is characterized by episode(s) of traveling away from home and creating a new identity.^[52]

The form of amnesia that is linked with recovered memories is dissociative amnesia (formerly known as psychogenic amnesia). This results from a psychological cause, not by direct damage to the brain, and is a loss of memory of significant personal information, usually about traumatic or extremely stressful events. Usually this is seen as a gap or gaps in recall for aspects of someone's life history, but with severe acute trauma, such as during wartime, there can be a sudden acute onset of symptoms.^[53]

Effects of trauma on memory

'Betrayal Trauma Theory' proposes that in cases of childhood abuse, dissociative amnesia is an adaptive response, and that “victims may need to remain unaware of the trauma not to reduce suffering but rather to promote survival.”^[54] When stress interferes with memory, it is possible that some of the memory is kept by a system that records emotional experience, but there is no symbolic placement of it in time or space.^[55] Traumatic memories are retrieved, at least at first, in the form of dissociated mental imprints of the affective and sensory elements of the traumatic experience. Clients have reported the slow emergence of a personal narrative that can be considered explicit (conscious) memory.

Psychiatrist Bessel van der Kolk^[44] divided the effects of traumas on memory functions into four sets

• traumatic amnesia; this involves the loss of memories of traumatic experiences. The younger the subject and the longer the traumatic event is, the greater the chance of significant amnesia. He stated that subsequent retrieval of memories after traumatic amnesia is well documented in the literature, with documented examples following natural disasters and accidents, in combat soldiers, in victims of kidnapping, torture and concentration camp experiences, in victims of physical and sexual abuse, and in people who have committed murder.
• global memory impairment; this makes it difficult for subjects to construct an accurate account of their present and past history. "The combination of lack of autobiographical memory, continued dissociation and of meaning schemes that include victimization, helplessness and betrayal, is likely to make these individuals vulnerable to suggestion and to the construction of explanations for their trauma-related affects that may bear little relationship to the actual realities of their lives"
• dissociative processes; this refers to memories being stored as fragments and not as unitary wholes.
• traumatic memories’ sensorimotor organization. Not being able to integrate traumatic memories seems to be linked to posttraumatic stress disorder (PTSD).^[56]

According to van der Kolk, memories of highly significant events are usually accurate and stable over time; aspects of traumatic experiences appear to get stuck in the mind, unaltered by time passing or experiences that may follow. The imprints of traumatic experiences appear to be different from those of nontraumatic events, perhaps because of alterations in attentional focusing or the fact that extreme emotional arousal interferes with memory.^[44] van der Kolk and Fisler's hypothesis is that under extreme stress, the memory categorization system based in the hippocampus fails, with these memories kept as emotional and sensory states. When these traces are remembered and put into a personal narrative, they are subject to being condensed, contaminated and embellished upon.

When there is inadequate recovery time between stressful situations, alterations may occur to the stress response system, some of which may be irreversible, and cause pathological responses, which may include memory loss, learning deficits and other maladaptive symptoms. In animal studies, high levels of cortisol can cause hippocampal damage, which may cause short-term memory deficits; in humans, MRI studies have shown reduced hippocampal volumes in combat veterans with PTSD, adults with posttraumatic symptoms and survivors of repeated childhood sexual or physical abuse. Trauma may also interfere with implicit memory, where periods of avoidance may be interrupted by intrusive emotional occurrences with no story to guide them. A difficult issue is whether those presumably abused accurately recall their experiences.^[57]

Criticism

The existence of repressed memory recovery has not been accepted by mainstream psychology,^{[58][59][60][61]} nor unequivocally proven to exist, and some experts in the field of human memory feel that no credible scientific support exists for the notions of repressed/recovered memories.^[62][63] A survey revealed that whilst memory and cognition experts tend to be skeptical of repressed memory, clinicians are much more apt to believe that traumatic memory is often repressed.^[64] One research report states that a distinction should be made between spontaneously recovered memories and memories recovered during suggestions in therapy.^[65] A common criticism is that a recovered memory is tainted by, or a product of, the process of recovery or the suggestions used in that process.

The Working Group on Investigation of Memories of Child Abuse of the American Psychological Association presented findings mirroring those of the other professional organizations. The Working Group made five key conclusions:^[66]

1. Controversies regarding adult recollections should not be allowed to obscure the fact that child sexual abuse is a complex and pervasive problem in America that has historically gone unacknowledged;
2. Most people who were sexually abused as children remember all or part of what happened to them;
3. It is possible for memories of abuse that have been forgotten for a long time to be remembered;
4. It is also possible to construct convincing pseudo-memories for events that never occurred; and
5. There are gaps in our knowledge about the processes that lead to accurate and inaccurate recollections of childhood abuse.

^[66]

Many critics believe that memories may be distorted and false. Psychologist Elizabeth Loftus questions the concept of repressed memories and their possibility of them being accurate. Loftus focuses on techniques that therapists use in order to help the patients recover their memory. Such techniques include age regression, guided visualization, trance writing, dream work, body work, and hypnosis. Loftus' research indicates that repressed memory faces problems, such as memory alteration. In one case a teenage boy was able to “conjure a memory of an event that never occurred.” According to Loftus, if a stable person could be influenced to remember an event that never occurred, an emotionally stressed person would be even more susceptible.^[67]

Medico-legal issues

Serious issues arise when recovered but false memories result in public allegations; false complaints carry serious consequences for the accused. Many of those who make false claims sincerely believe the truth of what they report. A special type of false allegation, the false memory syndrome, arises typically within therapy, when people report the 'recovery' of childhood memories of previously unknown abuse. The influence of practitioners' beliefs and practices in the eliciting of false 'memories' and of false complaints has come under particular criticism.^[68] Sometimes these memories are used as evidence in criminal prosecutions.

It is generally accepted that people sometimes are unable to recall traumatic experiences. The current version (DSM-IV) of the Diagnostic and Statistical Manual of Mental Disorders, published by the American Psychiatric Association, states that "Dissociative amnesia is characterized by an inability to recall important personal information, usually of a traumatic or stressful nature, that is too extensive to be explained by ordinary forgetfulness."^[69] The term "recovered memory", however, is not listed in DSM-IV or used by any mainstream formal psychotherapy modality.^[70]

Legal state

Some criminal cases have been based on a witness's testimony of recovered repressed memories, often of alleged childhood sexual abuse. In some jurisdictions, the statute of limitations for child abuse cases has been extended to accommodate the phenomena of repressed memories as well as other factors. The repressed memory concept came into wider public awareness in the 1980s and 1990s followed by a reduction of public attention after a series of scandals, lawsuits, and license revocations.^[71]

A U.S. District Court accepted repressed memories as admissible evidence in a specific case.^[72] Dalenberg argues that the evidence shows that recovered memory cases should be allowed to be prosecuted in court.^[42]

The apparent willingness of courts to credit the recovered memories of complainants but not the absence of memories by defendants has been commented on: "It seems apparent that the courts need better guidelines around the issue of dissociative amnesia in both populations."^[73]

In 1995, the Ninth Circuit Court of Appeals ruled, in Franklin v. Duncan and Franklin v. Fox, Murray et al. (312 F3d. 423, see also 884 FSupp 1435, N.D. Calif.),^[74] that repressed memory is not admissible as evidence in a legal action because of its unreliability, inconsistency, unscientific nature, tendency to be therapeutically induced evidence, and subject to influence by hearsay and suggestibility. The court overturned the conviction of a man accused of murdering a nine-year-old girl purely based upon the evidence of a 21-year-old repressed memory by a lone witness, who also held a complex personal grudge against the defendant.^[75][76][77]

In a 1996 ruling, a U.S. District Court allowed repressed memories entered into evidence in court cases.^[78] Jennifer Freyd writes that Ross Cheit's case of suddenly remembered sexual abuse is one of the most well-documented cases available for the public to see. Cheit prevailed in two lawsuits, located five additional victims and tape-recorded a confession.^[10]

On 16 December 2005, the Irish Court of Criminal Appeal issued a certificate confirming a Miscarriage of Justice to a former nun, Nora Wall whose 1999 conviction for child rape was partly based on repressed-memory evidence. The judgement stated that:

"There was no scientific evidence of any sort adduced to explain the phenomenon of ‘flashbacks’ and/or ‘retrieved memory’, nor was the applicant in any position to meet such a case in the absence of prior notification thereof."

^[79]

Clinical relevance

Recovered memory therapy

Recovered memory therapy is a range of psychotherapy methods based on recalling memories of abuse that had previously been forgotten by the patient.^[80] The term "recovered memory therapy" is not listed in DSM-IV or used by mainstream formal psychotherapy modality.^[70][81] Opponents of the therapy advance the explanation that therapy can create false memories through suggestion techniques; this has not been corroborated, though some research has shown supportive evidence.^[82][83] Nevertheless, the evidence is questioned by some researchers.^[70][84][85] It is possible for patients who retract their claims—after deciding their recovered memories are false—to suffer post-traumatic stress disorder due to the trauma of illusory memories.^[86]

See also

• Dissociative identity disorder
• Gaslighting
• Interference theory
• Memory inhibition
• Pseudoscience
• Quackery

References

External links

• Memory controversies at DMOZ