Recovered Memories and Dissociative Amnesia - Scientific Evidence and Accuracy Rates
Recovered Memories
Recovered memories have been defined as the phenomenon of partially or fully losing parts of memories of traumatic events, and then later recovering part or all of the memories into conscious awareness. They have also been defined as the recollections of memories that are believed to have been unavailable for a certain period of time. There is very strong scientific evidence that recovered memories exist.This has been shown in many scientific studies. The content of recovered memories have fairly high corroboration rates.
Scientific evidence
There are many studies that have proven that the recovered memories of traumatic events exist. Brown, Scheflin and Hammond found 43 studies that showed recovered memories for traumatic events. The Recovered Memory Project has collected 101 corroborated cases of recovered memories. Hopper's research shows that amnesia for childhood sexual abuse is "beyond dispute." He states that "at least 10% of people sexually abused in childhood will have periods of complete amnesia for their abuse, followed by experiences of delayed recall" In one study of women with previously documented histories of sexual abuse, 38% of the women did not remember the abuse that had happened 17 years before. Most recovered memories either precede therapy or the use of memory recovery techniques. One studied showed that five out of 19 women with histories of familial sexual abuse either forgot specific details or had "blank periods" for these memories. Another study showed that "40% reported a period of forgetting some or all of the abuse". Herman and Harvey's study showed that 16% of abuse survivors had "complete amnesia followed by delayed recall". Corwin's individual case study provides evidence of the existence of recovered memories on videotape.Other researchers state:
Research has shown that traumatized individuals respond by using a variety of psychological mechanisms. One of the most common means of dealing with the pain is to try and push it out of awareness. Some label the phenomenon of the process whereby the mind avoids conscious acknowledgment of traumatic experiences as dissociative amnesia. Others use terms such as repression, dissociative state, traumatic amnesia, psychogenic shock, or motivated forgetting. Semantics aside, there is near-universal scientific acceptance of the fact that the mind is capable of avoiding conscious recall of traumatic experiences.
A body of empirical evidence indicates that it is common for abused children to reach adulthood without conscious awareness of the trauma.
There is scientific evidence in support of the phenomena of dissociation and recovered memory in Holocaust survivors.
Corroboration rates
Many studies show high corroboration rates for recovered memories of traumatic events. These rates vary from 50 - 75%, 64%, 77%, 50%, 75%, 68%,47%, and 70% . One study showed amnesia in 12 murderers, with "objective evidence of severe abuse...obtained in 11 cases". There are also additional studies showing the corroboration of recovered memories.
Brown, Scheflin, & Whitfield. (1999). Recovered Memories: The Current Weight of the Evidence in Science and in the Courts Journal of Psychiatry & Law, 27, 5-156. "Brown, Scheflin and Hammond reviewed 43 studies relevant to the subject of traumatic memory and found that every study that examined the question of dissociative amnesia in traumatized populations demonstrated that a substantial minority partially or completely forget the traumatic event experienced, and later recover memories of the event. By 1999, over 68 studies had been published that document dissociative amnesia after childhood sexual abuse. In fact, no study that has looked for evidence of traumatic or dissociative amnesia after child sexual abuse has failed to find it."
110 Corroborated Cases of Recovered Memory: http://blogs.brown.edu/recoveredmemory/case-archive/
Research discussing corroboration and accuracy of recovered memories https://pages.uoregon.edu/dynamic/jjf/suggestedrefs.html
Recall of childhood trauma: a prospective study of women's memories of child sexual abuse.
One hundred twenty-nine women with previously documented histories of sexual victimization in childhood were interviewed and asked detailed questions about their abuse histories to answer the question "Do people actually forget traumatic events such as child sexual abuse, and if so, how common is such forgetting?" A large proportion of the women (38%) did not recall the abuse that had been reported 17 years earlier. Women who were younger at the time of the abuse and those who were molested by someone they knew were more likely to have no recall of the abuse. The implications for research and practice are discussed. Long periods with no memory of abuse should not be regarded as evidence that the abuse did not occur.
Research on the Effect of Trauma on Memory
Research has shown that traumatized individuals respond by using a variety of psychological mechanisms. One of the most common means of dealing with the pain is to try and push it out of awareness. Some label the phenomenon of the process whereby the mind avoids conscious acknowledgment of traumatic experiences as dissociative amnesia . Others use terms such as repression , dissociative state , traumatic amnesia, psychogenic shock, or motivated forgetting . Semantics aside, there is near-universal scientific acceptance of the fact that the mind is capable of avoiding conscious recall of traumatic experiences. http://www.leadershipcouncil.org/1/tm/tm.htmlMemory disturbances and dissociative amnesia in Holocaust survivors
The following articles provide compelling scientific evidence in support of the phenomena of dissociation and recovered memory in Holocaust survivors. In addition to supporting the phenomenon in general, these articles also counter the argument that recovered memory is (a) no more than a recent cultural “fad” and (b) specific to false accusers of sexual abuse. http://blogs.brown.edu/recoveredmemory/scholarly-resources/holocaust/
Dissociation & the Fragmentary Nature of Traumatic Memories: Overview & Exploratory Study
"a systematic exploratory study of 46 subjects with PTSD which indicates that traumatic memories are retrieved, at least initially, in the form of dissociated mental imprints of sensory and affective elements of the traumatic experience: as visual, olfactory, affective, auditory and kinesthetic experiences. Over time, subjects reported the gradual emergence of a personal narrative that some believe can be properly referred to as “explicit memory”....Of the 35 subjects with childhood trauma, 15 (43%) had suffered significant, or total amnesia for their trauma at some time of their lives. Twenty seven of the 35 subjects with childhood trauma (77%) reported confirmation of their childhood trauma."http://www.trauma-pages.com/a/vanderk2.php
Kluft, RP (1995). The confirmation and disconfirmation of memories of abuse in Dissociative Identity Disorder patients: A naturalistic study. Dissociation 8: 253-8. "Nineteen, or 56%, had instances of the confirmation of recalled abuses. Ten of the 19, or 53%, had always recalled the abuses that were confirmed. However, 13 of the 19, or 68%, obtained documentation of events that were recovered in the course of therapy, usually with the use of hypnosis. Three patients, or 9%, had instances in which the inaccuracy of their recollection could be demonstrated."
Leadership Council Amicus Brief Appellant on Appeal from a Judgment of the Superior Court Brief of the Commonwealth of Massachusetts Supreme Judicial Court SJC No. 10382 AC No. 2007-p-0886 Commonwealth of Massachusetts, Appellee V. Paul Shanley, Leadership Council as Amicus Curiae
