Autobiographical memory of traumatic experiences: what are the…
Autobiographical memory of traumatic experiences: what are the possibilities and limitations of accurately recalling and depicting traumatic experiences?
Sotgiu, Rusconi: Why Autobiographical Memories for Traumatic and Emotional Events Might Differ: Theoretical Arguments and Empirical Evidence
5 arguments supporting the hypothesis that memories for traumatic and nontraumatic emotional events should be considered as qualitatively different recollections
5 arguments which can explain why autobiographical memories for traumatic and emotional events might be considered as two distinct classes of recollections
- First argument considers the objective features of traumatic and emotional events and their possible inﬂuence on the formation of memories for these events.
- The first argument considers the differences between the objective features of traumatic and emotional events, as well as their possible inﬂuence on the formation and maintenance of the memories for these events.
- Assumption: traumatic memories distinguish from emotional ones as trauma exposure is often associated with the development of psychological disorders involving memory disturbances.
- The second argument assumes that traumatic memories distinguish from emotional memories as trauma exposure is often associated with the development of psychological disorders involving memory disturbances.
- Traumatic experiences are more likely than emotional experiences to be forgotten and recovered.
- The third argument is that traumatic experiences are more likely than emotional experiences to be forgotten and then recovered.
- There's a possibility that emotional memories are socially shared more frequently than traumatic memories.
- The fourth argument concerns the possibility that emotional memories are shared with other people more frequently than traumatic memories.
- Trauma exposure may impair selected brain systems implicated in memory functions
- the ﬁfth argument is about neuroscience theory and research suggesting that trauma exposure may impair selected brain systems implicated in autobiographical memory functions.
1 - Objective Characteristics of Traumatic and Emotional Events Are Different
Differences - traumatic and emotional events (either + or -) might be expected to play a different role in the autobiographical memory because:
- Most influential definition of traumatic event (DSM-IV): traumatic events predict the onset of acute stress disorder (ASD), posttraumatic stress disorder (PTSD), as well as other psychiatric pathologies. Speciﬁcally, traumatic events are deﬁned as highly stressful occurrences in which the life and physical safety of a person are at risk or there is a risk of death or threat to the physical integrity of other people.
- Some authors have expressed concerns about the appropriateness of the trauma deﬁnition included in the DSMIV as it does not account for those life events (e.g., sudden divorce, discovering a partner’s affair, being ﬁred at work) that can be experienced and appraised as traumatic,even if they do not pose a serious threat to the life and physical safety of the person.
- Emotional events: personal or social occurrences that are relevant for the well-being of the individual and affect his or her goals, needs, and interests
- Hedonic valence (positive vs negative emotional events)
Findings support this BUT look only at traumatic vs POSITIVE emotional events (kanskje det negative huskes bedre uansett?)SUPPORT FOR TRAUMA SUPERIORITY THEORY
- they occur with a very different frequency
- It is arguable that infrequent traumatic experiences would leave a profound trace in the autobiographical memory as they constitute a turning point in the individual’s life story and form a central component of his or her personal identity
- On the other hand, frequently occurring emotional events are expected to be less consequential and less cognitively salient, being remembered with a lower degree of accuracy.
2 - Unlike Emotional Events, Traumatic Events Are Often Associated With Trauma-Related Psychological Disorders Affecting Memory Functioning
Traumatic events can have clinically significant long-term consequences - as opposed to + and - emotional events.
- Exposure to traumatic events is often associated with symptoms of acute and chronic stress, as well as with severe psychological disorders, including depression, anxiety, substance abuse, ASD, PTSD,anddissociation
- On the other hand, positive and negative emotional events, even if highly intense, usually result in short-lived experiences
SUPPORT FOR TRAUMA THEORYA number of researchers have postulated the existence of special psychological mechanisms responsible for these memory disorders.
- it has been documented that a relevant proportion of PTSD patients exhibit signiﬁcant memory disturbances, such as the inability to voluntarily recall important aspects of the trauma, the disorganization and fragmentation of trauma-related memories and overgeneral memory deﬁcits
Other clinical researchers proposed that, in order to account for the traumatic memory disturbances associated with PTSD, it is necessary to focus on the psychological mechanisms responsible for the incomplete emotional and cognitive processing of trauma.
- Dual representation theory of PTSD: traumatic memories associated with this disorder may be distinguished in two main categories depending on the conscious or unconscious processing of the trauma-related information (both at the time when the trauma originally happened and in subsequent time phases) and on its accessibility at the retrieval stage
- Verbally accessible memories: conscious representations of the trauma that can be deliberately retrieved from the autobiographical memory and generally do not interfere with PTSD patients’ mental health
- Situationally accessible memories: constitute unconscious representations ofthetraumathat cannot be voluntarily recalled, but are “accessed automatically when the person is in a context in which the physical features or meaning are similar to those of the traumatic situation” (p. 676). Distressing, repetitive, and unwanted ﬂashbacks are typical examples of this second category of traumatic memories. Importantly, Brewin et al. suggested that situationally accessible memories preserve the same code (e.g., perceptual, physiological, motor) of the information processed during theoriginaltraumaticevent.Thismayexplainwhytheexperience ofrelievingthe trauma is so frequent among PTSD patients.
- dissociative experiences and extreme arousal at the moment of the trauma may interfere with proper encoding and storage of trauma-related information, causing the development and maintenance ofthewell-knownreliving,avoidance,and arousal symptoms qualifying for PTSD.
- Importantly, according to van der Kolk and Fisler, traumatic memories associated with PTSD are not integrated into the person’s ordinary consciousness and lack a verbal narrative. Instead, they are organized on an implicit level and are retrieved as isolated fragments which take the form of automatic, somatosensory ﬂashbacks.
3 - Traumatic Experiences Are More Likely To Be Forgotten and Then Recovered
SUPPORTS (an extreme version of) TRAUMA THEORY
- "memory wars" about the reliability of recovered memories. Recovery memory debate
- childhood traumas
- repression (freud, hysteria, neurosis, difficult to demonstrate its existence empirically) vs dissociation (van der Kolk)
4 - Emotional Memories Are Shared More Frequently Than Traumatic Memories
Social sharing of emotion - the process where people exposed to emotional events are prone to talk about their experiences and feelings with other signiﬁcant persons
sharing one’s own experiences (both traumatic and emotional) with other people could affect the content of these experiences, namely how they are reconstructed in the autobiographical memory. For example, if the sharer and the sharing partner are close friends, the latter may help the former to reappraise his or her past negative experiences in waysthatarelessupsetting,thusfavoringanalternativememoryrepresentationof them which might also include signiﬁcant distortions and inaccuracies.
5 - Traumatic Events Are More Likely to Selectively Impair Brain Memory Systems
traumatic stress interferes with the ordinary functioning of the cerebral systems responsible for the encoding, storage, and retrieval of information concerning autobiographical eventsTHEORETICAL model of traumatic and emotional memory: 2 different brain memory systems operating in parallel:
It is concluded that traumatic memories resulting from these altered patterns of encoding are retrieved as isolated fragments without a coherent narrative and contextual information, and signiﬁcantly differ from emotional memories formed under ordinary circumstances THESE CONCLUSIONS ARE IN ACCORDANCE WITH THE TRAUMA THEORYEMPIRICAL SUPPORT FOR THE AFOREMENTIONED THEORETICAL MODEL:
- a "cool" cognitive system
- under acute stress, the cool system interrupts its normal activity as a consequence of the traumatic stress and operates in a dysfunctional manner
- a "hot" emotional system
- under acute stress, the hot system significantly increases its activity, thus becoming hyper-responsive to fear-provoking features of the event
- exposure to acute and chronic stress, as well as induced conditions of high levels of stress hormones (e.g., glucocorticoids), impairs the hippocampus health, thus altering its memory functions linked to the retrieval of spatiotemporal and declarative information
OTHER NEURAL CORRELATES:
- At the same time, there is also evidence that laboratory-induced stress and exposure to emotionally arousing stimuli enhance the amygdala activity, facilitating the encoding of emotional aspects of experience and increasing the probability that this information will be stored in and retrieved from the long-term memory
hippocampal atrophy resulting from trauma exposure should be considered as one of the possible determinants of the memory disturbances (e.g., fragmented memories, partial and full amnesia) frequently observed in PTSD patients
- PTSD patients show a signiﬁcant reduction in the volume of their hippocampus relative to control subjects. -> PS: neuroanatomical abnormalities in the hippocampus structure are often associated with factors other than trauma exposure, such as for example substance abuse, depression, and aging
Some conceptual issues related to the definitions of traumatic event currently employed by memory researchers
3 main theoretical perspectives on the nature and functions of traumatic memory
In the literature on traumatic memory, there is a longstanding controversy regarding the similarities and differences between memories for traumatic experiences and memories for other life experiences, generically labelled as nontraumatic experiences. This controversy has promoted the constitution of three main theoretical perspectives on the nature and functions of traumatic memory.
- Trauma theory
- Trauma Superiority theory
- Trauma Equivalency theory (aka ordinary memory argument)
- 1&2: maintain that traumatic memories have “special” properties, namely they are qualitatively different from other kinds of autobiographical memories.
- 1VS2: disagree in describing the psychological mechanisms underlying the formation of traumatic memories, as well as the phenomenological characteristics of these recollections (e.g., vividness, sensory components, memory quality).
- Trauma theory asserts that traumatic memories are more fragmented, disorganized, and less coherent compared to nontraumatic memories. Poorer memory for trauma has been linked to the activation of defense mechanisms such as, for example, dissociation and repression.
- Trauma Superiority theory holds that traumatic events are remembered better than nontraumatic events. Speciﬁcally, traumatic memories are assumed to be “superior” to other memories since they would be recalled more vividly and accurately than the latter.
- 3: "traumatic and nontraumatic memories do not signiﬁcantly differ with respect to their phenomenological characteristics". + the psychological and neurobiological mechanisms underlying the formation, maintenance and forgetting of both types of memories are equivalent, if not identical. In other words, no matter what sort of traumatic events people experience in their life, the recollection of all such stressful occurrences can be explained by ordinary memory processes.
Brewin: Episodic Memory, Perceptual Memory, and Their Interaction: Foundations for a Theory of Posttraumatic Stress Disorder
Section 1: Types of perceptual memory.
the different ways in which perceptual memory for nonautobiographical material has been studied, including brief and longer lasting representations.
Section 2: Long-term perceptual memory for autobiographical events
describes work on autobiographical memory, including the proposal that a type of perceptual memory is involved in the phenomenon of flashbulb memory.Perceptual details have invariably featured strongly in accounts of the recall of personal memories (Brewer, 1986, 1996), and this has been particularly true of events that are significant for the individual or include traumatic elements.
Flashbulb memories: recall for the circumstances in which individuals learned of shocking events such as the assassination of a prominent public figure. Flashbulb memories are thought to possess a primary, ‘live’ quality that is almost perceptual.
- people describing frightening experiences from the past often shift spontaneously into the present tense without realizing what they are doing (Pillemer, Desrochers, & Ebanks, 1998).
PS - flasbulb memory controversy over whether flashbulb memories involve a special mechanism such as Now Print! for preserving perceptual detail.
- Could it be that a surprising or emotion-arousing event triggered a “Now Print!” mechanism that indiscriminately recorded any ongoing neural activity in the form of an enduring image? Maybe not a perfect analogy
- General acceptance that:
- flashbulb memories of how a very significant event was learned about may endure over long periods (Berntsen & Thomsen, 2005).
- Flashbulb memories are sometimes more vivid and detailed than ordinary memories and better recalled than information about the event that triggered the flashbulb (Bohannon, 1988; Kvavilashvili, Mirani, Schlagman, Erskine, & Kornbrot, 2010; Kvavilashvili, Mirani, Schlagman, & Kornbrot, 2003; Rubin & Kozin, 1984; Talarico & Rubin, 2003, 2007; Weaver & Krug, 2004; Yarmey & Bull, 1978).
- Flashbulbs are associated with more intense emotional responses (Holland & Kensinger, 2010; Talarico, LaBar, & Rubin, 2004; Talarico & Rubin, 2007).
Once past the stage of sensory or iconic memory, perceptual memory involves synthesis and selection (see Types of Perceptual Memory). Likewise, amygdala activation prompted by arousing experiences leads to the subjective experience of a vivid memory and to the registration of more event details, but not to the registration of all event details (Holland & Kensinger, 2010; Kensinger, Garoff-Eaton, & Schacter, 2006).PSPS: just because a memory is strongly perceptual does not mean it is necessarily more accurate in every respect. One way to identify the presence of “special mechanisms” = to conduct taxometric analyses on flashbulb memory data to test whether scores fall onto a continuum (suggesting they are simply a vivid form of ordinary memory) or into two separate categories (suggesting they represent a different form of memory). -> FINDINGS SUPPORT THE FACT THAT FLASHBULB MEMORIES MAY HAVE A DIFFERENT UNDERLYING BASIS THAN OTHER ORDINARY MEMORIES
- Some findings show flashbulb memories are remarkably consistent (ex: 9/11, Margaret Thatcher), others have shown they flashbulb memories may show evidence of inconsistency and are not always more consistent than nonflashbulb memories (ex challenger explosion 3) (Larsen, 1992; Neisser & Harsch, 1992; Talarico & Rubin, 2003, 2007).
- Several authors have come to the following conclusion: flashbulb memories did not have special qualities but were likely ordinary memories that had been subject to additional rehearsal.
- Study for memories of the pope's death: (Lanciano & Curci, 2012) found clear evidence for a latent categorical structure. The authors concluded that their findings supported the idea of flashbulb memories as recollections of event-specific sensoryperceptual details, different from ordinary autobiographical memory.
- Other studies have found that the correlates of flashbulb and event memories for the same incident are different (Curci & Luminet, 2006; Hirst et al., 2009),
Section 3: Interaction between perceptual and episodic memory
reviews research on situations characterized by independence between perceptual memory and episodic memory.
Section 4: Perceptual and episodic memory in PTSD
Presentation of theories of PTSD is followed by reviews of the evidence that the disorder is accompanied simultaneously by a strengthening of involuntary perceptual memory and an impairment of voluntary episodic memoryPTSD - characterized by 2 very distinct effects relateing to memory for the traumatic event (both part of the diagnostic criteria in DSM-5):
PS: The theories all imply that a dissociation between perceptual and episodic memory for the trauma is at the heart of the condition. Dual representation theory of PTSD provides a detailed theoretical account of flashbacks. See page 75 (7)
- Frequent and intense involuntary memories consisting of trauma-related images that are experienced in the present ("flashbacks"). Flashbacks typically consist of a vivid, detailed multisensory image, usually visual but not necessarily so. Can vary from relatively mild to extreme (sjekk fil)
- (symptom B3: “dissociative reactions in which the individual feels or acts as if the traumatic event(s) were recurring”)
- Voluntary recall of the traumatic memory tends to be effortful, fragmented, and disorganized. This symptom refers to patients’ experience of gaps or discontinuities in their memory of the event and does NOT imply amnesia for the fact of the event having occurred.
- (symptom C3: “inability to remember an important aspect of the traumatic event(s)”).
Section 5: Trauma-related research on interactions involving perceptual and episodic memory
examines the evidence that in the presence of traumatic stimuli these systems may demonstrate functional independence.
Section 6: Reflections on the controversy concerning memory impairment in PTSD - VIKTIG VIKTIG VIKTIG
A variety of reasons for the continuing controversy over the nature of traumatic memory are put forward.4 possible explanations for the controversy despite the fact that there is very substantial evidence for both enhanced involuntary perceptual memory and impaired voluntary episodic memory in PTSD:
- the equating of processes in clinical and nonclinical samples
- the influence of the recovered memory controversy
- the equating of the semantic and episodic components of voluntary memory for the trauma
- the partial application of biological findings concerning emotion and memory
Section 7: Conclusions and recommendations
implications of this review for the study of memory, both in healthy participants and in those suffering from PTSD.
Memory in healthy participants
Important to consider the role of a separate perceptual memory system.
Involuntary conscious memory important in understanding the phenomenon of priming -> MIGHT AFFECT RECALL PERFORMANCE
- ex: reversed eyewitness suggestibility design
- misinformation effect when tested on their memory of a visual scene by means of a written checklist (recalled items that were in the narrative but not in the picture).
- No misinformation effect if the test is pictorial rather than verbal
The presence of these striking phenomenological accounts indicates that a complete account of recall and recognition, whether dealing with verbal or pictorial stimuli, needs to consider the interaction of episodic and perceptual memory. Our current understanding is that perceptual memory should not be expected to be necessarily veridical or consistent but rather show partial or selective accuracy. The occurrence of a perceptual intrusion nevertheless may contribute to memorial judgment, decision making, and controlprocessesinwaysweareonlybeginningtounderstand.For example, a recent neuroimaging study of the suppression of emotional memories found evidence for a two-stage process in which initial suppression of sensory components of the memory representation was followed by suppression of the multimodal and emotional aspects of the representation
- a wide variety of tasks are likely to lead to the spontaneous retrieval of autobiographical memories complete with visual scene details. Ex of such tasks:
- generating word associations
- passively viewing words and phrases
- deliberately recalling the past
- Conclusion: investigators should routinely assess the occurrence of involuntary perceptual memories with involuntary memory tasks such as recall of shocking events or of emotional scenes or pictures.
- For example, debates about the consistency or inconsistency of recall may be illuminated by looking separately at the consistency across time of voluntary and involuntary components. Whether involuntary memories are experienced in a particular context is likely to depend on the extent to which available cues are uniquely associated with them (Berntsen, Staugaard, & Sørensen, 2013)
- Investigation of the cued recall of valenced pictures.
- Funn: presenting cues was more likely to lead to involuntary perceptual memories when pictures were negative than when they were positive. Perceptual cues prompted these involuntary memories more often than verbal cues, and the occurrence of the involuntary memories was strongly related to recall performance (Brewin & Langley, 2012)
- Trauma film studies: involuntary memories of some of the picture stimuli continued sporadically over the succeeding week.
Memory in PTSD
Scientifically plausible that: under extreme stress there are differential effects on multiple memory systems.
Increased functioning of amygdala under stress: consistent with the formation of overly strong implicit memories related to autonomic conditioning and fear, including priming.However, the amygdala could also contribute to the encoding and consolidation of long-term perceptual memories that remain consciously accessible.
- Individual brain regions are affected by stress in very different ways:
- Study of neuronal morphology: the same stress experience produced dendritic atrophy and debranching in the hippocampus at the same time as producing enhanced dendritic arborization in the amygdala (Vyas, Mitra, Rao, & Chattarji, 2002)
- Latest version of dual representation theory (Brewin et al, 2010): during a traumatic event the encoding of S-reps (perceptual memories) is strengthened, whereas the encoding of C-reps (contextualized episodic memories), and the connections between S-reps and C-reps, is weakened. This leaves individuals able to retrieve C-reps of the event when they want to deliberately think or communicate about the trauma, although these are likely to be fragmented and disorganized. Reminders of the trauma are likely to lead to the automatic retrieval of S-reps, with vivid, decontextualized images being experienced as the event happening again in the present.
C-reps support episodic memories and verbal accounts of a traumatic event, whereas S-reps support involuntary flashbacks.
- S-reps: perceptual memories consist of sensation-near representations.
- S-reps capture the entire visual field, are egocentric (rely on the person’s own viewpoint), are automatically activated by related cues, and are relatively inflexible.
- S-reps are the product of processing in the dorsal visual stream, insula, and amygdala and are specialized for action on the environment.
- C-reps: contextualized representations.
- C-reps are selective, correspond to the focus of conscious attention, are allocentric (permit the adoption of alternative viewpoints), and can be strategically or automatically retrieved.
- C-reps are the product of processing in the ventral visual stream and medial temporal lobe
Ventral visual stream: involved in processing the context of visual objects and scenes.
Dorsal visual stream: specialized for action on the environment.
Testing the dual representation theory:
The kind of contextual-encoding deficit described by dual representation and other theories may lead to subsequent inappropriate generalization of past learning to novel situations in the form of either over- or undergeneralization
- Several findings have shown an association between PTSD and a specific deficit in allocentric spatial processing + that greater efficiency of temporal-lobe-based spatial configuration learning predicts fewer intrusive trauma memories of a trauma film
- Funn: individuals who had lesser contextual (allocentric) memory abilities were, as predicted, more vulnerable to developing involuntary memories of a traumatic film over the following week (Bisby et al., 2010). The naturally occurring intrusive memories of such individuals are also more strongly characterized by a lack of temporal context.
PS - contextualization: a process whereby selective attention leads to a recoding of the sensory input into an abstract structural description. This recoding then permits interaction with other knowledge, better organized consciously accessible memories, and reduced involuntary intrusions.The distinction between perceptual and episodic memory also provides an account of the apparently paradoxical effect, whereby repeatedly rehearsing a trauma memory in therapy leads to a reliable reduction in symptoms including the involuntary recall of that memory.
- The prediction that PTSD patients should therefore be equivalent to controls in learning initial stimulus–outcome associations but show a selective deficit in generalizing this learning to novel situations was recently confirmed (Levy-Gigi et al., 2012).
The distinction between perceptual and episodic representations may assist in explaining some instances of false memory creation.
- According to dual representation theory, by retrieving the distressing images and holding them in conscious attention, stronger C-reps are formed that provide a context for the memory in time and place. Further, associations between corresponding C-reps and S-reps are strengthened.
- Now, when reminders are encountered, the memories retrieved are contextualized and are experienced as belonging to the past rather than being a source of danger in the present. This account is compatible with many contemporary theories of human and animal cognition (Gold, 2004; Kesner & Rogers, 2004; Poldrack & Packard, 2003) that favor the idea that learning produces a variety of new representations that can collaborate or compete with existing memories for control of behavior
- Retrieval competition between alternative representations features strongly in the literature on verbal overshadowing (Brandimonte & Collina, 2008; Schooler & Engstler-Schooler, 1990), and has similarly been incorporated into several models of therapeutic change (Bjork & Bjork, 2006; Brewin, 2006).
These findings illustrate how perceptual and episodic memory systems under some conditions may collaborate to improve recall but under other conditions compete, potentially accounting for some cases of false trauma memories.
- Study (Brewin, Huntley, & Whalley, 2012): participants with PTSD wrote a trauma narrative + reported during what parts of the narrative they experienced flashbacks.They were later presented with stimuli from flashback and nonflashback parts of their narrative, mixed with foil stimuli, and judged whether they belonged to their own narrative. They also reported whether stimuli elicited a flashback during this recognition test.
- Overall, reporting a flashback at test was associated with significantly better recognition performance.
- However, flashbacks were occasionally reported to foil stimuli, which were then significantly more likely to be wrongly attributed to the person’s own narrative.
Autobiographical memory of traumatic experiences: what are the possibilities and limitations of accurately recalling and depicting traumatic experiences?
4. How memory for traumatic events might differ from other emotional memories
Traumatic events vs other emotional events (Sotgiu et al, i motsetning til artikkelen som mener at traumatiske minner fungerer under samme mekanismer som opererer ved andre minner)
Differences between traumatic events? Natural disasters, combat, etc (Boccia et al: different neural modifications underpin PTSD after different
traumatic events: an fMRI meta-analytic study)
Library of concepts to touch on
- Flashbulb memories
- Recovering from amnesia and regaining memory (+ repression, dissociation)
- Memory amplification
- Fragmentation, contextualization
- temporal context (perception of time)
3. Malleability of memories according to normal memory mechanisms
Sjekk artikkelen som mener at traumatiske minner fungerer under samme mekanismer som opererer ved andre minner
- STRESS & AROUSAL: Effects of cortisol on declarative memory (Wingenfeld & Tolf)
- Malleability due to external sources
- Malleability due to internal sources
2. Amygdala & Hippocampus double dissociation -> implications on autobiographical memory
+Focus on the role of the amygdala and the hippocampus on explicit memory (bl.a. gazz)
1. Central terms + normal memory processing
- Memory. Intensity & Valence. Encoding, retrieval, consolidation.
- Trauma + how it differs from other intensely negative emotional memories?
- Distinguishing between episodic and perceptual memory? Give an account of different types of memory and explain that we are interested in what is declarative/explicit and what remains implicit.
- A bit about the malleability of normal memory?