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.

• Aug 17, 2015: New study confirms neurological pathway for inaccessible traumatic memories. Special brain mechanism discovered to store stress-related, unconscious memories. Science News
  Some stressful experiences -- such as chronic childhood abuse -- are so traumatic, the memories hide like a shadow in the brain and can't be consciously accessed. Eventually, suppressed memories can cause debilitating psychological problems. Scientists have discovered how and where the brain stores those stressful memories and how to retrieve them. The findings could lead to new treatment for patients with repressed traumatic memories.
• FAQ on Traumatic Memory
  
  
• Recovered Memories: True or False? - Statement by the Leadership Council on recovered memories.

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:

• The Limitations of a Prospective Study of Memories for Child Sexual Abuse (Ross E. Cheit, 2003, Journal of Child Sexual Abuse, 12(2), 105 - 111.)
• Predicting Memory for Childhood Sexual Abuse: "Non-Significant" Findings with the Potential for Significant Harm (Eileen L. Zurbriggen & Kathryn Becker-Blease, 2003, Journal of Child Sexual Abuse, 12(2), 113 - 121.)
• Drawing Conclusions: Confusion Between Data and Theory in the Traumatic Memory Debate (Joyanna Silberg, 2003, Journal of Child Sexual Abuse, 12(2), 123 - 128.)
• The Overlapping Problems of Prosecution Sample Bias and Systematic Exclusion of Familial Child Sex Abuse Victims from the Criminal Justice System
  Wendy J. Murphy, 2003, Journal of Child Sexual Abuse, 12(2), 129 - 132.
• Cherish Your Exceptions (Frank W. Putnam, 2003, Journal of Child Sexual Abuse, 12(2), 133 - 135.)

Can Recovered Memories be Valid?

• Summary of Research Examining the Validity of Recovered Memories - Research has shown that the content of recovered memories are just as likely to be accurate as those of continuously held memories of trauma.
• Childhood Trauma Remembered: A Report on the Scientific Knowledge Base and Its Applications . (PDF Format 1.2 MB) A 24-page document published by the International Society for Traumatic Stress Studies.
• The Evidence for Dissociative Amnesia - A Review of 100 years of Research
• The Recovered Memory Archive - an Internet-based research project, directed by Professor Ross E. Cheit of the Taubman Center for Public Policy and American Institutions at Brown University. This Page lists more than 80 cases where recovered memories have been corroborated.
• Memory and Dimensions of Trauma: Terror May be 'All-Too-Well Remembered' and Betrayal Buried . By J. J. Freyd (2001). In J. R. Conte (Ed.) Critical Issues in Child Sexual Abuse: Historical, Legal, and Psychological Perspectives (pp.  139-173). Sage Publications: Thousand Oaks , CA
• False and Recovered Memories in the Laboratory and Clinic: A Review of Experimental and Clinical Evidence. (2004) -- Clinical Psychology, 11, 3-28. by David H. Gleaves, Steven M. Smith, Lisa D. Butler, & David Spiegel (FULL TEXT) -- This article reviews the clinical and laboratory evidence for recovered and  false memories. Available data suggest that, at least under certain circumstances, both false and recovered memories may occur. The authors suggest that the critical questions are: (a) how common is each type of memory phenomenon, (b) what factors lead to the occurrence of each (including under what conditions are each possible and/or likely to occur), and perhaps most importantly, (c) can these two types of memories be distinguished from each other? Describes laboratory analogues for both types of experiences and describes an empirical  research protocol that can demonstrate both phenomena and also compare the two. Such comparisons may help to determine the  causes of these phenomena, discover factors that influence the two, and hopefully reveal signature variables that could provide telltale signs differentiating false and recovered memories.
• What about Recovered Memories? (webpage by Jennifer Freyd, PhD)
• Freyd, J. J. (1996). Betrayal trauma: The logic of forgetting childhood abuse . Cambridge , MA : Harvard University Press.
• Sivers, H., Schooler, J. , Freyd, J. J. (2002). Recovered memories. In V.S. Ramachandran (Ed.) Encyclopedia of the Human Brain, Volume 4.(pp 169-184). San Diego , California and London: Academic Press. (FULL TEXT: PDF)
• Corwin, D. L., & Olafson, E. (1997). Videotaped Discovered of a Reportedly Unrecalled Memory of Child Sexual Abuse: Comparison with a Child Interview Videotaped 11 Years Before. Child Maltreatment, 2, 91-112. --This article presents the history, verbatim transcripts, and behavior observations of a child's disclosure of sexual abuse to Dr. David Corwin in 1984 and the spontaneous return of that reportedly unrecallable memory during a taped interview 11 years later. Because both interviews were videotaped, the case of Jane Doe is considered one of the most rigorously documented case studies of memory recovery.
• Traumatic Amnesia in Holocaust Survivors

Is There Consensus Among Professionals on the Issue?

• Position Statements by Professional Organizations - Most major professional associations that have examined this issue has recognized that full or partial forgetting of genuine memories of abuse can occur.
• Recovered Memories: True or False? - Statement by the Leadership Council on recovered memories.
• Childhood Trauma Remembered: A Report on the Scientific Knowledge Base and Its Applications . A 24-page document published by the International Society for Traumatic  Stress Studies . Download FULL TEXT Childhood Trauma Remembered (PDF Format 1.2 MB)
• Decision of United States District Court, District of Massachusetts -- "After considering [numerous] factors, this Court finds that the reliability of the phenomenon of repressed memory has been established, and therefore, will permit  the plaintiff to introduce evidence which relates to the plaintiff's recovered memories" (p.3).
• Responsible Science and 21st-Century Dilemmas. Annual Meeting of the American Association for the Advancement of Science, Seattle, 12-16 February 2004.
  Organizers: Jennifer J. Freyd, Ph.D., & Kathy Pezdek. Ph.D.
• Handout: Forgetting trauma stimuli in and out of the lab . (PDF) (DePrince, A.P., Becker-Blease, K.A., & Freyd, J.J.) Purchase Audio Cassette AS4130 Science of Child Abuse, Its Media Presentation and Forensic Considerations from Aven.co

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?

• The Effect of Childhood Trauma on Brain Development -- Summary of research examining the impact of childhood trauma on growth and development.

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?

• Review of Research Examining the Veracity of Children's Reports - research has repeatedly demonstrated that children rarely fabricate stories about being abused.
• Factors influencing children to self-disclose sexual abuse. (PDF)  Paine, M.L., & Hansen, D.J. (2002), Factors influencing children to self-disclose sexual abuse. Clinical Psychology Review, 22, 271-195. Copyright 2002, posted with permission from Elsevier)

More information on false memory claims:

• Legal and Ethical Issues Related to Allegations of Iatrogenic Creation of False Memories
  Articles examining how scientific research can inform the courts about the reliability of recovered memory evidence
• The Views of False Memory Proponents
  Writings by proponents of false memory syndrome
• U-Turn on Memory Lane - by Mike Stanton
  Mike Stanton heads the investigative team at The Providence Journal-Bulletin , where he shared a 1994 Pulitzer Prize for investigative reporting. He spent a year studying the recovered memory controversy and reports on what he learned.
• Holocaust Denial
  Holocaust deniers portray themselves as engaged in a legitimate, dispassionate quest for historical knowledge and "truth.".