Evaluation of the evidence for the trauma and fantasy models of dissociation

The relationship between a reported history of trauma and dissociative symptoms has been explained in 2 conflicting ways. Pathological dissociation has been conceptualized as a response to antecedent traumatic stress and/or severe psychological adversity. Others have proposed that dissociation makes individuals prone to fantasy, thereby engendering confabulated memories of trauma. We examine data related to a series of 8 contrasting predictions based on the trauma model and the fantasy model of dissociation. In keeping with the trauma model, the relationship between trauma and dissociation was consistent and moderate in strength, and remained significant when objective measures of trauma were used. Dissociation was temporally related to trauma and trauma treatment, and was predictive of trauma history when fantasy proneness was controlled. Dissociation was not reliably associated with suggestibility, nor was there evidence for the fantasy model prediction of greater inaccuracy of recovered memory. Instead, dissociation was positively related to a history of trauma memory recovery and negatively related to the more general measures of narrative cohesion. Research also supports the trauma theory of dissociation as a regulatory response to fear or other extreme emotion with measurable biological correlates. We conclude, on the basis of evidence related to these 8 predictions, that there is strong empirical support for the hypothesis that trauma causes dissociation, and that dissociation remains related to trauma history when fantasy proneness is controlled. We find little support for the hypothesis that the dissociation-trauma relationship is due to fantasy proneness or confabulated memories of trauma.     

Risk assessment behaviors associated with corticosterone trigger the defense reaction to social isolation in rats: role of the anterior cingulate cortex

The extent to which the hypothalamic-pituitary-adrenal axis is activated by short-term and long-term consequences of stress is still open to investigation. This study aimed to determine (i) the correlation between plasma corticosterone and exploratory behavior exhibited by rats subjected to the elevated plus maze (EPM) following different periods of social isolation, (ii) the effects of the corticosterone synthesis blocker, metyrapone, on the behavioral consequences of isolation, and (iii) whether corticosterone produces its effects through an action on the anterior cingulate cortex, area 1 (Cg1). Rats were subjected to 30-min, 2-h, 24-h, or 7-day isolation periods before EPM exposure and plasma corticosterone assessments. Isolation for longer periods of time produced greater anxiogenic-like effects on the EPM. However, stretched attend posture (SAP) and plasma corticosterone concentrations were increased significantly after 30?min of isolation. Among all of the behavioral categories measured in the EPM, only SAP positively correlated with plasma corticosterone. Metyrapone injected prior to the 24?h isolation period reversed the anxiogenic effects of isolation. Moreover, corticosterone injected into the Cg1 produced a selective increase in SAP. These findings indicate that risk assessment behavior induced by the action of corticosterone on Cg1 neurons initiates a cascade of defensive responses during exposure to stressors.     

Accuracy of Effect Size Estimates From Published Psychological Experiments Involving Multiple Trials

The reporting of exaggerated effect size estimates may occur either through researchers accepting statistically significant results when power is inadequate and/or from repeated measures approaches aggregating, averaging multiple items, or multiple trials. Monte-Carlo simulations with input of a small, medium, or large effect size were conducted on multiple items or trials that were either averaged or aggregated to create a single dependent measure. Alpha was set at the .05 level, and the trials were assessed over item or trial correlations ranging from 0 to 1. Simulations showed a large increase in observed effect size averages and the power to accept these estimates as statistically significant increased over numbers of trials or items. Overestimation effects were mitigated as correlations between trials increased but still remained substantial in some cases. The implications of these findings for meta-analyses and different research scenarios are discussed.     

Psychogenic amnesia – A malady of the constricted self

Autobiographical–episodic memory is the conjunction of subjective time, autonoetic consciousness and the experiencing self. Understanding the neural correlates of autobiographical–episodic memory might therefore be essential for shedding light on the neurobiology underlying the experience of being an autonoetic self. In this contribution we illustrate the intimate relationship between autobiographical–episodic memory and self by reviewing the clinical and neuropsychological features and brain functional imaging correlates of psychogenic amnesia – a condition that is usually characterized by severely impaired retrograde memory functioning, in absence of structural brain damage as detected by standard imaging. We demonstrate that in this disorder the autobiographical–episodic memory deficits do not exist in isolation, but occur with impairments of the autonoetic self-consciousness, emotional processing, and theory of mind or executive functions. Furthermore functional and metabolic brain alterations involving regions that are agreed upon to exert crucial roles in memory processes were frequently found to accompany the psychogenic memory “loss”.     

The effects of distributed and focused attention on rapid scene categorization

It has been argued that distributed attention facilitates the rapid extraction of summary statistics that underpins rapid scene categorization. We directly examined this hypothesis by investigating whether distributed or focused attention is more compatible with the extraction of both summary statistics (Experiment 1) and semantic scene information (Experiments 2–4). Experiment 1 replicated Chong and Treisman’s (2005a) result that mean circle size judgments are more compatible with a distributed attention task than a focused attention task. Experiment 2 investigated whether this finding extends to simple scene categorization by replacing the averaging task with an animal detection task. Consistent with Experiment 1, the ability to detect the presence of an animal was more compatible with a distributed attention task than a focused attention task. Experiments 3 and 4 addressed whether distributed attention influences scene categorization tasks. When observers were asked to classify scenes based on their basic level (e.g., beach or forest; Experiment 3), there was no statistically significant difference between focused and distributed attention task conditions; however, superordinate level categorization (e.g., natural or manmade; Experiment 4) was faster when combined with a task requiring distributed attention compared to a task requiring focused attention.     

Elite sport is not an additional source of distress for adolescents with high stress levels

This study examined whether participation in elite sport interacts with stress in decreasing or increasing symptoms of depression and anxiety among adolescents, and further, whether the interplay between participation in high-performance sport and stress is related to the perceived quality of sleep. 434 adolescents (278 girls, 156 boys; age: M = 17.2 yr.) from 15 "Swiss Olympic Sport Classes" and 9 conventional classes answered a questionnaire and completed a 7-day sleep log. Analyses of covariance showed that heightened stress was related to more depressive symptoms and higher scores for trait-anxiety. Moreover, those classified as having poor sleep by a median split cutoff reported higher levels of depressive symptoms. No significant (multivariate) main effects were found for high-performance sport athletes. Similarly, no significant two- or three-way interaction effects were found. These results caution against exaggerated expectations concerning sport participation as a stress buffer. Nevertheless, participation in high-performance sport was not found to be an additional source of distress for adolescents who reported high stress levels despite prior research that has pointed toward such a relationship.     

Deconstructing antenatal depression: What is it that matters for neonatal behavioral functioning?

This prospective study examined the variability within clinical characteristics of antenatal maternal depression and cortisol levels for associations with newborn infant behavior using the Neonatal Behavioral Assessment Scale (NBAS; T.B. Brazelton, 1984 ). Participants were 81 pregnant women at risk for perinatal depression given their histories of depression prior to pregnancy. We took into consideration not only whether the woman experienced antenatal depression but also whether the depression met diagnostic criteria and variability in timing (onset and occurrence) of antenatal depression and symptom severity. Infants of mothers who became depressed during pregnancy scored less optimally on a subset of the NBAS scales, specifically those scales related to infant neuroregulation. Among the clinical characteristics of depression, the fetus' overall exposure to mothers' depression (reflected in the mean) was most often and most strongly associated with NBAS scales. In terms of timing, third‐trimester exposure was significantly related to newborn behavior. The findings are discussed within the S.H. Goodman and I.H. Gotlib ( 1999 ) model for transmission of psychopathology to offspring of depressed mothers.