Relationship between the number of life events and memory capacity in children

Stressful life events can result into declined memory performance at later age. One hypothesis suggests that stress affects the hippocampus, a brain area important for memory functioning. This study explored a potential relationship between the number of negative stressful life events and hippocampus-dependent declarative but not hippocampus-independent procedural memory performance in a community sample of 255 children, aged 6–12 years. The findings revealed that negative stressful life events were negatively related to verbal declarative memory, but not to nonverbal declarative and procedural memory. The memory impairments could not be accounted for by attention and sleep disturbances, and parenting characteristics as perceived by the child did not influence the vulnerability for the stress-related memory impairments. These findings provide further insight into the deleterious effects of negative stressful life events on learning in school-aged children.     

Null's the word: A comparison of memory quality for intensely negative and positive events

Research comparing memories of traumatic and positive events has produced inconsistent results. Complicating the issue, researchers employ a variety of measures (e.g., narrative or questionnaire) that make comparison across studies difficult. Further, this research has been criticised for lacking adequate statistical controls (Sotgiu & Mormont, 2008). Our study employed both narrative and questionnaire methodologies and compared memories for highly negative and positive events while controlling for retention interval, intensity of the event, and word count in the narrative measures. A total of 108 racially diverse college undergraduates wrote narratives and completed the Memory Characteristics Questionnaire about the most negative and the most positive event they had experienced, and memories were assessed for narrative coherence, language indicative of cognition, insight and sensory experience, subjective ratings of clarity, sensory detail, contextual detail, temporal detail, and the inclusion of thoughts and feelings. Results indicate no differences between memories for highly negative and positive events when retention interval and emotional intensity are controlled.     

The influence of a visuospatial grounding task on intrusive images of a traumatic film

Nonclinical participants watched a trauma film under two processing conditions. During part of the film participants carried out a concurrent visuospatial grounding task consisting of the construction of shapes out of plasticine (modelling clay), while the rest of the film constituted a control, no task condition. The visuospatial task was predicted to selectively compete for processing resources required for intrusive image formation. As predicted, spontaneous intrusive images during the succeeding week were significantly less common from those parts of the film that coincided with the concurrent task. The task had no effect on levels of distress or peritraumatic dissociation, consistent with the hypothesis that intrusions were reduced because the task competed for resources necessary for encoding into an image-based memory system.     

A randomised controlled trial to assess the effectiveness of providing self-help information to people with symptoms of acute stress disorder following a traumatic injury

BACKGROUND: Patients attending accident and emergency (A&E) may develop long-term psychological difficulties. Psycho-education has been suggested to reduce the risk of post-injury disorders. AIMS: We tested the efficacy of providing self-help information to a high-risk sample. METHODS: A&E attenders were screened for acute stress disorder and randomised to two groups: patients (n=116) receiving a self-help booklet and those who did not (n=111). A sample of 'low' scorers was also included (n=120); they did not receive a booklet. Psychological assessments were completed at baseline (within 1 month post-injury) and 3 and 6 months post-injury. RESULTS: Post-traumatic stress disorder (PTSD), anxiety and depression decreased (p<0.001) across time but there were no group differences in these measures or quality of life. However, subjective ratings of the usefulness of the self-help booklet were very high. CONCLUSIONS: This trial failed to support the efficacy of providing self-help information, as a preventative strategy to ameliorate PTSD.     

Enhanced perceptual priming for neutral stimuli occurring in a traumatic context: two experimental investigations

Intrusive memories in posttraumatic stress disorder are often triggered by stimuli that are perceptually similar to those present shortly before or during the trauma. The present study aims to examine the possible role of perceptual priming in this phenomenon. It further investigates whether the degree of perceptual priming is associated with dissociation and whether both perceptual priming and intrusive memories can be reduced through elaboration. Two experiments measured perceptual priming for neutral stimuli that immediately preceded a "traumatic" event. Volunteers (N=46, 92) watched a series of "traumatic" and neutral picture stories, and completed a blurred object identification (perceptual priming) memory task, and a recognition memory task. Participants in Experiment 1 were selected to score either high or low on the Trait Dissociation Questionnaire [Murray, Ehlers, & Mayou (2002). Dissociation and posttraumatic stress disorder: Two prospective studies of motor vehicle accident survivors. British Journal of Psychiatry, 180, 363-368]. They also completed a state dissociation measure in the session. Experiment 2 randomly allocated participants to an experimental condition designed to increase elaboration or to a control condition. This experiment also included a measure of intrusive memories. Both experiments found enhanced perceptual priming for the stimuli that immediately preceded the "traumatic" stories compared to those preceding neutral stories. Participants with high trait dissociation showed relatively stronger perceptual perceptual priming. The degree of perceptual priming for stimuli from the "traumatic" stories also correlated with state dissociation (Experiment 1). Experimental manipulation of the elaboration of the stories showed that elaboration reduced the enhanced perceptual priming effect and the relative probability of reexperiencing symptoms (Experiment 2). The results support the role of perceptual priming in intrusions after traumatic events.     

Effect of personal involvement in traumatic events on memory: The case of the Dolphinarium explosion

The association between memories of the terrorist explosion at the Dolphinarium discotheque in Tel Aviv and the level of personal involvement in the explosion was investigated. Memories of injured victims, uninjured eyewitnesses, and uninvolved controls who learned about the explosion from the mass media were compared. It was expected that memory of the explosion would be most and least detailed and accurate among the victims and the controls, respectively. The participants responded to an open-ended question about the explosion, as well as to specific and multiple-choice questions. Data analyses showed that the victims and the eyewitnesses remembered more details than the controls, and that the victims remembered both central and peripheral details more accurately than the other participants. Degree of involvement in the same traumatic experience was thus shown to be differentially associated with memory accuracy.     

A cross-modal weapon focus effect: The influence of a weapon's presence on memory for auditory information

To examine whether a weapon's presence impairs witnesses' memory for auditory information (as it impairs memory for visual information), we conducted two experiments in which undergraduates watched one version of a videotape depicting a male target who held either a weapon or a neutral object and conversed with a female character. The semantic content of his remarks was either easy or difficult to comprehend. The weapon's presence did not affect voice identification accuracy or memory for the target's vocal characteristics (e.g., pitch, loudness, speech rate) but did worsen memory for semantic content in the Difficult Comprehension condition. Our results can be explained by multiple resource models of attention, which propose separate resource “pools” for different sensory modalities.     

Metacognitive appraisal of memory inconsistency for traumatic events in Dutch veterans

Although memories of traumatic events are often remembered vividly, these memories are subject to change over time. In our previous study, we found that Dutch infantry veterans who had served in Iraq often reported stressful events at a second assessment point that they had not reported during a prior assessment point and vice versa. In the present exploratory study, we recontacted subjects from this previous study and asked how they explained the discrepancy in their memory reports between post-deployment assessment points 1 and 2. Common explanations were: interpreting the item differently, having forgotten the incident initially, repression and having accidentally incorporated someone else's experience into their own memory. Although such reports are not necessarily revelatory of the mechanisms driving discrepancies in memory reports over time, our study illuminates the metacognitive variables involved.     

Children's memories of experienced and nonexperienced events following repeated interviews

The present study compared 3- and 5-year-olds' reports of a true or false play interaction following repeated interviews. Final interviews were conducted either by the same researcher or by a new researcher. Age-related improvements in performance were evident. Also, 3-year-olds questioned repeatedly about an entirely false event made more errors in response to specific questions than 3-year-olds questioned repeatedly about false details of a true event. Five-year-olds who were questioned about the false event, however, were particularly accurate when answering questions about never-experienced body touch. Interviewer familiarity was associated with decreases in the amount of narrative detail 5-year-olds provided in free-recall and with increases in 3-year-olds' accuracy in response to direct questions. Both errors and response latency on a cognitive matching task were related to children's suggestibility.     

The effect of cognitive load and hyperarousal on negative intrusive memories

Clinical theories of post-traumatic stress suggest that encoding processes at the time of a trauma are critical in determining whether intrusive memories will develop. Potential mechanisms that might influence the development of intrusive memories were studied, as was objective memory performance. In an analogue design, 65 participants were randomised to three conditions (cognitive load, hyperventilation, and control), and then watched a film of traumatic content. Intrusive memories were recorded during the experimental phase and at 1-week follow-up. Support was found for the prediction that verbal cognitive load and hyperventilation would facilitate intrusion development immediately following exposure to the trauma film; however, this was not maintained at follow-up. Consistent with cognitive models of post-traumatic stress, thought suppression and the distress associated with intrusive experiences mediated the relationship between distress caused by the film and intrusions at 1-week follow-up. Objective memory testing indicated that the three experimental groups showed similar recall and recognition performance for the content of the film; however, relative to the control group, individuals in the cognitive load condition were significantly less able to place film scenes in the correct order.     

Predictors of posttraumatic stress in children following injury: The influence of appraisals, heart rate, and morphine use

Prospective studies of posttraumatic stress disorder (PTSD) in children that investigate simultaneously both cognitive and biological or psychophysiological predictors are rare. The present research reports on the impact of cognitive factors (trauma-related appraisals) and biological indicators (heart rate, morphine use) in predicting PTSD and depression symptoms following single-incident trauma. Children and adolescents (N = 48) were assessed within 4 weeks of an injury that led to hospital treatment and followed up 6-months later. While morphine did not predict initial PTSD severity, it was associated with lower levels of PTSD at follow-up. Reductions in PTSD symptoms (change scores) between assessments were similarly associated with morphine dosage. Trauma-related appraisals also contributed to PTSD and depression symptom severity. While slightly different patterns of results were obtained depending on whether static or change scores were examined, as a whole the study adds to a growing literature that morphine has the potential to reduce PTSD symptoms severity. Likewise the relationship between unhelpful trauma appraisals and posttrauma psychopathology was replicated.     

Short-term memory for time in children and adults: A behavioral study and a model

This experiment investigated the effect of the short-term retention of duration on temporal discrimination in 5- and 8-year-olds, as well as in adults, by using an episodic temporal generalization task. In each age group, the participants' task was to compare two successive durations (a standard and a comparison duration) separated by a retention interval of 500ms, 5s, or 10s, with the order of presentation of these two durations being counterbalanced. The results revealed a shortening effect for the first presented stimulus in all of the age groups, although this was greater in the younger children, thereby indicating the presence of a negative time-order error. Furthermore, introducing a retention delay between the two durations did not produce a shortening effect but instead flattened the generalization gradient, especially in the younger children. However, this flattening of the generalization gradient with the retention delay was more marked between 500ms and 5s than between 5s and 10s. Thus, retaining the first duration in short-term memory during a task requiring the comparison of two successive durations reduced temporal discrimination accuracy and did so to a greater extent in the younger children.     

The traumatic memory debate: A failure in scientific communication and cooperation

Perhaps no other topic in recent history has generated such emotionality as the ongoing traumatic memory debate involving alleged reports of physical and sexual abuse. The literature on this topic is replete with reliance on anecdotal statements, unwarranted and grossly overstated generalizations, emotionally laden conclusions, attacks and counterattacks. This state of affairs has resulted in creating a polarization between cognitive memory researchers and clinical researchers who are attempting to resolve the debate through scientific inquiry. Unfortunately, the databases on both sides of the issue are weak. The purpose of this article is to highlight the key issues at the center of this debate in an attempt to move the debate forward. It is argued that resolution of this debate can only be achieved by conducting appropriately designed clinical research with a population of traumatically abused subjects. To achieve this objective, both sides need to suppress their emotional rhetoric, open lines of communication, and engage in cooperative research efforts. This issue is too important for both the field of psychology and society as a whole to remain polarized and unresolved.     

Internalising symptoms and verbal working memory in school‐age children: A processing efficiency analysis

The current study investigated differential contributions of internalising symptoms (state anxiety, trait anxiety, depression) to school‐age children's verbal short‐term (STM) and working memory (WM) span accuracy and efficiency (microanalysis of response times). Children's (N = 125, M_age = 11.44 years) STM/WM was assessed with simple/complex span tasks. Our analyses revealed that: (a) children with high levels of state anxiety displayed reduced simple span accuracy (on Word span) and poorer efficiency on both simple (preparatory intervals, interword pauses) and complex span (preparatory intervals) response time segments; (b) trait anxiety was a negative predictor of children's complex span accuracy, as well as their efficiency on both simple (word durations) and complex span (interword pauses) response time measures; (3) depressive symptoms predicted longer simple span interword pauses. Findings indicate that while all internalising symptoms were predictive of children's poorer memory search efficiency, especially during the “silent”, executive intervals (interword pauses), anxiety symptoms were specifically predictive of children's impaired span accuracy and other efficiency indicators (preparatory intervals, word durations). The study highlights the differential contributions of state, trait anxiety, and depressive symptoms to STM/WM in children, emphasising the need to measure both accuracy and efficiency to assess the role that such symptoms play in children's performance.     

The traumatic memory debate: A failure in scientific communication and cooperation

Perhaps no other topic in recent history has generated such emotionality as the ongoing traumatic memory debate involving alleged reports of physical and sexual abuse. The literature on this topic is replete with reliance on anecdotal statements, unwarranted and grossly overstated generalizations, emotionally laden conclusions, attacks and counterattacks. This state of affairs has resulted in creating a polarization between cognitive memory researchers and clinical researchers who are attempting to resolve the debate through scientific inquiry. Unfortunately, the databases on both sides of the issue are weak. The purpose of this article is to highlight the key issues at the center of this debate in an attempt to move the debate forward. It is argued that resolution of this debate can only be achieved by conducting appropriately designed clinical research with a population of traumatically abused subjects. To achieve this objective, both sides need to suppress their emotional rhetoric, open lines of communication, and engage in cooperative research efforts. This issue is too important for both the field of psychology and society as a whole to remain polarized and unresolved.     

Improving time discrimination in children and adults in a temporal bisection task: The effects of feedback and no forced choice on decision and memory processes

In children aged 5 and 8 years old as well as in adults, Experiment 1 tested the effect of feedback on temporal performance using a bisection task. Experiment 2 added a no-forced-choice condition by giving the participants the possibility of responding “I don't know”. The results of Experiment 1 showed that providing feedback increased the bisection point value (point of subjective equality) in all age groups and increased sensitivity to time in the youngest children. The results of Experiment 2 showed that the proportion of “I don't know” responses peaked at the probe duration close to the arithmetic mean of the two anchor durations and decreased as the distance from this central value increased in both the adults and the 8-year-olds. In the 5-year-olds, the proportion of “I don't know” responses was lower and remained constant whatever the probe duration values. Unlike in the youngest children, giving the adults and the 8-year-olds the opportunity to respond “I don't know” increased their sensitivity to time. The modelling of our data suggests that providing feedback in a temporal bisection task affects both the memory and the decision processes. However, whereas the feedback-related effect had a similar effect on decision processes across the age groups, it had an opposite effect on memory processes in the 5-year-olds and the older participants, decreasing the variability of the memory representation of the anchor durations in the former while increasing it in the latter. Finally, in bisection, feedback only improved temporal performance when the memory for duration was imprecise as in the case of the children.     

The effect of arousal on memory for emotionally-relevant information: a study of skydivers

The aim of the present study was to test memory for information under conditions of extreme arousal in an analogue design to mimic hyperarousal during trauma exposure. Prior to their skydive, 70 novice skydivers were administered measures of fear, heart rate, and anxiety sensitivity. Half the participants learnt a list of words that varied in both relevance to their skydive and valence (irrelevant/relevant, negative/neutral) on the plane (skydivers), and remaining participants learnt an identical list of words on the ground (delayed controls). Following the skydive, participants completed free recall and recognition tasks; heart rate, dissociation, and subjective arousal were also measured. Consistent with an attentional narrowing hypothesis, skydivers recalled comparable a comparable number of relevant words as delayed controls, but significantly less irrelevant words. In terms of recognition performance, skydivers displayed better recognition of relevant words but poorer recognition of irrelevant words than delayed controls. Valence of words did not alter the pattern of results. The implications of the findings are discussed in the context of understanding memory processes under conditions of high threat.     

Hierarchical forms processing in adults and children

Two experiments examined child and adult processing of hierarchical stimuli composed of geometric forms. Adults (ages 18-23 years) and children (ages 7-10 years) performed a forced-choice task gauging similarity between visual stimuli consisting of large geometric objects (global level) composed of small geometric objects (local level). The stimuli spatial arrangement was manipulated to assess child and adult reaction times and predisposition toward local or global form categorization under two distinct trial conditions, with varied density of the local forms comprising the global forms. In Experiment 1, children and adults were presented with common, simple geometric shape hierarchical forms composed of ovals and rectangles. In Experiment 2, adults were presented with hierarchical forms composed of the simple geometric shapes, ovals and rectangles, and additional novel complex geometric shapes, “posts” and “arches.” Results show a clear increase of global processing bias across the age ranges of the individuals in the study, with children at 10 years performing similarly to adults on the simple stimuli. In addition, adults presented with the novel complex geometric shapes showed a significant reduction in global processing bias, indicating that form novelty and complexity lead to additional attention to local features in categorization tasks.     

Influence of memory theme and posttraumatic stress disorder on memory specificity in British and Iranian trauma survivors

This study investigated the influence of culture, memory theme and posttraumatic stress disorder (PTSD) on autobiographical memory specificity in Iranian and British trauma survivors. Participants completed the Autobiographical Memory Test and PTSD Diagnostic Scale. The results indicated that the British group provided significantly more personal-themed memories than the Iranian group, while the Iranian group provided significantly more social-themed memories than the British group. The British group also provided a significantly greater proportion of specific personal-themed and social-themed memories than the Iranian group. Overall, in both cultural groups memory specificity was found to be significantly correlated with PTSD symptoms. These findings provide further evidence that regardless of memory theme, specificity of autobiographical memories function to differentiate the self from others and reaffirm the independent self. They also further highlight that pan-culturally an overgeneral retrieval style may be employed by those with PTSD symptoms.     

The influence of working memory on reading growth in subgroups of children with reading disabilities

This 3-year longitudinal study determined whether (a) subgroups of children with reading disabilities (RD) (children with RD only, children with both reading and arithmetic deficits, and low verbal IQ readers) and skilled readers varied in working memory (WM) and short-term memory (STM) growth and (b) whether growth in an executive system and/or a phonological storage system mediated growth in reading performance. A battery of memory and reading measures was administered to 84 children (11-17 years of age) across three testing waves spaced 1 year apart. The results showed that skilled readers yielded higher WM growth estimates than did the RD groups. No significant differentiation among subgroups of children with RD on growth measures emerged. Hierarchical linear modeling showed that WM (controlled attention), rather than STM (phonological loop), was related to growth in reading comprehension and reading fluency. The results support the notion that deficient growth in the executive component of WM underlies RD.