Involuntary autobiographical memories in everyday life and in clinical disorders
Involuntary autobiographical memories are a basic mode of remembering that is at least as common in daily life as is voluntary goal-directed remembering. Both involuntary and voluntary memories are enhanced by emotion at the time of encoding and follow the same pattern of forgetting. Involuntary and voluntary remembering operate on the same episodic memory system and therefore are affected in similar ways by many aspects of emotional disorders. Thus, people with PTSD or depression have more negative involuntary memories – but they also have more negative voluntary memories.
In disorders involving reduced executive control (or reduced working memory capacity) and for memory measures that are sensitive to executive control (such as memory specificity) voluntary remembering will be hurt whereas the involuntary memory will be less influenced, because it takes place with less executive control. This differential effect is observed in recent work on involuntary memories in depressed individuals, as well as in normal aging.
Many of the characteristics of intrusive involuntary memories in clinical disorders can be explained in terms of the mechanisms that normally govern involuntary memories, when these mechanisms are applied to extreme situations (i.e., a traumatic event). For example, in everyday life involuntary remembering comes with more mood impact and physical reaction than does voluntary remembering, presumably due to reduced antecedent emotion regulation. This may lead to flashback experiences after highly stressful events as observed in PTSD.
Trauma and Autobiographical Memory
There is convincing evidence that posttraumatic disorders are characterised by impairments in autobiographical memory, including PTSD and complicated grief. There is also convincing biological evidence that trauma memories are fuelled by heightened arousal. To date, there is little attempt to merge the research of autobiographical memories, trauma memories, and emotional memories. This paper will review the studies of trauma-related autobiographical memories in the context of growing research on the biological and cognitive factors that influence how people remember aversive experiences. It will review recent studies from divergent paradigms that attempt to bring together different models to understand the complexity of autobiographical memory disturbances in traumatic stress disorders, with particular emphasis on the role of intrusive and distressing autobiographical memories.
Intrusive re-experiencing in posttraumatic stress disorder: Memory processes and their implications for therapy
Intrusive re-experiencing of aspects of the trauma is a core symptom of posttraumatic stress disorder. The reduction of these unwanted and distressing memories is one of the primary goals in treatment. The presentation will first give an overview of characteristics of re-experiencing and discuss to what extent these fit within the framework of autobiographical memories. The presentation will then turn to memory processes that are thought to explain the features of re-experiencing. Ehlers & Clark (2000) suggested that core features of reexperiencing can be explained by a combination of three memory processes (1) associative learning, (2) enhanced priming and (3) poor memory elaboration and integration with other relevant information. Several theories highlight the role of perceptual encoding. Evidence for each of these processes will be reviewed, and will be linked with other findings on autobiographical memory in PTSD, for example, overgeneral memory and perceptions of a fundamentally changed self. Treatment procedures used in Cognitive Therapy for PTSD (Ehlers et al., 2005) that build on the research findings will be described, in particular stimulus discrimination training, updating trauma memories and reclaiming your life assignments.
Memory specificity and affect regulation
There exist variations in the extent to which individuals report specific autobiographical memories when cued to do so. It is well-known that particularly depression and trauma-related disorders are associated with reduced memory specificity. But, also outside these clinical groups there are clear differences among individuals. Evidence suggests that these variations might be meaningfully related to differences in affect regulation. In some, an overgeneral memory style might represent a way of avoiding confrontation with emotionally painful memories. Memory truncation is then used as a passive avoidance strategy. We will present data from correlational and experimental studies that show that (a) reduced memory specificity is related to trauma histories, and particularly avoidance of trauma memories, (b) that reduced memory specificity is related to a more general tendency to avoid the negative things in life, (c) that the relationship between memory specificity and avoidance is particularly activated in a threatening context, (d) that reduced specificity is indeed related to lowered stress when confronted with negative experiences, and (e) that memory specificity can be brought under operant control. We will discuss these data against the background of a new functional-developmental model of memory specificity as a way to regulate affect.
Mental imagery: from flashbacks to flash-forwards
We experience mental imagery when we see in our mind’s eye, hear with our mind’s ear, and so on. Imagery has fascinating properties allowing us to remember or to make creative leaps. However intrusive, affect-laden images cause distress across a range of psychological disorders. In this talk I hope to illustrate how better understanding mental imagery is interesting in terms of theory, and also for therapy innovation.
(1) Mental imagery and emotion. It has long been assumed that mental imagery has a special relationship with emotion. However, while affect-laden images are striking to clinicians, experimental work has been lacking. We will discuss research in support of the hypothesis that compared to verbal processing, mental imagery has a more powerful impact on emotion ¹.
(2) Flashbacks. In comparison to studying memory that is deliberately recalled we know relatively little about involuntary, intrusive memories and images. Distressing intrusive images – “flashbacks” to a past trauma are the hallmark of post-traumatic stress disorder (PTSD). Visuospatial cognitive tasks – including the computer game Tetris - appear to protect against analogue flashback development ²
(3) Flash-forwards. Intrusive mental imagery can also occur of the future, such as “flashforwards” to suicidal acts ³ or manic pursuits in bipolar disorder ⁴. But can we harness the properties of deliberately simulating positive future events in imagery to improve emotional processing? People with depression can find it more difficult to deliberately generate positive imagery about the future. Experimental work using a cognitive bias modification framework to generate more positive imagery will be discussed ⁵.
Overall, research in experimental psychopathology can inform our understanding of the mechanisms underlying psychological disorders. It can suggest avenues for treatment innovation, though such innovations may look little like traditional therapies. In this context, mental imagery, rather than just verbal thoughts, warrants further exploration⁶.
References:
¹ Holmes, Mathews, Mackintosh & Dalgleish, 2008, Emotion; ² Holmes, Coode-Bates, James & Deeprose, 2009, PLoSONE ; ³ Holmes, Fennel, Crane & Williams, 2007, JBTEP; ⁴ Holmes, Geddes, Colom & Goodwin, 2008, BRAT; ⁵Holmes, Lang & Shah, 2009, J of Abnormal; ⁶ Holmes & Mathews, 2010, Clin PsyReview.
Intrusive Memories in Clinical Disorders
There is increasing evidence that intrusive memories of negative events are a transdiagnostic feature of a range of psychopathologies; most obviously, PTSD. Depressed individuals also experience intrusive memories, and there are similarities in the frequency, nature, and cognitive strategies employed to manage intrusive memories in depression and PTSD. In this talk I will discuss the role of intrusive memories across disorders, with an emphasis on depression. Specifically, I will describe experiments carried out by our group that have borrowed paradigms and methodologies from the PTSD literature to examine intrusive memories in non-clinical (i.e., high dysphoric) and clinical (currently and formerly depressed) samples. Our findings demonstrate the role of intrusive memories in depression and highlight the importance of memory characteristics, as well as the cognitive avoidance strategies that depressed individuals adopt in response to intrusions, in contributing to depression persistence. More recently we have begun to experimentally test the efficacy of targeting key variables linked to the maintenance of intrusive memories (e.g., problematic appraisals). Our overarching goals are to increase the effectiveness of cognitive treatments for depression by developing therapeutic strategies that directly target intrusive memories, and to arrive at a much needed empirically-supported theoretical account of intrusive memories in depressive disorders.
Difficulties Remembering the Past and Envisioning the Future in People with Complicated Grief and Trauma Histories
In my presentation, I will summarize our research group’s studies on autobiographical memory functioning in war veterans with and without posttraumatic stress disorder (PTSD), adults reporting childhood sexual abuse (CSA) histories, and bereaved adults with and without complicated grief. Key findings include overgeneral memory problems in war veterans with PTSD, especially in those trapped in their former identity as soldiers and marines, and an absence of this problem among adults reporting sexual abuse histories, except for those who believe they harbor repressed memories of abuse. Adults who have lost a spouse and suffer from complicated grief also exhibit difficulty retrieving specific autobiographical memories in response to cue words, but only for episodes not involving their dead spouse. Similarly, they experience difficulty envisioning counterfactual future scenarios that do not involve their dead spouse, but they do not experience difficulty envisioning future scenarios that would have involved their spouses if the latter were still alive. Difficulty imagining a future without one’s spouse, and the ease of imagining a (counterfactual) future with one’s (dead) spouse may provide the cognitive basis for the symptoms of hopelessness and yearning for the lost loved one.
Trauma and Autobiographical Memory: A View from Cognitive Psychology
I proceed by claiming that autobiographical memories for trauma and other trauma sequelae can be understood in terms of standard mechanisms of affect, cognition, and development applied to extreme events: events that are negative, emotionally intense, often unexpected and difficult to understand, and disruptive of normal development. For affect, I claim that availability increases with emotional intensity, especially for central aspects of the event, and that decreases in memory at high levels of intensity occur only in very specific instances such as those that cause an animal to freeze or go into shock. For cognition, I claim that highly intense, negative events that violate expectations have increased availability because they are better encoded and more often rehearsed. For development, I claim that the entire developmental trajectory is needed to predict reactions to events, making prior traumas often more important than the trauma being remembered and assessed for sequelae. These claims can be viewed as sophisticated null hypotheses. The goal is to see how far we can get before counter evidence requires modifications to them and our understanding of memory for and sequelae of trauma.
Overgeneral memories and their mechanisms: the relationship with rumination
There is now a growing body of evidence linking overgeneral autobiographical memory with ruminative thought. This keynote will review theoretical models (e.g., CaR-FA-X model, Williams et al., 2007; processing mode theory, Watkins & Teasdale, 2001; Watkins, 2008, Watkins, 2011), and the experimental evidence relevant to the relationship between rumination and overgeneral autobiographical memory. The talk will consider evidence that manipulating ruminative thinking influences the extent of overgeneral autobiographical memory (Watkins & Teasdale, 2001, 2004; Barnard et al., 2006; Raes et al., 2008) but also evidence that manipulating the tendency to make overgeneral or abstract representations including memories may influence rumination (e.g., Watkins et al., 2008, 2009). It is proposed that there is a reciprocal relationship between rumination and recall of overgeneral memories, reflecting a common process of abstract processing. Theoretical and clinical implications are considered including the value of targeting abstract thinking and increasing specific memories to reduce rumination.
Autobiographical Memory and Emotional Disorders: When planning strategies backfire
When attempting to retrieve personal memories, emotionally disturbed patients often differ from controls in that they retrieve summaries of events rather than an individual event. The talk will review recent evidence that helps address the origins, mechanisms and consequences of this memory deficit.
In research on origins and consequences, it has been shown that overgeneral memory is associated with a history of trauma under some circumstances; that it moderates the effect of mood on problem-solving in suicidal patients, moderates the effect of life-stress on the risk depression, and delays recovery from episodes of affective disorders, thus exposing patients to more affective disturbance over their lifetime.
At the level of mechanism, it appears to be associated with attentional Capture by self-relevant concerns and Rumination on these concerns, Functional Avoidance and reduced Executive function - the CaR-FA-X model (Psychol Bull, 2007). Common to all these processes is the use of Test-Operate-Test-Exit problem-solving strategies - that work well for external problems – in an attempt to alleviate low mood or memory intrusions, but which actually exacerbate rather than alleviate the mood.
This paper will review the implications of these data both for theories of autobiographical memory, and for clinical work with patients, where it has been found that mindfulness-based cognitive therapy decreases over-generality.