Primacy (and recency) effects in delayed recognition of items from instances of repeated events.

In repeated-event paradigms where participants are asked to recall details of a sequence of similar instances they viewed/experienced previously, more accurate details are typically recalled from the first and final instances (i.e., long-term primacy and recency effects). Participants likely encode distinct attributes of details of the boundary instances that subsequently facilitate source monitoring. To date, most repeated event research has measured memory performance via free-/cued-recall paradigms; we examined delayed memory for repeated events using the recognition paradigm. In two preregistered experiments, participants viewed four videos, and after a delay completed a recognition task. In Experiment 1 (N = 168, between-subjects), participants decided whether an item was old (i.e., presented in any video) or new, or whether an item was presented in video 1/2/3/4 or was new. In Experiment 2 (N = 160, within-subjects), the old/new decision was followed by an instance attribution decision. Old items were recognised faster in the old/new task compared to the instance-attribution task. In the instance-attribution task, items from the boundary instances were accurately attributed faster compared to items from the middle instances. We found further evidence for primacy (and recency) effects in measures of confidence, memory judgments, recognition accuracy and discriminability, and confidence-accuracy calibration.

Counterfactual imagination impairs memory for true actions: EEG and behavioural evidence.

Imagined events can be misremembered as experienced, leading to memory distortions. However, less is known regarding how imagining counterfactual versions of past events can impair existing memories. We addressed this issue, and used EEG to investigate the neurocognitive processes involved when retrieving memories of true events that are associated with a competing imagined event. Participants first performed simple actions with everyday objects (e.g., rolling dice). A week later, they were shown pictures of some of the objects and either imagined the same action they had originally performed, or imagined a counterfactual action (e.g., stacking the dice). Subsequent tests showed that memory for performed actions was reduced after counterfactual imagination when compared to both veridical imagination and a baseline condition that had not been imagined at all, providing novel evidence that counterfactual imagination impairs true memories beyond simple forgetting over time. ERPs and EEG oscillations showed evidence of separate processes associated with memory retrieval versus post-retrieval processes that were recruited to support recall of memories that were challenging to access. The findings show that counterfactual imagination can cause impairments to sensorimotor-rich event memories, and provide new evidence regarding the neurocognitive mechanisms that are recruited when people need to distinguish memories of imagined versus true events.

Unraveling the brain mechanisms of source monitoring with non-invasive brain stimulation: A systematic review.

Background/Objective: Source monitoring refers to the ability to determine the source of memories and encompasses three subprocesses: internal source monitoring, reality monitoring, and external source monitoring. Neuroimaging studies provide valuable insights about neural correlates of source monitoring, but the causal relationship between brain and behavior is lacking. This study aimed to identify brain circuits involved in source monitoring by synthesizing the effects of brain stimulation on source monitoring as a function of the targeted brain regions or circuits. Method: We conducted a systematic review of interventional studies that have examined the effects of brain stimulation on source monitoring across six databases. The principal outcome was the difference of source monitoring performance between active and control stimulation conditions. Results: 23 studies (920 healthy participants and 54 patients with schizophrenia) were included. Our findings revealed the involvement of i) the lateral prefrontal and temporoparietal cortices in internal source monitoring, ii) the medial prefrontal and temporoparietal cortices in reality monitoring, and iii) the precuneus and the left angular gyrus in external source monitoring. Conclusions: These findings deepen our understanding of the brain mechanisms of source monitoring and highlight specific stimulation targets to alleviate source monitoring deficits.

Self-monitoring deficits in schizophrenia: A cross-sectional study of the underlying cognitive mechanisms.

BACKGROUND: People diagnosed with schizophrenia share underlying cognitive deficits in self-monitoring (i.e., identifying the source of self-generated behaviours). This study aimed to investigate whether self-monitoring deficits in schizophrenia are due to a cognitive response bias towards external perceptions or a reduced discriminability of imagined and performed actions. We hypothesised that self-monitoring deficits in individuals with schizophrenia are primarily driven by bottom-up processes, leading to a compromised ability to discriminate between internally generated behaviours as opposed to a cognitive response bias towards performed actions. METHODS: We recruited 333 participants, including 192 with schizophrenia and 141 healthy controls. As part of the Action-Memory Task, participants were instructed to either imagine or physically perform 36 different actions, half of which were presented as pictograms and half as text. In the test phase, participants indicated whether they had performed or imagined each action, whether it appeared in text or pictogram, or whether it was a new action. Using Signal Detection Theory, the study primarily analysed group differences in discriminability and response-bias. RESULTS: Participants with schizophrenia made significantly more self-monitoring errors than healthy controls. This was primarily due to significantly lower sensitivity, but not a response bias. Whereas recognition memory errors were driven by both lower sensitivity and a response bias. CONCLUSIONS: The findings suggest that self-monitoring in schizophrenia was specifically impaired by a compromised discriminability of imagined and performed events and an inability to appropriately compensate by adjusting decision-thresholds. Implications on the role of bottom-up and top-down cognitive mechanisms are discussed.

Remember walking in their shoes? The relation of self-referential source memory and emotion recognition.

Deficits in the ability to read the emotions of others have been demonstrated in mental disorders, such as dissociation and schizophrenia, which involve a distorted sense of self. This study examined whether weakened self-referential source memory, being unable to remember whether a piece of information has been processed with reference to oneself, is linked to ineffective emotion recognition. In two samples from a college and community, we quantified the participants' ability to remember the self-generated versus non-self-generated origins of sentences they had previously read or partially generated. We also measured their ability to read others' emotions accurately when viewing photos of people in affect-charged situations. Multinomial processing tree modelling was applied to obtain a measure of self-referential source memory that was not biased by non-mnemonic factors. Our first experiment with college participants revealed a positive correlation between correctly remembering the origins of sentences and accurately recognising the emotions of others. This correlation was successfully replicated in the second experiment with community participants. The current study offers evidence of a link between self-referential source memory and emotion recognition.

PEPPR: A post-encoding pre-production reinstatement model of dual-list free recall.

Recent events are easy to recall, but they also interfere with the recall of more distant, non-recent events. In many computational models, non-recent memories are recalled by using the context associated with those events as a cue. Some models, however, do little to explain how people initially activate non-recent contexts in the service of accurate recall. We addressed this limitation by evaluating two candidate mechanisms within the Context-Maintenance and Retrieval model. The first is a Backward-Walk mechanism that iteratively applies a generate/recognize process to covertly retrieve progressively less recent items. The second is a Post-Encoding Pre-Production Reinstatement (PEPPR) mechanism that formally implements a metacognitive control process that reinstates non-recent contexts prior to retrieval. Models including these mechanisms make divergent predictions about the dynamics of response production and monitoring when recalling non-recent items. Before producing non-recent items, Backward-Walk cues covert retrievals of several recent items, whereas PEPPR cues few, if any, covert retrievals of that sort. We tested these predictions using archival data from a dual-list externalized free recall paradigm that required subjects to report all items that came to mind while recalling from the non-recent list. Simulations showed that only the model including PEPPR accurately predicted covert recall patterns. That same model fit the behavioral data well. These findings suggest that self-initiated context reinstatement plays an important role in recall of non-recent memories and provides a formal model that uses a parsimonious non-hierarchical context representation of how such reinstatement might occur.

Anomalies of imagination and development of psychosis: A phenomenological account.

In 20th century psychiatry, various disturbances of imagination were discussed in the context of schizophrenia. Today, these notions have almost completely vanished from mainstream psychopathology. However, recent work has suggested that specific phenomena within this area have a relevance for differential diagnosis and early detection of psychosis. This paper first provides an overview of 20th century psychopathological literature, as well as more recent neurocognitive studies, addressing disturbances of imagination and their role for symptom formation in schizophrenia. It then discusses recent empirical investigations of subjective anomalies of imagination in schizophrenia-spectrum disorders and suggests a clinical-phenomenological account of their role in the development of psychotic symptoms. Empirically and conceptually, these subjective anomalies are linked with disturbances of basic self. Patients' descriptions of the development of their anomalous experiences and symptoms indicate that increased spatial (object-like) articulation and instability of the first-personal manifestation of imaginative experience can be involved in the emergence of delusions and hallucinatory phenomena. Finally, a potential link between subjective anomalies of imagination and the neurocognitive construct of source monitoring deficits is discussed.

Cognitive correlates of auditory hallucinations in schizophrenia spectrum disorders.

Auditory hallucinations (AHs) are one of the central symptoms of schizophrenia spectrum disorders (SSD). Current cognitive models of AH implicate source monitoring, top-down processes, and inhibitory control. However, research combining these processes is limited. Our study aimed to examine how source monitoring bias, top-down processes, and inhibitory control contribute to AHs in individuals with SSD. Eighty seven patients (aged 18-45 years) with SSD were included in the analyses. Participants completed cognitive tasks assessing source monitoring (Action Memory Task), top-down processes (False Perception Task; FPT), and inhibitory control (Auditory Go/NoGo task). AH was positively associated with response bias on the FPT. Correlations between AH and the other cognitive tasks were nonsignificant. Source monitoring errors correlated positively with response bias measures and negatively with Hits on the FPT. PANSS total score was positively correlated with source monitoring bias and False Alarms on the Go/NoGo task. The severity of disorganized symptoms was related to Source Monitoring Errors and False Alarms in the Go/NoGo task. Negative symptoms were associated with Hits and False Alarms in the Go/NoGo task. Future studies are necessary to further elucidate the relationships between different cognitive processes that may be related to clinical symptoms of psychosis.

Preference for cheap-and-easy memory verification strategies is strongest among people with high memory distrust.

When choosing strategies for verifying one's memory, people are more influenced by the perceived cost of using a strategy than by its likelihood of yielding reliable information (i.e., cheap-strategy bias). The current preregistered study investigated whether people with high memory distrust are less likely to exhibit this bias than their low memory distrust counterparts. Participants (N = 535) imagined a scenario in which they witnessed an accident and were then led by friends to question their memories about the accident. Participants had to propose five strategies for verifying that particular memory. Following this, they rated each strategy's cost, reliability, and their likelihood of using it, as well as completing two validated measures of trait memory distrust. Contrary to our prediction, compared with participants with low memory distrust, participants with higher memory distrust exhibited a larger cheap-strategy bias. Follow-up analyses suggested that compared with memory-trusters, memory distrusters' strategy choices were more influenced by a strategy's perceived cost, and less influenced by its perceived reliability. Our results suggest that people who are more skeptical about their memories may be more cynical about the worthwhileness of verifying their memory, which could make them especially susceptible to misinformation acceptance and false memory creation.

The temporal development of memory processes in source monitoring: An investigation with mouse tracking.

The present study investigated whether we first remember an item (e.g., a word itself) and then its source (e.g., position on the screen) or whether the retrieval of item and source information can (partially) overlap. Participants were tested on the source either in immediate sequence to item recognition (as standard in source-monitoring research) or following as a separate block after full completion of the item recognition test to separate these processes in time, providing a baseline. Using the mouse-tracking procedure during the item and source tests, we analyzed how item and source decisions unfolded qualitatively over time. Despite no significant difference in the aggregated trajectory curvatures, more thorough analyses based on the individual trajectories revealed differences across the test formats. In the standard format, trajectories were less curved in the source than in the item test. In contrast, in the blocked format, this difference was in the other direction with source showing more curved trajectories than item. Alternative interpretations of mouse-trajectory curvatures on the source-monitoring paradigm and what their difference may imply for item and source processing are discussed.

Don't blame yourself: Conscious source monitoring modulates feedback control during speech production.

Sensory feedback plays an important role in speech motor control. One of the main sources of evidence for this is studies in which online auditory feedback is perturbed during ongoing speech. In motor control, it is therefore crucial to distinguish between sensory feedback and externally generated sensory events. This is called source monitoring. Previous altered feedback studies have taken non-conscious source monitoring for granted, as automatic responses to altered sensory feedback imply that the feedback changes are processed as self-caused. However, the role of conscious source monitoring is unclear. The current study investigated whether conscious source monitoring modulates responses to unexpected pitch changes in auditory feedback. During the first block, some participants spontaneously attributed the pitch shifts to themselves (self-blamers) while others attributed them to an external source (other-blamers). Before Block 2, all participants were informed that the pitch shifts were experimentally induced. The self-blamers then showed a reduction in response magnitude in Block 2 compared with Block 1, while the other-blamers did not. This suggests that conscious source monitoring modulates responses to altered auditory feedback, such that consciously ascribing feedback to oneself leads to larger compensation responses. These results can be accounted for within the dominant comparator framework, where conscious source monitoring could modulate the gain on sensory feedback. Alternatively, the results can be naturally explained from an inferential framework, where conscious knowledge may bias the priors in a Bayesian process to determine the most likely source of a sensory event.

Sources and destinations of misattributions in recall of instances of repeated events.

Repeated experience of events promotes schema formation. Later activation of the schema facilitates recall of the general structure of the events, whereas attribution of details to instances requires systematic decision-making based on detail characteristics. For repeated events, source monitoring may be less effective due to the similarity and interference of details across instances and consequently result in source attribution errors. To date, researchers have examined aggregated misattributions across instances and have found that misattributions are more frequent in the middle than in the boundary instances. In this study, we investigated the trajectories of misattributions using data from six studies (N = 633), where participants recalled repeated interactive marketing-themed events (Study 1), mock-crime filmed events (Study 2), stories (Study 3), and categorized word lists (Studies 4-6). The patterns confirmed the expected primacy and recency effects, showing fewer misattributions from and to the boundary instances relative to the middle instances. In addition, the patterns indicated proximity effects: Confusions more frequently occurred across adjacent instances and gradually decreased for instances that were further apart from the source. Our findings suggest that detail characteristics that form the basis of source attribution decisions provide information about the relative position of instances in repeated events, where the boundary instances serve as anchors, and where confusion relatively easily occurs across neighbouring instances. In line with context-based models of memory, our findings indicate that a higher-level organization of repeated events that emerges at encoding guides retrieval and source monitoring decisions.

Remedying the Metamemory Expectancy Illusion in Source Monitoring: Are there Effects on Restudy Choices and Source Memory?

Metamemory monitoring, study behavior, and memory are presumably causally connected. When people misjudge their memory, their study behavior should be biased accordingly. Remedying metamemory illusions should debias study behavior and improve memory. One metamemory illusion concerns source memory, a critical aspect of episodic memory. People predict better source memory for items that originated from an expected source (e.g., toothbrush in a bathroom) rather than an unexpected source (e.g., shampoo in a kitchen), whereas actual source memory shows the opposite: an inconsistency effect. This expectancy illusion biases restudy choices: Participants restudy more unexpected than expected source-item pairs. The authors tested the causal relationships between metamemory and source memory with a delay and a source-retrieval attempt between study and metamemory judgment to remedy the expectancy illusion and debias restudy choices. Debiased restudy choices should enhance source memory for expected items, thereby reducing the inconsistency effect. Two groups studied expected and unexpected source-item pairs. They made metamemory judgments and restudy choices immediately at study or after delay, restudied the selected pairs, and completed a source-monitoring test. After immediate judgments, participants predicted better source memory for expected pairs and selected more unexpected pairs for restudy. After delayed judgments, participants predicted a null effect of expectancy on source memory and selected equal numbers of expected and unexpected pairs. Thus, the expectancy illusion was partially remedied and restudy choices were debiased. Nevertheless, source memory was only weakly affected. The results challenge the presumed causal relationships between metamemory monitoring, study behavior, and source memory.

False recalls, but not false recognitions, at the DRM paradigm are increased in subjects reporting insomnia symptoms: An online study.

BACKGROUND: In insomnia, poor sleep is accompanied by several cognitive impairments affecting prefrontal functioning that could affect source-monitoring processes and contribute to false memories production. By using a modified version of the Deese-Roediger-McDermott paradigm (DRM), we previously found that individuals suffering from insomnia produced more false memories than good sleepers adopting a free-recall task, especially for sleep-related stimuli. However, whether poor sleep affects false memory production in a task-dependent manner (i.e., free recall or recognition) remains unclear. METHODS: Through an online research method, we adopted the classical DRM paradigm to investigate the production of false recalls and false recognitions in 32 subjects referring insomnia symptoms (IN group) and 37 good sleepers (GS group), addressing also executive functioning and source monitoring ability in both groups. RESULTS: Compared to the GS group, the IN group produced more false memories (p = .002) and intrusions (p = .004) at the free recall task and showed a lower working memory index (p = .008). No between-groups differences emerged at the recognition task. Correlational analysis revealed significant associations between DRM performance, executive functioning and source monitoring (SM) variables. Moreover, false recalls were predicted by being in the presence of insomnia symptoms (p = .012) and intrusions by the number of correct responses to the Stroop task (p = .051) and SM task (p = .015), as well as by the presence of insomnia symptoms (p = .003). CONCLUSIONS: Our data show that the presence of insomnia symptoms can influence false memories production. Furthermore, the evidence that free recall is more affected than recognition suggests that poor sleep mainly affects performance at more cognitively demanding tasks. Finally, correlational and regression analyses support the hypothesis of a link between false memories production and both the presence of insomnia symptoms and executive functioning impairments.

Coping with high advertising exposure: a source-monitoring perspective.

Consumers are exposed to large amounts of advertising every day. One way to avoid being manipulated is to monitor the sources of persuasive messages. In the present study it was tested whether high exposure to advertising affects the memory and guessing processes underlying source attributions. Participants were exposed to high or low proportions of advertising messages that were intermixed with product statements from a trustworthy source. In a subsequent memory test, participants had to remember the sources of these statements. In Experiments 1 and 2, high advertising exposure led to increased source memory and decreased recognition of the statements in comparison to low advertising exposure. High advertising exposure also induced an increased tendency toward guessing that statements whose sources were not remembered came from advertising. The results of Experiment 3 suggest that the presence of advertising, relative to its absence, leads to a skeptical guessing bias. Being exposed to advertising thus has pronounced effects on the memory and guessing processes underlying source attributions. These changes in source monitoring can be interpreted as coping mechanisms that serve to protect against the persuasive influence of advertising messages.

The effects of alcohol and co-witness information on memory reports: a field study.

RATIONALE: Witnesses who discuss a crime together may report details that they did not see themselves but heard about from their co-witness. Co-witness information may have beneficial and harmful effects on memory accuracy depending on whether the information was correct or incorrect. OBJECTIVES: Given the prevalence of intoxicated witnesses, it is imperative to understand how alcohol influences this effect. METHODS: The present study asked pubgoers (n = 67) at varying levels of intoxication to recall a mock crime video after having also watched a video witness statement containing both correct and false information. RESULTS: Increased intoxication was associated with decreased confidence, completeness and accuracy, but no increased tendency to report false information. Exposure to incorrect post-event information (PEI) can lead to the incorporation of incorrect information, whereas exposure to correct PEI increased accuracy, regardless of individuals' alcohol intoxication status. CONCLUSIONS: Thus, whilst discussion and intoxication can negatively impact eyewitness memory, discussion may also have benefits for both sober and intoxicated witnesses.

Passive Light Source Monitoring for Sending or Not Sending Twin-Field Quantum Key Distribution.

Twin-field quantum key distribution (TF-QKD) can break the repeaterless linear bound and possess the measurement-device-independent security, and thus seems very promising in practical applications of quantum secure communication. In most reported TF-QKD protocols, light sources are assumed to possess trusted and fixed photon number distributions (PND), which are unrealistic assumptions in practical applications. Fortunately, the light source monitoring (LSM) method is proposed to circumvent this problem by actively adjusting the attenuation coefficient and monitoring the photon number distribution of light sources. However, the active light source monitoring (ALSM) method may induce additional modulation errors due to imperfect attenuation devices, deteriorating practical performances of TF-QKD systems. In this manuscript, we propose a passive light source monitoring (PLSM) scheme for TF-QKD, and employ the sending-or-not-sending (SNS) TF-QKD as an example for illustration. Simulation results show that our present work can greatly exceed both the original SNS protocol and the ALSM scheme when light source fluctuations and modulation errors are taken into account.

Understanding source monitoring subtypes and their relation to psychosis: a systematic review and meta-analysis.

AIMS: Source monitoring (SM) is the metacognitive ability to determine the origin of one's experiences. SM is altered in primary psychiatric psychosis, although relationships between SM subtypes, other cognitive domains and symptoms are unclear. Our aims were to synthesize evidence comparing psychosis -with and without hallucinations- and healthy controls classifying SM subtypes by source discrimination (internal/external/reality monitoring) and stimulus modality (visual/auditory/imagined/performed). METHODS: This systematic review adopted Preferred Reporting Items for Systematic Reviews and Meta-Analyses, Meta-analyses Of Observational Studies in Epidemiology and Population, Intervention, Comparison and Outcomes guidelines. Core demographical and clinical parameters were extracted. Newcastle-Ottawa Scale was used as quality check. SM differences between (i) psychosis patients versus healthy controls and (ii) patients with versus without hallucinations were investigated via random-effect model meta-analysis. The primary effect size measure was standardized mean difference (SMD) in each SM subtype performance (error or accuracy). Heterogeneity, publication biases and meta-regressions were assessed. RESULTS: Five thousand two hundred and fifty-six records were screened to finally include 44 studies (1566 patients, 1175 controls). Mean Newcastle-Ottawa score was 7.41 out of 9. Few studies measured SM associations with cognition (n = 9) and symptoms (n = 19), with heterogeneous findings. SM performance across all measures was reduced in psychosis versus healthy controls (SMD = 0.458). Internal SM (SMD: errors = 0.513; accuracy = 0.733) and imagined stimuli (SMD: errors = 0.688; accuracy = 0.978) were specifically impaired. Patients with versus without hallucinations showed SM deficits only for externalizing (SMD = 0.410) and imagined/auditory (SMD = 0.498/0.277) errors. CONCLUSION: The proposed classifications highlight specific SM deficits for internal/imagined stimuli in psychosis, providing evidence-based indications to design and interpret future studies.

Individual Differences in Disqualifying Monitoring Underlie False Recognition of Associative and Conjunction Lures.

The current study leveraged experimental and individual differences methodology to examine whether false memories across different list-learning tasks arise from a common cause. Participants completed multiple false memory (associative and conjunction lure), working memory (operation and reading span), and source monitoring (verbal and picture) tasks. Memory discriminability in the associative and conjunction tasks loaded onto a single (general) factor and were unaffected by warnings provided at encoding. Consistent with previous research, source-monitoring ability fully mediated the relation between working memory and false memories. Moreover, individuals with higher source monitoring-ability were better able to recall contextual information from encoding to correctly reject lures. These results suggest that there are stable individual differences in false remembering across tasks. The commonality across tasks may be due, at least in part, to the ability to effectively use disqualifying monitoring processes.

Repeated recall on source misattribution in Alzheimer's disease.

We assessed the effect of repeated recall on item memory and source monitoring in Alzheimer's disease (AD). AD patients and controls were instructed to either look at or imagine items. They then had to either retrieve the items without indicating their source in three consecutive free recall tests, or to remember the source of the retrieved items in three consecutive source tests. Results showed a significant increase in item memory across all three free recall tests and all three source monitoring tests in control participants, but not in AD patients. More source misattributions were observed in AD patients and controls in the third source test than in the first and second tests. The absence of beneficial effect of repeated recall on item memory in AD patients may be attributed to compromise in memory consolidation processes, while the increase in source misattributions due to repetitions may be attributed to the inflation effect.