Significant life events and the shape of memories to come: a hypothesis

Much has been said about how significant life events modulate our response to stimuli that are integral to those events. However, we know less about the more general consequences of these events, that is, how they affect subsequent learning abilities that are seemingly irrelevant to the initial event. Here, it is proposed that significant life events, most often stressful in nature, alter future learned responses by inducing nonspecific and persistent changes in neuroanatomical structures. These changes are induced in the presence of sex and stress hormones, which are released either in response to the event itself or as a consequence of stages of life. To illustrate, the effects of acute stressful experience on learning processes and their regulation by the release of hormones are reviewed. I discuss how these events and their hormonal consequences alter anatomical substrates such as those involved in neurogenesis and synaptogenesis. It is proposed that these modulatory processes allow past experiences to change the shape of memories to come. In this way, memorable life events become less about the past and more about the future.     

The frequency of voluntary and involuntary autobiographical memories across the life span

In the present study, ratings of the memory of an important event from the previous week on the frequency of voluntary and involuntary retrieval, belief in its accuracy, visual imagery, auditory imagery, setting, emotional intensity, valence, narrative coherence, and centrality to the life story were obtained from 988 adults whose ages ranged from 15 to over 90. Another 992 adults provided the same ratings for a memory from their confirmation day, when they were at about age 14. The frequencies of involuntary and voluntary retrieval were similar. Both frequencies were predicted by emotional intensity and centrality to the life story. The results from the present study—which is the first to measure the frequency of voluntary and involuntary retrieval for the same events— are counter to both cognitive and clinical theories, which consistently claim that involuntary memories are infrequent as compared with voluntary memories. Age and gender differences are noted.     

The nature of intrusive memories after trauma: the warning signal hypothesis

Individuals who had experienced a range of different traumas were asked to describe the quality and content of their intrusive memories. Visual intrusions were the most common, and thoughts were uncommon. Intrusion quality varied little with type of trauma. Intrusive memories commonly consisted of stimuli that were present immediately before the traumatic event happened or shortly before the moments that had the largest emotional impact (i.e., when the meaning of the event became more traumatic). It is suggested that intrusive memories are about stimuli that through temporal association with the trauma acquired the status of warning signals, i.e., stimuli that if encountered again would indicate impending danger. This explains why intrusive memories are accompanied by a sense of serious current threat. The warning signal hypothesis may be useful in guiding therapists in identifying the moments with the largest emotional impact that will need reprocessing in treatment, and in educating patients about the nature of reexperiencing symptoms.     

Current concerns in involuntary and voluntary autobiographical memories

Involuntary autobiographical memories are conscious memories of personal events that come to mind with no preceding attempts at retrieval. It is often assumed that such memories are closely related to current concerns – i.e., uncompleted personal goals. Here we examined involuntary versus voluntary (deliberately retrieved) autobiographical memories in relation to earlier registered current concerns measured by the Personal Concern Inventory (PCI; Cox & Klinger, 2000). We found no differences between involuntary and voluntary memories with regard to frequency or characteristics of current concern-related contents. However, memories related to current concerns were rated as more central to the person’s identity, life story and expectations for the future than non-concern-related memories, irrespective of mode of recall. Depression and PTSD symptoms correlated positively with the proportion of current concern-related involuntary and voluntary memories. The findings support the view that involuntary and voluntary remembering is subject to similar motivational constraints.     

The effect of emotional stress on involuntary and voluntary conscious memories

Clinical theories of post-traumatic stress disorder often claim that intrusive (involuntary) memories favour emotionally stressful material and that these memories come with more sensory imagery and emotional reliving compared to voluntary memories. However, these assumptions have not been verified experimentally. Here we obtained recordings of emotional reactions to aversive pictures at the time of encoding, as well as records of involuntary and voluntary memories of these pictures in a subsequent diary study. A comparison of individual ratings, obtained during encoding, of pictures recalled involuntarily and voluntarily showed that emotional stress at encoding increased overall accessibility, independent of whether recall was voluntary or involuntary. However at the time of recall, voluntary memories scored higher on narrative content and on measures of imagery. The findings are compatible with research on emotion and memory in general, but challenge clinical claims of differential involuntary versus voluntary access to emotionally stressful events.     

An investigation of traumatic life events and obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD), like most other psychiatric disorders, is suspected of being influenced by an interaction between life events and genes, both with regard to onset and course of illness. To date, no specific genes have been identified as playing a frequent role, and only a relatively few empirical studies have assessed the association between stressful life events (SLEs) and OCD. The present study builds on past research by examining the potential contributions from traumatic life events (TLEs) on the severity and symptom features in 265 individuals with Structured Clinical Interview for DSM-IV (SCID)-diagnosed OCD. Of these participants 54% endorsed having experienced at least one TLE in their life time. The presence of one or more TLEs was associated with increased OCD symptom severity. This relationship remained significant despite controlling for key variables including age, OCD age-of-onset, comorbidity, and depressive symptoms. In addition, obsessions/checking and symmetry/ordering were two of four symptom factors that were specifically associated with the occurrence of TLEs. These results are generally supportive of a pathoplastic relationship between TLEs and OCD symptomatology and thus suggest the need for greater systematic consideration of life stresses in research focused on the nature and treatment of OCD.     

Division of attention: The single-channel hypothesis revisited

Two experiments are reported in which subjects performed two forced-paced serial reaction time tasks separately and together at their maximum sustainable rates of information processing. Experiment 1 investigated the effects on the relationship between single- and dual-task performance of using tasks with the same or different input and output modality characteristics; an additional condition tested the effects on this relationship of using tasks with higher S-R compatibility. Experiment 2 investigated the effects on the relationship between single- and dual-task performance of varying information load (number of S-R alternatives). No significant differences were found in subjects' capacities to process information in single- and dual-task conditions. This finding was unaffected by: (a) the absolute information levels of the tasks, (b) whether inputs and/or outputs involved the same or different modalities, or (c) the level of S-R compatibility. The data from both experiments provide strong support for the single-channel hypothesis.     

Social skills and negative life events: Testing the deficit stress generation hypothesis

People who possess poor social skills have been hypothesized to experience negative events and consequently become vulnerable to psychosocial problems. This is characterized as the social skills deficit stress generation hypothesis. Two studies were conducted to examine this hypothesis. In study 1, 677 university students completed measures of social skills and negative life events that had occurred over the past three months. In study 2, 142 students participated in a 9 month, 3 wave longitudinal study that assessed social skills at times 1 and 3 and negative life events at times 2 and 3. Results of the investigations indicate generally negative associations between social skills and negative life events, but these associations were stronger concurrently than prospectively. Although social skills were predicted to be associated with negative life events that are social in nature, in most cases they were equally predictive of nonsocial negative life events. The associations between the social skills and life events were consistently small in magnitude. This research was supported in part by University of Kansas General Research allocation 3011-20-0038 and 3825-20-0038. The author expresses gratitude to Jeanne Flora, Clark Henry, and Michelle Menees for their assistance with coding.     

Social skills and negative life events: Testing the deficit stress generation hypothesis

People who possess poor social skills have been hypothesized to experience negative events and consequently become vulnerable to psychosocial problems. This is characterized as the social skills deficit stress generation hypothesis. Two studies were conducted to examine this hypothesis. In study 1, 677 university students completed measures of social skills and negative life events that had occurred over the past three months. In study 2, 142 students participated in a 9 month, 3 wave longitudinal study that assessed social skills at times 1 and 3 and negative life events at times 2 and 3. Results of the investigations indicate generally negative associations between social skills and negative life events, but these associations were stronger concurrently than prospectively. Although social skills were predicted to be associated with negative life events that are social in nature, in most cases they were equally predictive of nonsocial negative life events. The associations between the social skills and life events were consistently small in magnitude. This research was supported in part by University of Kansas General Research allocation 3011-20-0038 and 3825-20-0038. The author expresses gratitude to Jeanne Flora, Clark Henry, and Michelle Menees for their assistance with coding.     

The experience of emotions in everyday life

Abstract

A total of 47 employed adults were asked to record, in structured diaries, details of four episodes of emotion from the set that we regard as basic (happiness, sadness, anger, fear, disgust) and also to note occurrences of other emotions not in this set. Subjects experienced an average of about one episode of consciously recognised emotion a day, and in rating intensities they said that 11% of episodes were as intense as they could imagine. Anger was the most frequent of the basic emotions, and disgust the least frequent. There were no significant differences in rates or intensities of basic emotions as a function of gender. We predicted 69% of these emotions correctly from the goal-relevant events that elicited them: happiness was typically caused by achievements, sadness by losses, anger by frustration, and fear by threat, but the causation of disgust was more difficult to identify. In 31% of episodes pairs of basic emotions occurred in mixtures. Positive emotions tended to help plans, while negative ones tended to hinder them.     

Left-handedness and spatial reasoning abilities: The deficit hypothesis revisited

Left-handers with an inverted handwriting posture have been found by Levy and Reid to have relatively bilateral representation of tachistoscopically tested verbal and spatial functions. On the assumption that such bilateral representation is inefficient, it was hypothesized that left-inverted subjects (N = 20) would score lower than left- and right-handers with normal handwriting postures (Ns = 64, 66 respectively) on spatial reasoning. Results were consistent with the hypothesis. Possible alternative explanations and directions for future research are outlined.     

The coarse-to-fine hypothesis revisited: evidence from neuro-computational modeling

The human perceptual system seems to be driven by a coarse-to-fine integration of visual information. Different results have shown a faster integration of low-spatial frequency compared with high-spatial frequency (HSF) information, starting at early retinal processes. The difference in spatial scale decomposition remains throughout the lateral geniculate nucleus (Hubel & Wiesel, 1977) and V1 (Tootell, Silverman, & De Valois, 1981). During the last decade, a debate has emerged concerning the origin of the coarse-to-fine integration. Is it a constant, perceptually driven integration (Parker et al., 1992 and Parker et al., 1996)? Instead, the flexible use hypothesis suggests that different spatial frequency channels could be enhanced depending on the requirement of the task for high-level cognitive processes like categorization (Oliva and Schyns, 1997 and Schyns and Oliva, 1999). In two connectionist simulations, we have shown that global categorization performance could actually be better performed with HSF information when the amount of information is normalized across the different spatial frequency channels. Those results suggest that high-level requirement alone could not explain the coarse-to-fine bias toward LSF information. A hypothesis is proposed concerning the possible implication of the amount of data provided by different spatial frequency channel that might provide the perceptual bias toward LSF information.     

Action and emotion in everyday life

This study of naturally occurring behaviour employed a "beeper technique" to investigate the actions carried out by 152 subjects in eight different groups, viz. adult students, employed students who were also parents, unemployed, art students, doctoral students, alcoholics, retired people and a control group. Actions were sampled for seven subsequent days, five times per day between 8 a.m. and 10 p.m. at randomly selected occasions. Each action was rated on a number of variables, shortly after it was sampled (median delay approximately 10 min). Some of the findings were: Time allocation corresponded well with national estimates. Being under situational control was highly aversive. Instrumental and consummatory orientations correlated positively. The background variables were, on the whole, only rather weakly related to action ratings, but it was found that women and retired persons tended to report a higher level of well-being.     

Memory in posttraumatic stress disorder: properties of voluntary and involuntary, traumatic and nontraumatic autobiographical memories in people with and without posttraumatic stress disorder symptoms

One hundred fifteen undergraduates rated 15 word-cued memories and their 3 most negatively stressful, 3 most positive, and 7 most important events and completed tests of personality and depression. Eighty-nine also recorded involuntary memories online for 1 week. In the first 3-way comparisons needed to test existing theories, comparisons were made of memories of stressful events versus control events and involuntary versus voluntary memories in people high versus low in posttraumatic stress disorder (PTSD) symptom severity. For all participants, stressful memories had more emotional intensity, more frequent voluntary and involuntary retrieval, but not more fragmentation. For all memories, participants with greater PTSD symptom severity showed the same differences. Involuntary memories had more emotional intensity and less centrality to the life story than voluntary memories. Meeting the diagnostic criteria for traumatic events had no effect, but the emotional responses to events did. In 533 undergraduates, correlations among measures were replicated and the Negative Intensity factor of the Affect Intensity Measure correlated with PTSD symptom severity. No special trauma mechanisms were needed to account for the results, which are summarized by the autobiographical memory theory of PTSD.     

Recurrent images and early memories in social phobia

A recent model [Clark, D. M. & Wells, A. (1995). A cognitive model of social phobia. In R. Heimberg, M. Liebowitz, D. A. Hope & F. R. Schneier (Eds.), Social phobia: diagnosis, assessment and treatment (pp. 69-93). New York: Guildford Press] suggests that a distorted image of one's public self lies at the heart of social phobia. A previous study of spontaneous imagery [Hackmann, A., Surawy, C. & Clark, D. M. (1998) Seeing yourself through others' eyes: a study of spontaneously occurring images in social phobia. Behavioural and Cognitive Psychotherapy, 26, 3-12] confirmed that patients with social phobia frequently report experiencing negative, distorted, observer-perspective images when in anxiety provoking social situations. In the present study, 22 patients with social phobia were given a semistructured interview which aimed to further explore the nature of social phobic imagery. All participants were able to identify negative spontaneous images that were recurrent in the sense that their content appeared to be relatively stable over time and across different feared social situations. Most recurrent images involved several sensory modalities. Most recurrent images were linked to memories of adverse social events that clustered in time around the onset of the disorder. Taken together, the results suggest that in patients with social phobia, early unpleasant experiences may lead to the development of excessively negative images of their social selves that are repeatedly activated in subsequent social situations and fail to update in the light of subsequent, more favourable experiences. Implications of the findings for the understanding and treatment of social phobia are discussed.     

Vivid memories of emotional events: The accuracy of remembered minutiae

It has been claimed that emotional arousal causes a narrowing of attention, and, therefore, impoverished memory encoding. On this view, if details of an emotional event are reported subsequently, these details must be after-the-fact reconstructions that are open to error. Our study challenges these claims. Using a long-term (2-week), incidental learning procedure, we found that emotion promotes memory both for information central to an event and for peripheral detail. This contrasts with the results of explicit instructions to remember or to attend closely to the event, both of which seem to promote memory for the event's gist at the expense of detail. The likely mechanisms underlying these effects are discussed.