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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.

RESEARCH addressing frequently asked questions

What is the Prevalence of Dissociative Amnesia for Traumatic Events?

  • Summary of Research Examining the Prevalence of Full or Partial  Dissociative Amnesia for Traumatic Events -- Studies show that a period of either partial or full amnesia is reported by between 30 and 90% of adult victims of childhood sexual abuse. Moreover, no study that has looked for evidence of traumatic or dissociative amnesia after child sexual abuse failed to find it.
  • The Evidence for Dissociative Amnesia - A Review of 100 years of Research
  • Freyd, J. J. (2003). Memory for abuse: What can we learn from a prosecution sample? Journal of Child Sexual Abuse, 12, 97-103.
  • This commentary responds to an article by Goodman et al. (2003) where 81% of adults with documented abuse during childhood reported the abuse on follow-up. This proportion that is somewhat higher than in some previously published prospective studies assessing memory for abuse. Freyd notes that many factors distinguish prospective prosecution samples (adults who were as children abused and then involved in child abuse prosecution cases) from adults who were as children abused and who were not subsequently involved in prosecution. Namely that these children were believed, protected, supported, and legitimated. Given that these should all contribute to memorability and thwart forgettability, Freyd notes that it is actually quite striking that 19% of the participants failed to disclose the abuse when interviewed later.

Responses:

Can Recovered Memories be Valid?

Is There Consensus Among Professionals on the Issue?

Is There a False Memory Syndrome?

  • Memory, Abuse, & Science: Questioning Claims about the False Memory Syndrome Epidemic by Pope, K. (1996). American Psychologist, 51, 957-974. This article examines the scientific validity of False Memory Syndrome as a diagnostic category. The author notes that psychology rests on science and that claims--no matter how popular, authoritative, or institutionalized--must be dispassionately examined in light  of the empirical evidence available to support them. If psychology is a scientific discipline, then claims by false memory proponents should be subject to the same scrutiny and held to the same scientific standards as those that are  routinely applied to other claims.
  • Science as Careful Questioning: Are Claims of a False Memory Syndrome  Epidemic Based on Empirical Evidence? Pope, K. (1997). American Psychologist, 52, 997-1006. In a follow up to his 1996 article (see above), the author reveals a lack of empirical evidence to support the claims of false memory proponents.
  • Crisis or Creation? A Systematic Examination of "False Memory Syndrome"
    by Dallam, S. J. (2001). Journal of Child Sexual Abuse, 9(3 & 4), 9-36. -- This article critically examines the assumptions underlying "False Memory Syndrome" to determine whether there is sufficient empirical evidence to support it as a valid diagnostic construct. Epidemiological evidence is also examined to determine whether there is data to support its advocates' claim of a public health crisis or epidemic.
  • The "False Memory" Defense: Using Disinformation and Junk Science in and out of Court by Whitfield, C. L. (2001). Journal of Child Sexual Abuse, 9(3 & 4). --Child sexual abuse is widespread and dissociative/traumatic amnesia for it is common. Accused, convicted and self-confessed child molesters and their advocates have crafted a strategy that tries to negate their abusive, criminal behavior, which we can call a "false memory" defense. Each of 22 of the more commonly used components of this defense is described and discussed with respect to what the science says about them.
  • What's in a name for memory errors? Implications and ethical issues arising from the use of the label "false memory" for errors in memory for details . by DePrince, A.P., Allard, C.B., Oh, H., & Freyd, J.J. (2004) Ethics & Behavior, 14, 201-233. ( FULL TEXT : http://dynamic.uoregon.edu/~jjf/traumapapers.html ) Since 1992 psychologists have increasingly used the term "false memory" when discussing memory errors for details, such as specific words within word lists. Use of the term to refer to errors in details is a shift in language away from other terms used historically (e.g., "memory intrusions"). We empirically examine this shift in language and discuss implications of the new use of the term "false memories." Use of the term presents serious ethical challenges to the data-interpretation process by encouraging over-generalization and misapplication of research findings on word memory to social issues.
  • Commentary: Response to Media Reports on Loftus' Bugs Bunny Study by Jennifer J. Freyd, University of Oregon (February 2003)

Why Does Trauma Leave Such Lasting Effects?

How Could a Child Forget Something as Horrible as Abuse?

  • Betrayal-Trauma Theory: -- Professor of cognitive psychology Jennifer Freyd created a useful web page explaining her theory of why children forget suppress awareness of some traumas and not others. 
  • Depue, B. E., Curran, T., & Banich, M. T. (2007). Prefrontal Regions Orchestrate Suppression of Emotional Memories via a Two-Phase Process. Science, 317 (5835), 215-219.

    Whether memories can be suppressed has been a controversial issue in psychology and cognitive neuroscience for decades. We found evidence that emotional memories are suppressed via two time-differentiated neural mechanisms: (1) an initial suppression by the right inferior frontal gyrus over regions supporting sensory components of the memory representation (visual cortex, thalamus), followed by (2) right medial frontal gyrus control over regions supporting multimodal and emotional components of the memory representation (hippocampus, amygdala), both of which are influenced by fronto-polar regions. These results indicate that memory suppression does occur and, at least in nonpsychiatric populations, is under the control of prefrontal regions.

  • See also, Putting a Lid on Bad Memories:The Mechanics of Memory Suppression

How Often do Children's Reports of Abuse Turn Out to be False?

More information on false memory claims:

 

Trauma and Dissociation in Children,The International Society for the Study of Trauma and Dissociation recently released a DVD-set  which is the recipient of 2008 APSAC Media Award. 
This 3-disk training set provides information about behavior impact of trauma on children, interviewing issues and prosecution.  It is accompanied by a 68 page Trainer's Guide.