Memory Retrieval Processes Research Articles

No title, no theme: The joined neural space between speakers and listeners during production and comprehension of multi-sentence discourse

Speakers and listeners usually interact in larger discourses than single words or even single sentences. The goal of the present study was to identify the neural bases reflecting how the mental representation of the situation denoted in a multi-sentence discourse (situation model) is constructed and shared between speakers and listeners. An fMRI study using a variant of the ambiguous text paradigm was designed. Speakers (n = 15) produced ambiguous texts in the scanner and listeners (n = 27) subsequently listened to these texts in different states of ambiguity: preceded by a highly informative, intermediately informative or no title at all. Conventional BOLD activation analyses in listeners, as well as inter-subject correlation analyses between the speakers' and the listeners' hemodynamic time courses were performed. Critically, only the processing of disambiguated, coherent discourse with an intelligible situation model representation involved (shared) activation in bilateral lateral parietal and medial prefrontal regions. This shared spatiotemporal pattern of brain activation between the speaker and the listener suggests that the process of memory retrieval in medial prefrontal regions and the binding of retrieved information in the lateral parietal cortex constitutes a core mechanism underlying the communication of complex conceptual representations.

Unraveling the Electrophysiological Activity Behind Recognition Memory

Abstract. Traditionally, most event related potential (ERP) studies of memory retrieval have been reported during item-recognition tasks. Those studies lead to two well-known ERP memory components termed FN400 (familiarity) and LPC (recollection). Nevertheless, some critics have raised concerns regarding the actual meaning of that activity since it emerges as the result of contrasting two different memory traces (previously studied vs. seen for the first time), and it is registered after the target presentation. Therefore, they possibly depict operations not related to memory itself but some cognitive processes associated with recognition memory. Based on those critics, we propose an innovative approach to study electrophysiological activity underlying recognition memory. We compared two very similar tasks with only one of them requiring subjects to actively retrieve a “cue-target” pair of visual stimuli from memory, while the other task required subjects to recognize the target stimulus as equal/different to the cue. Because of this experimental manipulation, we assured that active memory retrieval processes take place between the presentation of the cue and the target stimuli for only one of the tasks. As a result, responses upon the targets can give us valuable information regarding ERP components associated with recognition based on memory retrieval. We found three components possibly related to brain computations necessary to achieve correct target recognition. A N200-like component linked to executive functions (inhibition) from frontal cortices, a P300-like component, related to the expectation of the target stimulus, and a P600-like component associated to recognition based on LTM retrieval. These results help us to understand the complexity behind ERP components associated with recognition memory.

A new tripartite landmark in human posterior cingulate cortex

Human brain imaging identifies the posterior cingulate cortex (PCC) as an anatomically and physiologically unique brain region. Structurally, the PCC has been reported as a central network hub of neocortical connectivity. Physiologically, the PCC regularly displays one of the highest metabolic rates in neocortex. However, despite these striking features, the function of PCC remains poorly understood. While the PCC is typically viewed as a key node of the default network (DN), owing to its suppressed activity during many attention demanding tasks, there’s little consensus regarding the contribution of PCC to behavior. For example, while human neuroimaging data suggest a role of PCC in episodic memory retrieval ‐ one of just a few tasks that increase PCC activity ‐ this view is inconsistent with non‐human primate physiology, which suggests a role of PCC in cognitive control. Central to this confusion is the varied and inconsistent anatomy/nomenclature used to define PCC. Across human studies, the term “PCC” is often used interchangeably with “precuneus” and/or “retrosplenial cortex”. It is therefore clear that a key requisite for progress in understanding PCC function is establishing reliable anatomical landmarks and associated nomenclature. From this foundation, the functional neuroanatomy of PCC can be built.With this goal in mind, we report on a systematic investigation of the macroanatomical features of the posteromedial cortex (PMC), which includes the posterior cingulate, precuneal, and retrosplenial cortices. Focusing chiefly on sulcal organization, we reliability identified several well‐known landmarks (i.e. marginal ramus of the cingulate sulcus (mcgs), parieto‐occipital sulcus, sub‐parietal sulcus, etc.). We also observed a high variability of other less studied sulci, such as those comprising the precuneal sulcal complex. However, we also identified a new reliable sulcus located inferior to the mcgs, which we term the inframarginal sulcus (ifrms). Interestingly, subsequent analyses of anatomical properties revealed the ifrms to display a unique profile of myelination, thickness, and cytoarchitecture. In addition, functional data also converged on the ifrms to highlight that this region, reflecting the dorsal aspect of the PCC, co‐localizes to the well known cognitive control network (CCN). Together, this tripartite convergence of macroanatomical, microanatomical, and functional properties suggests the ifrms to be a reliable and unique landmark within the PCC. This observation not only serves as a new landmark of PCC functional neuroanatomy, but also may help reconcile prior discrepancies between human and non‐human studies. This clarification points to PCC, particularly its dorsal aspect, as more engaged by cognitive control processes (i.e. CCN), as distinct from ventral PCC regions, being more engaged by memory retrieval processes (i.e. DN). Finally, the fact that a sulcus, which identifies multiple anatomical and functional cortical features, has remained un‐identified is striking considering neuroanatomists have been charting and labeling the outer surface of the human cerebrum for centuries and also begs the question ‐ how many other sulci have we yet to uncover?

The involvement of TRP channels in memory formation and task retrieval in a passive avoidance task in one-day old chicks.

An increase in the intracellular Ca2+ level in neurons is one of the main steps in the memory formation cascade. The increase results from extracellular Ca2+ influx by activation of ionotropic glutamate receptors and release from intracellular stores by the stimulation of IP3 receptors (IP3Rs) via group I metabotropic glutamate receptors (mGluR1/5). Recent data indicate an additional mechanism resulting in Ca2+ influx into neurons, triggered by intracellular signals that are directly connected to the activation of group I mGluRs. This influx occurs through transient receptor potential (TRP) channels, which are permeable to Na+, K+ and, mainly, Ca2+. These channels are activated by increases in intracellular Ca2+, diacylglycerol (DAC) and inositol 1,4,5-triphosphate (IP3) level resulting from a group I mGluR activation. The aim of the present study was to investigate the participation of TRP channels, especially from TRPC and TRPV groups, in memory consolidation and reconsolidation and memory retrieval processes in a passive avoidance task in one-day old chicks. TRP channels were blocked by the injection of the unspecific channel modulators SKF 96365 (2.5µl 30µM/hemisphere) and 2-APB (2.5µl 10µM/hemisphere) directly into the intermediate medial mesopallium (IMM) region of the chick brain immediately after initial training or after a reminder. The inhibition of specific TRP channels (TRPV1, TRPV3 or TRPC3) was achieved by the application of selective antibodies. Our results demonstrate that the inhibition of TRP channels by the application of both modulators disrupted memory consolidation, resulting in permanent task amnesia. The inhibition of the TRPV1, TRPC3 and TRPV3 channels by specific antibodies resulted in similar amnesia. Moreover, the inhibition of TRP channels by SKF 96365 and 2-APB at different time points after initial training or after the reminder also resulted in amnesia, indicating the role of TRP channels in memory retrieval. The inhibition of calcium influx through these channels resulted in permanent memory disruption, which suggests that the calcium signal generated by TRP channels is crucial for memory formation and retrieval processes. For the first time, the important role of TRPV3 channels in memory formation was demonstrated.

Reorganization of Functional Interactions in the Frontotemporal System of the Human Brain during Production of Russian Vowels

This report describe studies of the functioning of brain structures which are components of the frontotemporal system which is involved in the processes giving rise to speech and the organization of the mental lexicon. The studies address the question of whether it is possible, using functional tomography data, to discriminate the processes generating word forms into those carried out following rules (so-called regular forms) and those based on extracting forms from memory as whole units (so-called irregular forms). This was approached by carrying out experiments designed to identify how the origination of regular forms modulates the interaction between Broca’s area and two zones in the superior temporal gyrus of both hemispheres. It is suggested that when regular verbs are generated on the basis of symbolic rules (using a two-system approach), changes in interactions affect only the left hemisphere part of the system. Studies of cause effect relationships using dynamic causal modeling identified a relationship between the type of morphological process and the type of interaction between zones of the frontotemporal system. Thus, processes linked with generating regular forms, presuming construction of word forms from morphemes, are characterized by negative modulatory influences from the left zones of the superior temporal gyrus on activity in Broca’s area. These data support the view that the regularity effect seen in our previous studies of functional connectedness actually reflects the process of generation by rule and is supported by interactions between the left superior temporal cortex and Broca’s area. In addition, the generation of irregular verbs is characterized by an interaction between Broca’s area and the superior temporal gyrus in both hemispheres, which supports the suggestion that memory retrieval processes are involved.

Comparative study of protective effects of Cortexin, Cerebrolysin and Actovegin on memory impairment, cerebral circulation and morphological changes in the hippocampus of rats with chronic brain ischemia

To compare the effects of cortexin, cerebrolysin and actovegin on memory impairment, cerebral circulation and morphological changes in the hippocampus of rats with chronic brain ischemia. The study was conducted using male rats with chronic brain ischemia caused by stenosis of the common carotid arteries by 50%. Animals received cortexin (0,3; 1 or 3 mg/kg), cerebrolysin (0,8; 2,5 or 7,5 ml/kg) and actovegin (5 ml/kg) in two 10-day courses with 10 days of treatment break. The severity of cognitive impairment was evaluated using the Morris water maze, passive and active avoidance tests. Cerebral circulation using laser flowmetry and brain hippocampus structures were studied in the end of treatment. Cognitive impairment in animals with chronic brain ischemia was accompanied by the development of pathological changes in the CA1 and CA4 regions of the hippocampus. Administration of cortexin (1 and 3 mg/kg) and cerebrolysin (2.5 and 7.5 ml/kg) to rats with chronic brain ischemia had almost no effect on cerebral blood flow, but contributed to the improvement in memory formation and retrieval processes in the Morris water maze. The treatment effect was comparable for both drugs and persisted after 10 days of treatment break. Morphological assessment showed a decrease in the severity of pathological changes in the hippocampal regions. The course-administration of cortexin and cerebrolysin lead to a decrease in the severity of memory impairment and pathomorphological changes in the hippocampus in rats with chronic brain ischemia.

Prior Emotional Context Modulates Early Event-Related Potentials to Neutral Retrieval Cues.

Memory retrieval is thought to involve the reactivation of encoding processes. Previous fMRI work has indicated that reactivation processes are modulated by the residual effects of the prior emotional encoding context; different spatial patterns emerge during retrieval of memories previously associated with negative compared with positive or neutral context. Other research suggests that event-related potential (ERP) indicators of memory retrieval processes, like the left parietal old/new effect, can also be modulated by emotional context, but the spatial distribution and temporal dynamics of these effects are unclear. In the current study, we examined "when" emotion affects recognition memory and whether that timing reflects processes that come before and may guide successful retrieval or postrecollection recovery of emotional episodic detail. While recording EEG, participants (n = 25) viewed neutral words paired with negative, positive, or neutral pictures during encoding, followed by a recognition test for the words. Analyses focused on ERPs during the recognition test. In line with prior ERP studies, we found an early positive-going parietally distributed effect starting around 200 msec after retrieval-cue onset. This effect emerged for words that had been encoded in an emotional compared with neutral context (no valence differences), before the general old/new effect. This emotion-dependent effect occurred in an early time window, suggesting that emotion-related reactivation is a precursor to successful recognition.

Conditional automaticity: interference effects on the implicit memory retrieval process

Many studies have indicated that executing a secondary task during encoding has little influence on implicit memory (priming effect). However, relatively few studies have discussed the effect of interference on implicit memory during retrieval. Our previous studies found asymmetry between implicit encoding and retrieval processes, with the priming effect disrupted by retrieval interference. Therefore, the present study investigated why and how the priming effect is affected by interference at retrieval. We adopted a dual-task paradigm, with a lexical decision task as the memory task and an odd-even decision task as the interference task. The effect of interference during retrieval was assessed by comparing the performance in the interference condition with that in the full-attention condition. In Experiment 1, we observed that the priming effect was absent in the synchronous retrieval interference condition. In Experiment 2, asynchronous interference was also found to block the priming effect. To verify the assumption that the priming effect is sensitive to attentional resource competition during retrieval, we used two different manipulations (an extended stimulus interval in the dual-task paradigm, Experiment 3, and an interference inhibition manipulation, Experiment 4) known to reduce attentional distraction. In these experiments, the priming effect was protected from interference effects. We suggest that implicit memory retrieval could be regarded as a conditional automatic process that depends on a configuration of the cognitive system by attention and task sets. If the limited resources are occupied by another task, the implicit retrieval process can be impacted.

Exploitation vs. exploration—computational temporal and semantic analysis explains semantic verbal fluency impairment in Alzheimer's disease

Impaired Semantic Verbal Fluency (SVF) in dementia due to Alzheimer's Disease (AD) and its precursor Mild Cognitive Impairment (MCI) is well known. Yet, it remains open whether this impairment mirrors the breakdown of semantic memory retrieval processes or executive control processes. Therefore, qualitative analysis of the SVF has been proposed but is limited in terms of methodology and feasibility in clinical practice. Consequently, research draws no conclusive picture which of these afore-mentioned processes drives the SVF impairment in AD and MCI. This study uses a qualitative computational approach—combining temporal and semantic information—to investigate exploitation and exploration patterns as indicators for semantic memory retrieval and executive control processes. Audio SVF recordings of 20 controls (C, 66–81 years), 55 MCI (57–94 years) and 20 AD subjects (66–82 years) were assessed while groups were matched according to age and education. All groups produced, on average, the same amount of semantically related items in rapid succession within word clusters. Conversely, towards AD, there was a clear decline in semantic as well as temporal exploration patterns between clusters. Results strongly point towards preserved exploitation—semantic memory retrieval processes—and hampered exploration—executive control processes—in AD and potentially in MCI.

Telling a good story: The effects of memory retrieval and context processing on eyewitness suggestibility.

Witnesses are likely to describe a crime many times before testifying or encountering misinformation about that crime. Research examining the effect of retrieval on later suggestibility has yielded mixed results. LaPaglia and Chan manipulated whether misinformation was presented in a narrative or misleading questions, and they found that retrieval increased suggestibility when misinformation was presented in a narrative, but reduced suggestibility when the same misinformation was presented in questions. In the current study, we aimed to address why these differences occurred. Specifically, we examined whether contextual detail and narrative coherence during misinformation exposure influenced the relation between retrieval and suggestibility. Participants watched a robbery video and some were questioned about the event afterwards. They were then exposed to misinformation presented in a narrative (Experiment 1) or questions (Experiment 2) before taking a final memory test. Testing enhanced suggestibility when the misinformation phase reinstated contextual information of the event, but not when the misinformation phase included few contextual details–regardless of whether the misinformation was in a narrative or questions. In Experiment 3, disrupting narrative coherence by randomizing the order of contextual information eliminated retrieval-enhanced suggestibility. Therefore, context processing during the post-event information phase influences whether retrieval enhances or reduces eyewitness suggestibility.

Effects of the loss and reconstruction of molar occlusal support on memory retrieval and hippocampal neuron density in rats

PurposeAnimal experiments have shown that the loss of occlusal support causes impairments in spatial cognition. Many reports have focused on the memory encoding process, and only few studies have investigated the effect on memory retrieval. This study aimed to examine the effects of both the loss and reconstruction of occlusal support on the memory retrieval process and on the number of hippocampal pyramidal cells. MethodsThe experimental animals were divided into a molarless group, in which molars were extracted, a denture-wearing molarless group with experimental dentures inserted after molar extraction, and a control group. Radial maze trials were performed for 20 consecutive days (acquisition phase). The rats were tested on long-term memory retention following the acquisition phase in eight trials every five days, and in an additional trial 20 days later (probe phase). ResultsThe denture-wearing molarless group showed higher levels of spatial learning and memory than the molarless group. There were no significant differences in memory retrieval during the probe phase between the denture-wearing molarless and the control group. The molarless group showed significantly worse spatial learning and memory and had fewer neurons in the hippocampus than the control group. ConclusionsOur results suggest that the loss of occlusal support decreases the number of pyramidal cells in the hippocampus and impairs memory decoding and retrieval. However, this effect is suppressed by the reconstruction of occlusal support.

Chapter 12 - The lateral prefrontal cortex and human long-term memory

Recent research has demonstrated that the lateral prefrontal cortex is extensively involved in human memory, including working memory processes that support retention of information across short delays, and episodic long-term memory encoding and retrieval processes. This chapter reviews results from neuroimaging studies of memory, from noninvasive brain stimulation studies of memory, and from studies of memory in patients with prefrontal lesions. The available evidence is consistent with the idea that different prefrontal regions implement cognitive or executive control processes that support working memory and episodic long-term memory encoding and retrieval.

Drug-free and context-dependent locomotor hyperactivity in DBA/2 J mice previously treated with repeated cocaine: Relationship with behavioral sensitization and role of noradrenergic receptors

Drug-associated contexts and discrete cues can trigger motivational states responsible for drug-seeking behavior and relapse. In preclinical research, drug-free conditioned hyperactivity has been used to investigate the expression of memories associated with psychostimulant drug effects. Addictive drugs can produce long-lasting sensitization to their psychomotor actions, a phenomenon known as behavioral sensitization. The neuroplasticity underlying behavioral sensitization appears to be involved in pathological drug pursuit and abuse. In the present study we evaluated drug-free, context-dependent hyperactivity in DBA/2 J mice previously treated with cocaine and we explored whether this conditioned effect was related to behavioral sensitization. Given the role of noradrenergic (NA) neurotransmission in memory retrieval, consolidation and reconsolidation processes, we also investigated whether conditioned hyperactivity in a drug-free state was mediated by NA receptors. Animals underwent a sensitization protocol with six cocaine injections (0, 5, 10 or 20 mg/kg) paired to a particular floor cue. Three days after this sensitization phase, all animals were exposed to the same familiar floor environment without drug treatment. A second test with an unfamiliar floor was conducted 24 h later. Conditioned hyperactivity was also explored after one or three cocaine pairings and was evaluated for its duration (with repeated familiar vs. unfamiliar floor tests). In a series of pharmacological experiments, we evaluated the effects propranolol (a non-selective antagonist of β1- and β2-receptors) and prazosin (α1-receptor antagonist) on conditioned hyperactivity. Cocaine treatment produced both robust sensitization and drug-free conditioned hyperactivity, an effect that lasted up to 17 days (with cocaine 20 mg/kg). A significant correlation between the magnitude of cocaine sensitization and the level of conditioned hyperactivity was found. Propranolol, but not prazosin, blocked context-dependent hyperlocomotion in a drug-free state. Our data, together with a vast body of literature, indicate that the NA system plays a key role in the retrieval and behavioral expression of drug-associated memories.

Retrieval process of overgeneral memory and the capture and executive control hypothesis: using Autobiographical Memory Test with thought sampling

ABSTRACTThe retrieval process for underlying overgeneral autobiographical memory remains unclear. In this study, we identified what leads to self-referential and categoric thoughts and examined the influence error-monitoring ability has on the reporting of categoric memories. We also examined whether cue self-relevance and/or executive control task performance are related to the number of specific memories reported. Using thought sampling, 94 college students completed the Autobiographical Memory Test, as well as a verbal fluency task and a depression scale. The results indicated that depressive symptoms and negative highly self-relevant cues were associated with self-referential/categoric thoughts during memory retrieval. Further, preceding self-referential/categoric thoughts and low error-monitoring ability predicted immediate after-reporting of categoric memories. Simultaneously, highly self-relevant cues and executive control task performance predicted the reporting of many specific memories. Subdividing the retrieval process and examining the process involved in depression are essential.

Subjectively-defined optimal/non-optimal time of day modulates controlled but not automatic retrieval processes in verbal memory.

Performance for controlled, resource-demanding retrieval in episodic memory has been consistently found to be better at an optimal compared with non-optimal time of the day, evidencing a synchrony effect. However, performance in memory tasks in which retrieval is mostly based on automatic processes was inconclusively found either to be better at a non-optimal time of day or independent of synchrony effects. A caveat in most prior studies is that optimal/non-optimal time of day is based on morningness-eveningness composite scores derived from chronotype questionnaires, which might not efficiently predict subjectively-defined cognitive efficiency periods. An additional caveat is that separate tasks are used to assess explicit and implicit retrieval in verbal memory. Indeed, no task is process-pure, and both controlled and automatic retrieval processes may potentially contribute to retrieval scores in different types of memory tasks. In the present study, we investigated the impact of individually defined subjective optimal/non-optimal time of day on verbal memory retrieval, using an adaptation of the Process-Dissociation Procedure that allows estimating the respective contributions of automatic and controlled memory retrieval processes within the same memory task. Our results disclose a higher involvement of controlled processes at subjectively optimal compared with non-optimal time of day, but no differences for automatic processes. Synchrony effects and subjectively-defined peaks and troughs of performance for controlled components of memory retrieval should be considered in the evaluation of episodic memory.

Towards an Automatic Analysis of the Semantic Verbal Fluency for Cognitive Assessment

Semantic verbal fluency (SVF) tests are routinely used in screening for mild cognitive impairment (MCI) and seem to be highly sensitive to cognitive changes [1]. In this task, participants name as many items of a semantic category under a time constraint. SVF can be considered as a multifactorial task, comprising both semantic memory retrieval and executive control processes. However, clinicians measure task performance manually only by summing the number of correct words and errors. More fine-grained variables add valuable information to clinical assessment, but are time-consuming. Therefore, the aim of this study is to investigate whether automatic speech analysis of the SVF could provide these as accurate as manual and thus, support qualitative screening of neurocognitive impairment. Furthermore, we examined the technologic feasibility of automatically assessing the SVF task – via a telephone-based solution for potential remote frontline prescreening of cognitive impairments [2]. We will present SVF data which was collected from 95 older people with MCI (n=47), Alzheimer’s or related dementias (ADRD; n=24) and healthy controls (HC; n=24). Speech was recorded through a mobile tablet device using the built-in microphone. All data was annotated manually and automatically with the named words, clusters and switches. The obtained metrics were validated using a classifier to distinguish HC, MCI and ADRD. Afterwards to simulate telephone conditions, the recordings were downsampled to a lower sampling rate. Automatically extracted clusters and switches were highly correlated (r=0.9) with manually established values, and performed as well on the classification task separating healthy controls from persons with Alzheimer’s (AUC=0.939) and MCI (AUC=0.758) [3]. The downsampled quality obtained similar encouraging results. We observe a relatively low word error rate of 33% despite phone-quality speech samples. The automated classification pipeline performs equally well compared to the classifier trained on manual transcriptions of the same speech data. Our results indicate SVF as a prime candidate for inclusion into an automated telephone-screening system and that it is possible to automate fine-grained analyses of this task for the assessment of cognitive decline.

A study of retrieval processes in action memory for school-aged children: the impact of recall period and difficulty on action memory

ABSTRACTResearch in action memory for adults has shown that enacted encoding is not only retrieved more frequently but is also faster in comparison to verbal encoding. The aim of this study was to investigate retrieval processes in terms of recall period and recall difficulty for different encoding conditions in school-aged children (8-, 10-, 12-, 14-years old). The participants studied verbal tasks, subject-performed tasks and experimenter-performed tasks, and received immediate and final free-recall tests. The results revealed that older children not only outperformed younger children in terms of accuracy but also outpaced them in all recall periods. Moreover, recalls of subject-performed tasks and experimenter-performed tasks were better and faster compared with verbal encoding on both types of recall test, by increasing throughout the recall periods. These results are discussed in terms of memory strategies and information processing methods. Pedagogic implications for the use of action memory in children's learning are also considered.

On the sensitivity of event-related fields to recollection and familiarity

The sensitivity of event-related potentials (ERPs) to the processes of recollection and familiarity has been explored extensively, and ERPs have been used subsequently to infer the contributions these processes make to memory judgments under a range of different circumstances. It has also been shown that event-related fields (ERFs, the magnetic counterparts of ERPs) are sensitive to memory retrieval processes. The links between ERFs, recollection and familiarity are, however, established only weakly. In this experiment, the sensitivity of ERFs to these processes was investigated in a paradigm used previously with ERPs. An early frontally distributed modulation varied with memory confidence in a way that aligns it with the process of familiarity, while a later parietally distributed modulation tracked subjective claims of recollection in a way that aligns it with this process. These data points strengthen the argument for employing ERFs to assess the contributions these processes can make to memory judgments, as well as for investigating the nature of the processes themselves.

Collective Narcissism: Americans Exaggerate the Role of Their Home State in Appraising U.S. History

Collective narcissism—a phenomenon in which individuals show excessively high regard for their own group—is ubiquitous in studies of small groups. We examined how Americans from the 50 U.S. states (N = 2,898) remembered U.S. history by asking them, “In terms of percentage, what do you think was your home state’s contribution to the history of the United States?” The mean state estimates ranged from 9% (Iowa) to 41% (Virginia), with the total contribution for all states equaling 907%, indicating strong collective narcissism. In comparison, ratings provided by nonresidents for states were much lower (but still high). Surprisingly, asking people questions about U.S. history before they made their judgment did not lower estimates. We argue that this ethnocentric bias is due to ego protection, selective memory retrieval processes involving the availability heuristic, and poor statistical reasoning. This study shows that biases that influence individual remembering also influence collective remembering.

Can't get it out of my mind: A systematic review of predictors of intrusive memories of distressing events.

Intrusive memories, when persistent and distressing, are theorized to underlie a range of transdiagnostic psychological symptoms and associated impairment. However, little is known about factors predicting the development and persistence of intrusive memories. The aim of this systematic review is to evaluate the literature on pre-event, event-based, and post-event predictors of intrusive memories. A systematic review was conducted, searching for studies that examined intrusive, event-based memories. One hundred and six articles were identified from PsycInfo, PubMed, and Medline databases. Experimental and prospective studies with clinical (N = 14) and nonclinical (N = 92) samples were critically reviewed, provided the inclusion of an analogue stressor with nonclinical samples, and that intrusive memories frequency and/or distress were assessed as primary dependent variables. Pre-existing psychopathology and pre-event appraisal style appear to predict intrusive memories (small to medium effects), whereas trait dissociation did not predict intrusive memories. Of studies examining event-based predictors, higher data-driven processing appears to predict intrusive memories with generally large effects. Post-event negative appraisals consistently predicted intrusive memories (medium to large effects), and preliminary evidence suggests higher post-event conceptual processing predicting fewer intrusive memories. This review synthesizes findings regarding a broad range of pre-event, event-based, and post-event factors that may influence the development of intrusive memories. Methodological issues of current paradigms and the lack of emphasis on memory retrieval processes limit our understanding of what predicts intrusive memory persistence. These limitations are particularly important given that individuals typically seek treatment for distressing intrusive memories once a memory has been fully consolidated, where retrieval processes are of utmost importance. (PsycINFO Database Record