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.

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.

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.

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.

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.

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.

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.

Source memory for advertisements: The role of advertising message credibility

Advertising is seen as an untrustworthy source because of the perceived self-interest of the advertisers in presenting product information in a biased or misleading way. Regulations require advertising messages in print and online media to be labeled as advertisements to allow recipients to take source information into account when judging the credibility of the messages. To date, little is known about how these source tags are remembered. Research within the source-monitoring framework suggests that source attributions are not only based on veridical source memory but are often reconstructed through schematic guessing. In two experiments, we examined how the credibility of advertising messages affects these source attribution processes. The source of the messages affected judgments of credibility at the time of encoding, but the source tags were forgotten after a short period of time. Retrospective source attributions in the absence of memory for the source tags were strongly influenced by the a priori credibility of the messages: Statements with a low a priori credibility were more likely to be (mis)attributed to advertising than statements with high a priori credibility. These findings suggest that the mere labeling of untrustworthy sources is of limited use because source information is quickly forgotten and memory-based source attributions are strongly biased by schematic influences.

Deficits in multi-scale top-down processes distorting auditory perception in schizophrenia

Cognitive models postulate that impaired source monitoring incorrectly weights the top-down prediction and bottom-up sensory processes and causes hallucinations. However, the underlying mechanisms of the interaction, such as whether the incorrectly weighting is ubiquitously on all levels of sensory features and whether different top-down processes have distinct effects in subgroups of schizophrenia are still unclear. This study investigates how multi-scale predictions influence perception of basic tonal features in schizophrenia. Sixty-three schizophrenia patients with and without symptoms of auditory verbal hallucinations (AVHs), and thirty healthy controls identified target tones in noise at the end of tone sequences. Predictions of different timescales were manipulated by either an alternating pattern in the preceding tone sequences (long-term regularity) or a repetition between the target tone and the tone immediately before (short-term repetition). The sensitivity index, d prime (d'), was obtained to assess the modulation of predictions on tone identification. Patients with AVHs showed higher d' when the target tones conformed to the long-term regularity of alternating pattern in the preceding tone sequence than when the target tones were inconsistent with the pattern. Whereas, the short-term repetition modulated the tone identification in patients without AVHs. Predictions did not influence tone identification in healthy controls. Our results suggest that impaired source monitoring in schizophrenia patients with AVHs heavily weights top-down predictions over bottom-up perceptual processes to form incorrect perception. The weighting function in source monitoring can extend to the processes of basic tonal features, and predictions at multiple timescales could differentially modulate perception in different clinical populations. The impaired interaction between top-down and bottom-up processes might underlie the development of hallucination symptoms in schizophrenia.

Children's ability to edit their memories when learning about the environment from credible and noncredible websites

One of the many sources of information easily available to children is the internet and the millions of websites providing accurate, and sometimes inaccurate, information. In the current investigation, we examined children’s ability to use credibility information about websites when learning about environmental sustainability. In two studies, children studied two different websites and were tested on what they had learned a week later using a multiple-choice test containing both website items and new distracters. Children were given either no information about the websites or were told that one of the websites (the noncredible website) contained errors and they should not use any information from that website to answer the test. In both studies, children aged 7- to 9-years reported information from the noncredible website even when instructed not to, whereas the 10- to 12-year-olds used the credibility warning to ‘edit out’ information that they had learned from the noncredible website. In Study 2, there was an indication that the older children spontaneously assessed the credibility of the website if credibility markers were made explicit. A plausible explanation is that, although children remembered information from the websites, they needed explicit instruction to bind the website content with the relevant source (the individual websites). The results have implications for children’s learning in an open-access, digital age where information comes from many sources, credible and noncredible. Education in credibility evaluation may enable children to be critical consumers of information thereby resisting misinformation provided through public sources.

Guess what? Different source-guessing strategies for old versus new information

The probability-matching account states that learned specific episodic contingencies of item types and source dominate over general schematic expectations in source guessing. However, recent evidence from Bell et al. [(2020). Source attributions for detected new items: Persistent evidence for schematic guessing. Quarterly Journal of Experimental Psychology, 73(9), 1407-1422] suggest that this only applies to source guessing for information that is recognised as belonging to a previously encoded episode. When information was detected as being new, participants persisted in applying schematic knowledge about the sources' profession. This dissociation in source guessing for detected-old and detected-new information may have been fostered by the specific source-monitoring paradigm by Bell et al. (2020) in which sources were a group of individuals in a certain profession rather than fixed persons from that profession for whom episodic contingencies are more likely to persist also for new information. The aim of the present study was to test whether source guessing for detected-old versus detected-new information also dissociates in a more typical source-monitoring task, the doctor-lawyer paradigm, in which one individual doctor and one lawyer present profession-related information. Despite this change in paradigm, source guessing was based on the item-source contingency only for detected-old information, whereas schematic knowledge persisted for detected-new information. The present study thus adds evidence for persistent schema-based source guessing for new information.

Stealing and sharing memories: Source monitoring biases following collaborative remembering

People experience difficulties tracking the source of their memories following collaborative remembering. This results in a variety of source monitoring errors. Researchers have typically focused on one of these errors - instances of adopting information from external sources as one's own memories. They have failed to investigate the frequency of other possible source monitoring errors. Because of this, it is impossible to say whether observed instances of mistakenly adopting external information represent a true bias in remembering or whether these errors simply reflect one of many memory errors that have an equal likelihood of occurring. In two studies, we teased apart these two possibilities. Members of dyads individually studied pictures with some items appearing in both participants' pictures and some unique to each one's pictures. Participants then collaboratively recalled what items were present. After the collaborative recall, participants completed individual source monitoring tests. We found that participants displayed biases in their source monitoring errors for information discussed during collaborative remembering. They were more likely to adopt information from partners as their own memories than attribute their contributions to their partners. They also more often believed their memories (rather than their partner's) were shared, representing a false consensus. Importantly, these biases only occurred following collaborative remembering and not when individuals received comparable information in a non-social setting. These results illuminate the importance of investigating the relative, and not just absolute, frequency of source monitoring errors and provide insight into how collaborative remembering changes individual memories over time.

The production of false recognition and the associated state of consciousness following encoding in a naturalistic context in aging

Using virtual reality, we implemented a naturalistic variant of the DRM paradigm in young and older adults to evaluate false recall and false recognition. We distinguished false recognition related to the highest semantic association (the critical lures), semantic similarity (i.e. items that belong to the same semantic category), and perceptual similarity (i.e. items that are similar, but not identical in terms of shape or color). The data revealed that younger adults recalled and recognized more correct elements than older adults did while the older adults intruded more critical items than younger adults. Both age groups produced false recognition related to the critical items, followed by perceptually and then semantically related items. False recognitions were highly recollective as they were mainly associated with a sense of remembering, even more so in older adults than in young adults. The decline of executive functions and working memory predicted age-related increases in false memories.

Distinguishing schizophrenia spectrum from non-spectrum disorders among young patients with first episode psychosis and at high clinical risk: The role of basic self-disturbance and neurocognition

INTRODUCTION

The distinction between the schizophrenia spectrum and other types of disorders may be clinically relevant in terms of its predictive validity as suggested by studies showing schizophrenia spectrum patients have more unfavourable outcomes compared to other psychotic disorders. The present study aimed to investigate whether basic self-disturbances and neurocognitive processes that have been linked to psychosis risk have discriminative power for schizophrenia spectrum disorders in patients presenting with first episode psychosis (FEP) and at ultra-high risk for psychosis (UHR).

METHODS

38 FEP patients, 48 UHR patients, and 33 healthy controls were assessed for basic self-disturbances (using the Examination of Anomalous Self-Experience, EASE, interview), source monitoring and aberrant salience (behavioural tasks to measure neurocognitive constructs). Clinical groups were divided into patients with schizophrenia spectrum disorders and those with other non-spectrum disorders and were further compared on measures controlling for symptom severity and age.

RESULTS

Basic self-disturbances distinguished schizophrenia spectrum from non-spectrum disorders in the 'FEP only' sample, F = 19.76, p < 0.001, η²_partial = 0.37, and also in the combined UHR/FEP sample, F = 23.56, p < 0.001, η²_partial = 0.22. Additionally, some processes related to source monitoring deficits were elevated in schizophrenia spectrum disorders. In contrast, the two groups (schizophrenia spectrum vs other diagnoses) performed similarly in aberrant salience tasks. Comparable results were obtained for analyses performed with an FEP/UHR combined sample and the 'FEP only' sample.

DISCUSSION

Basic self-disturbances at the phenomenological level and source monitoring deficits on the neurocognitive level may be useful in identifying risk of schizophrenia spectrum disorders at the earliest clinical presentation.

The metamemory expectancy illusion in source monitoring affects metamemory control and memory

In source monitoring, schematic expectations affect both memory and metamemory. In metamemory judgments, people predict better source memory for items that originated from an expected source (e.g., oven in the kitchen) than for items that originated from an unexpected source (e.g., hairdryer in the kitchen; expectancy effect; Schaper et al., 2019a). By contrast, actual source memory is either unaffected by expectations or better for unexpected sources (inconsistency effect; Kuhlmann & Bayen, 2016). Thus, the metamemory expectancy effect is illusory. This research is the first to test the hypotheses that such metamemory monitoring of source memory affects metamemory control (i.e., measures taken to achieve a desired level of memory; Nelson & Narens, 1990) and memory. Due to their expectancy illusion, people should choose to restudy unexpected source-item pairs more often. Three participant groups (n = 36 each) studied expected and unexpected source-item pairs. One group rendered metamemory judgments and chose pairs for restudy. A second group made restudy choices only. These two groups then restudied the chosen pairs. A third group did not make restudy choices and restudied a random half of the pairs. All participants completed a source-monitoring test. As predicted, participants chose unexpected pairs more often for restudy based on their illusory conviction that they would remember unexpected sources more poorly. These restudy choices concurred with an inconsistency effect on source memory not shown in the group without restudy choices. Thus, the metamemory illusion related to control and memory in source monitoring.

Developmental trends in children's source and destination memory

Destination memory (the ability to remember who one has told information to) has been studied in adult samples, but not with child participants. The goals of the current research were to describe the development of children's destination memory abilities across early to middle childhood and to compare destination memory with source-monitoring abilities within the same age range. In two studies, children aged 5-10 years had conversations with two puppets and were later asked to recall which puppet they had disclosed specific information to. Study 1 (N = 86) revealed age to be a significant predictor of destination memory accuracy. Study 2 (N = 90) demonstrated that source memory and destination memory were related and shared a similar developmental trajectory but that source accuracy was higher on average than destination accuracy. This research contributes to our theoretical understanding of children's memory development, and directions for future research are highlighted in the Discussion. Implications for investigative interviews in which children are asked about prior disclosures are discussed.

The role of goals and outcomes in young children's memory for actions

Four- to six-year-old children participated in three experiments designed to investigate action features that may contribute to the self-enactment effect and help clarify contradictory findings in the literature. Although activity is important in young children's learning and development, preschoolers' memory for self-actions is often found to be no better than memory for another person's actions. In the few studies in which the self-enactment effect has been found for this age group, the actions included as test materials differ markedly from those in the studies in which no differences occur. Specifically, the actions in studies finding the effect are goal-directed and enable outcomes whereas the actions in studies that don't find the effect have no instrumental goals, other than to perform the action, and often do not enable outcomes external to the action carried out. In Experiment 1 source memory and in Experiment 2 free recall were better for children's own actions than those of the experimenter when children participated in actions that produced outcomes in a game-like context. Findings from these two studies suggested that action outcomes were particularly important in these self-enactment effects which were then verified in Experiment 3. Our results support the role of self-directed actions for learning in early childhood classrooms, but highlight the contribution of goal-based activities that lead to instrumental and enabling outcomes in that learning.

Self-Monitoring for speech and its links to age, cognitive effort, schizotypal trait expression and impulsivity during adolescence

Introduction: Disruptions in self-monitoring processes represent key cognitive factors associated with schizophrenia spectrum disorders. In the current study, we assessed the effects of age and cognitive effort on self-monitoring for speech in adolescence, as well as its associations with personality dimensions pertaining to schizotypy and impulsivity.Methods: 121 community adolescents undertook a self-monitoring task that assesses the capacity to discriminate between self-generated overt and silent speech, for items requiring different levels of cognitive effort. Self-report measures were used to assess trait dimensions of schizotypy and impulsivity.Results: Cognitive effort, but not age, contributed to the overall rate of self-monitoring errors. Contrary to clinical psychosis and high risk samples, increased cognitive effort in healthy adolescents led to more internalising than externalising self-monitoring errors. Higher scores on the interpersonal dimension of schizotypy were associated with increases in the total rate of self-monitoring errors. No associations were found between positive schizotypy and externalising self-monitoring misattributions. Finally, trait impulsivity dimensions were not associated with self-monitoring performance.Conclusions: The present findings suggest that self-monitoring confusions may be linked to trait-risk for psychosis in adolescence. Future studies can prospectively assess whether the association between negative schizotypal traits and self-monitoring represents a distal marker of psychosis vulnerability.

Source attributions for detected new items: Persistent evidence for schematic guessing

Performance in source-monitoring tests is not only determined by source memory but also by source guessing. Source guessing is not random as it is informed by two distinct mechanisms. (1) People may show a schema-based guessing bias and rely on cross-situationally stable world knowledge. (2) They may apply probability matching and rely on the specific item-source contingency experienced at encoding. According to probability matching theory, source guessing is based on probability matching when a specific contingency representation is available. This conclusion is derived from a source-monitoring paradigm in which no source judgements for detected new items are required. Here, we extend this paradigm to examine source guessing not only for detected old items but also for detected new items. The results suggest that participants take the old-new recognition status of the items into account when making source attributions. Probability matching is used only for detected old items: Source guessing sensitively reflects the item-source contingency for these items. For detected new items, participants resort to schema-based guessing. Using schema-based guessing rather than probability matching when judging detected new items may have the advantage that a newly acquired contingency representation that may only be locally valid is not generalised too readily at the expense of a schematic expectation that reflects a larger and more comprehensive learning history.

Is it all in the details? Description content and false recognition errors

In three experiments, we examined the effect of embellished content on memory errors for thematically related items as well as whether an encoding manipulation, specifically instructions to visualize content, further affects those errors. Using a modified Deese-Roediger-McDermott (DRM) paradigm, participants listened to subsets of DRM items embedded within scene descriptions. Some descriptions embellished item connections, weaving them into cohesive scenes. Other descriptions only made general reference to scenes, mentioning the items in list-like format. Listening to more detailed descriptions, compared to general scene references, elicited higher false recognition errors (Experiments 1 and 3). However, when description details varied within the same encoding series, as expected, false recognition errors did not differ significantly (Experiments 2 and 3). Results further suggest that more detailed content was more vividly imagined, providing one possible mechanism for increases in false recognition (Experiment 3). Implications for theoretical discussions of encoding task effects on false recognition errors are discussed.

Brief Report: Memory for Self-Performed Actions in Adults with Autism Spectrum Disorder: Why Does Memory of Self Decline in ASD?

The decline in self-related memory in ASD was investigated by using encoding, forgetting, and source monitoring. Participants memorized action sentences verbally, observationally, or by enacted encoding. Then, they underwent recall, recognition, and source monitoring memory tests immediately and 1 week later. If the information were properly encoded, memory performance in the enacted encoding would be the highest (enactment effect). The result of memory tests in ASD and TD people showed that enacted encoding was superior. However, recall and source monitoring in ASD was significantly lower than in TD, which was not the case for recognition and forgetting. These results suggest that the decline in memory of self in ASD is associated with a deficit in memory reconstruction and source monitoring.

Intentional inhibition but not source memory is related to hallucination-proneness and intrusive thoughts in a university sample

Proneness to unusual perceptual states - such as auditory or visual hallucinations - has been proposed to exist on a continuum in the general population, but whether there is a cognitive basis for such a continuum remains unclear. Intentional cognitive inhibition (the ability to wilfully control thoughts and memories) is one mechanism that has been linked to auditory hallucination susceptibility, but most evidence to date has been drawn from clinical samples only. Moreover, such a link has yet to be demonstrated over and above relations to other cognitive skills (source monitoring) and cognitive states (intrusive thoughts) that often correlate with both inhibition and hallucinations. The present study deployed two tests of intentional inhibition ability - the Inhibition of Currently Irrelevant Memories (ICIM) task and Directed Forgetting (DF) task - and one test of source monitoring (a source memory task) to examine how cognitive task performance relates to self-reported i) auditory hallucination-proneness and ii) susceptibility to intrusive thoughts in a non-clinical student sample (N = 76). Hierarchical regression analyses were used to assess the independent and combined contributions of task performance to proneness scores. ICIM performance but not DF or source memory scores were significantly related to both hallucination-proneness and intrusive thoughts. Further analysis suggested that intrusive thoughts may mediate the link between intentional inhibition skills and auditory hallucination-proneness, suggesting a potential pathway from inhibition to perception via intrusions in cognition. The implications for studying cognitive mechanisms of hallucination and their role in "continuum" views of psychosis-like experiences are discussed.

Relations Between Language and Cognition: Evidentiality and Sources of Knowledge

Understanding and acquiring language involve mapping language onto conceptual representations. Nevertheless, several issues remain unresolved with respect to (a) how such mappings are performed, and (b) whether conceptual representations are susceptible to cross-linguistic influences. In this article, we discuss these issues focusing on the domain of evidentiality and sources of knowledge. Empirical evidence in this domain yields growing support for the proposal that linguistic categories of evidentiality are tightly linked to, build on, and reflect conceptual representations of sources of knowledge that are shared across speakers of different languages.

Lower P300 amplitudes for internally-generated events in patients with schizophrenia

BACKGROUND

Patients with schizophrenia demonstrate difficulty differentiating internally-generated from externally-generated events. An excessive deployment of attention to external events as well as poor processing of self-generated events has been proposed to explain this misattribution. This study was done to understand the neurophysiological basis of source monitoring bias in schizophrenia.

METHODS

Seventeen patients and fourteen healthy controls completed a two-stage source monitoring task involving solving a three-letter jumbled word either by the participant or a computer following which they had to identify the correct source of the word - solved by self (internal source monitoring, ISM) or by computer (external source monitoring, ESM) - while EEG was recorded. P300 amplitude and latency were computed separately for ISM and ESM conditions.

RESULTS

P300 amplitude for ISM condition was lower in patients with schizophrenia compared to controls over right and left parietal regions. Additionally, P300 amplitude for ISM condition was lower compared to ESM condition in patients over right and left parietal regions. However, P300 amplitude for ESM condition did not differ significantly between the groups. In contrast to P300 amplitude, there was no significant difference in P300 latency in ISM or ESM condition within or between the groups.

CONCLUSION

P300 amplitude was lower for internally-generated but not externally-generated events in patients with schizophrenia. These findings suggest that patients allocate less attentional resources to internally generated events resulting in poorer processing and consequent misattribution of their source of origin. This study provides the first specific electrophysiological evidence of impaired source monitoring in schizophrenia.

When and where in aging: the role of music on source monitoring

Difficulties in source monitoring (SM) tasks observed in healthy older adults may be linked to associative memory deficits since SM requires individuals to correctly bind and later remember these bound features to discriminate the origin of a memory. Therefore, focusing attention on discriminating factors that may attenuate older adults' difficulties in attributing contextual information to memories is necessary. We investigated the effect of affective information on source monitoring in younger and older adults by manipulating the type of affective information (pictures and music) and assessing the ability to remember spatial and temporal source details for affective pictures encoded while listening to classical music. Older and younger adults viewed a series of affective IAPS pictures presented on the left or right side of the computer screen in two different lists. At test, participants were asked to remember if the picture was seen (right/left), in which list (list1/list2) or whether it was new. Results showed that spatial information was attributed better than temporal information and emotional pictures were attributed better than neutral pictures in both younger and older adults. In addition, although music significantly increased source memory performance in both younger and older participants compared to the white noise condition, the pleasantness of music differentially affected memory for source details. The authors discuss findings in terms of an interaction between music, emotion and cognition in aging.

Follow (or don't follow) the crowd: Young children's conformity is influenced by norm domain and age

This study investigated whether young children's conformity to a consensus varies across the normative domain and age. A total of 168 3- and 5-year-olds participated. Each child was presented with a puzzle box that had two transparent compartments. In a reward preference condition, one of the compartments contained 1 sticker, whereas the other compartment contained 12 stickers. In perceptual judgment and arbitrary preference conditions, one compartment contained a short plank, whereas one contained a perceptually longer plank. Each child was shown a video of four female adults, each of whom was asked the same question within condition: "Which one's the biggest?" (perceptual task; each model retrieved the smaller block), "Which one do you want?" (reward preference; each model retrieved the smaller reward), and "Which one do you want?" (arbitrary preference; each model retrieved the smaller plank). Children were then asked the same question by condition and were allowed to retrieve the item. Notably, more children conformed in the arbitrary preference condition than in the reward preference and perceptual judgment conditions, with 3-year-olds conforming significantly more than 5-year-olds. The 5-year-olds were more successful and imitated with greater fidelity, including demonstrating overimitation. However, less overimitation was observed in the arbitrary preference condition. Together, these findings show that children are sensitive to the contextual cues of the domain in which they are witnessing norms and vary their own conformity based on such cues. Furthermore, children can navigate which information to copy to fulfil their own ends.

Dissociation of item and source memory in rhesus monkeys

Source memory, or memory for the context in which a memory was formed, is a defining characteristic of human episodic memory and source memory errors are a debilitating symptom of memory dysfunction. Evidence for source memory in nonhuman primates is sparse despite considerable evidence for other types of sophisticated memory and the practical need for good models of episodic memory in nonhuman primates. A previous study showed that rhesus monkeys confused the identity of a monkey they saw with a monkey they heard, but only after an extended memory delay. This suggests that they initially remembered the source - visual or auditory - of the information but forgot the source as time passed. Here, we present a monkey model of source memory that is based on this previous study. In each trial, monkeys studied two images, one that they simply viewed and touched and the other that they classified as a bird, fish, flower, or person. In a subsequent memory test, they were required to select the image from one source but avoid the other. With training, monkeys learned to suppress responding to images from the to-be-avoided source. After longer memory intervals, monkeys continued to show reliable item memory, discriminating studied images from distractors, but made many source memory errors. Monkeys discriminated source based on study method, not study order, providing preliminary evidence that our manipulation of retention interval caused errors due to source forgetting instead of source confusion. Finally, some monkeys learned to select remembered images from either source on cue, showing that they did indeed remember both items and both sources. This paradigm potentially provides a new model to study a critical aspect of episodic memory in nonhuman primates.

Assumptions behind scoring source versus item memory: Effects of age, hippocampal lesions and mild memory problems

Source monitoring paradigms have been used to separate: 1) the probability of recognising an item (Item memory) and 2) the probability of remembering the context in which that item was previously encountered (Source memory), conditional on it being recognised. Multinomial Processing Tree (MPT) models are an effective way to estimate these conditional probabilities. Moreover, MPTs make explicit the assumptions behind different ways to parameterise Item and Source memory. Using data from six independent groups across two different paradigms, we show that one would draw different conclusions about the effects of age, age-related memory problems and hippocampal lesions on Item and Source memory, depending on the use of: 1) standard accuracy calculation vs MPT analysis, and 2) two different MPT models. The MPT results were more consistent than standard accuracy calculations, and furnished additional parameters that can be interpreted in terms of, for example, false recollection or missed encoding. Moreover, a new MPT structure that allowed for separate memory representations (one for item information and one for item-plus-source information; the Source-Item model) fit the data better, and provided a different pattern of significant differences in parameters, than the more conventional MPT structure in which source information is a subset of item information (the Item-Source model). Nonetheless, there is no theory-neutral way of scoring data, and thus proper examination of the assumptions underlying the scoring of source monitoring paradigms is necessary before theoretical conclusions can be drawn.

An exploratory high-density EEG investigation of the misinformation effect: Attentional and recollective differences between true and false perceptual memories

The misinformation effect, a phenomenon in which eyewitness memories are altered via exposure to post-event misinformation, is one of the most important paradigms used to investigate the reconstructive nature of human memory. The aim of this study was to use the misinformation effect paradigm to investigate differences in attentional and recollective processing between true and false event memories. Nineteen participants completed a variant of the misinformation paradigm in which recognition responses to true and misinformation based event details embedded within a narrative context, were investigated using high-density (256-channel) EEG with a 1-day delay between event exposure and test. Source monitoring responses were used to isolate event-related-potentials (ERPs) associated with perceptual (i.e. event) source attributions. Temporal-spatial analyses of these ERPs showed evidence of an elevated P3b and Late-Positive Component, associated with stronger context-matching responses and recollective activity respectively, in true perceptual memories relative to false misinformation based ones. These findings represent the first retrieval focused EEG investigation of the misinformation effect and highlight the interplay between attention and retrieval processes in episodic memory recognition.

Reduced multimodal integration of memory features following continuous theta burst stimulation of angular gyrus

BACKGROUND

Lesions of the angular gyrus (AnG) region of human parietal cortex do not cause amnesia, but appear to be associated with reduction in the ability to consciously experience the reliving of previous events.

OBJECTIVES/HYPOTHESIS

We used continuous theta burst stimulation to test the hypothesis that the cognitive mechanism implicated in this memory deficit might be the integration of retrieved sensory event features into a coherent multimodal memory representation.

METHODS

Healthy volunteers received stimulation to AnG or a vertex control site after studying stimuli that each comprised a visual object embedded in a scene, with the name of the object presented auditorily. Participants were then asked to make memory judgments about the studied stimuli that involved recollection of single event features (visual or auditory), or required integration of event features within the same modality, or across modalities.

RESULTS

Participants' ability to retrieve context features from across multiple modalities was significantly reduced after AnG stimulation compared to stimulation of the vertex. This effect was observed only for the integration of cross-modal context features but not for integration of features within the same modality, and could not be accounted for by task difficulty as performance was matched across integration conditions following vertex stimulation.

CONCLUSION

These results support the hypothesis that AnG is necessary for the multimodal integration of distributed cortical episodic features into a unified conscious representation that enables the experience of remembering.

Memory distrust syndrome, confabulation and false confession

There are three types of false confessions: 'voluntary', 'pressured-compliant' and 'pressured-internalized'. On the basis of case studies, in the early 1980s Gudjonsson and MacKeith coined the term 'memory distrust syndrome (MDS)' to describe a condition where people develop profound distrust of their memory and become susceptible to relying on external cues and suggestions from others. Memory distrust can, under certain circumstances, lead to a false confession, particularly of the pressured-internalized type, described as 'confabulation'. This article reviews the evidence for the condition and the psychological mechanism and processes involved. A heuristic model is then presented of a 32 year old man who falsely confessed to murder whilst in police custody. The key elements of the model involve the impact of 'contextual risk factors' (i.e., isolation, long and persistent guilt presumptive interrogation, and high emotional intensity) on 'enduring' vulnerability and 'acute state' factors. The detainee had kept a detailed diary whilst in solitary confinement that provided a unique insight into the gradual development of a MDS, his mental state, and thinking process. This type of false confession is apparently quite rare, but it can occur in intellectually able and educated individuals and involves 'delayed' rather than 'immediate' suggestibility.

The affective reactivity of psychotic speech: The role of internal source monitoring in explaining increased thought disorder under emotional challenge

Thought disorder (TD) has been shown to vary in relation to negative affect. Here we examine the role internal source monitoring (iSM, i.e. ability to discriminate between inner speech and verbalized speech) in TD and whether changes in iSM performance are implicated in the affective reactivity effect (deterioration of TD when participants are asked to talk about emotionally-laden topics). Eighty patients diagnosed with schizophrenia-spectrum disorder and thirty healthy controls received interviews that promoted personal disclosure (emotionally salient) and interviews on everyday topics (non-salient) on separate days. During the interviews, participants were tested on iSM, self-reported affect and immediate auditory recall. Patients had more TD, poorer ability to discriminate between inner and verbalized speech, poorer immediate auditory recall and reported more negative affect than controls. Both groups displayed more TD and negative affect in salient interviews but only patients showed poorer performance on iSM. Immediate auditory recall did not change significantly across affective conditions. In patients, the relationship between self-reported negative affect and TD was mediated by deterioration in the ability to discriminate between inner speech and speech that was directed to others and socially shared (performance on the iSM) in both interviews. Furthermore, deterioration in patients' performance on iSM across conditions significantly predicted deterioration in TD across the interviews (affective reactivity of speech). Poor iSM is significantly associated with TD. Negative affect, leading to further impaired iSM, leads to increased TD in patients with psychosis. Avenues for future research as well as clinical implications of these findings are discussed.

Does aging affect source monitoring and cognitive confidence in schizophrenia? Preliminary results

This study tested the influence of aging on source-monitoring and cognitive confidence deficits in schizophrenia. Younger (n=13) and older (n=10) schizophrenia patients were compared with younger (n=17) and older (n=10) healthy controls in the source-monitoring task. These preliminary results suggest that age negatively influences old/new item recognition, but not source monitoring, in both groups. Age has a negative impact on subjective confidence, but no interaction between group and age was found.

Dual processes of false recognition in kindergarten children and elementary school pupils

We investigated the contribution of monitoring processes to the emergence of false memories in children. Two age groups were compared, assuming lower monitoring ability at preschool age compared with older children. We also manipulated whether elementary school pupils responded in the memory test with or without time pressure. Furthermore, the frequency of list presentation was manipulated within participants. We found that presenting lists thrice compared with only once increased the number of false memories in kindergarten children and in elementary school pupils responding under time pressure but reduced false memories in elementary school pupils responding without time pressure. These findings indicate that kindergarten children still lack the ability to monitor the source of the activation of critical items of Deese-Roediger-McDermott lists.

Functional brain networks involved in reality monitoring

Source monitoring refers to the recollection of variables that specify the context and conditions in which a memory episode was encoded. This process involves using the qualitative and quantitative features of a memory trace to distinguish its source. One specific class of source monitoring is reality monitoring, which involves distinguishing internally generated from externally generated information, that is, memories of imagined events from real events. The purpose of the present study was to identify functional brain networks that underlie reality monitoring, using an alternative type of source monitoring as a control condition. On the basis of previous studies on self-referential thinking, it was expected that a medial prefrontal cortex (mPFC) based network would be more active during reality monitoring than the control condition, due to the requirement to focus on a comparison of internal (self) and external (other) source information. Two functional brain networks emerged from this analysis, one reflecting increasing task-related activity, and one reflecting decreasing task-related activity. The second network was mPFC based, and was characterized by task-related deactivations in areas resembling the default-mode network; namely, the mPFC, middle temporal gyri, lateral parietal regions, and the precuneus, and these deactivations were diminished during reality monitoring relative to source monitoring, resulting in higher activity during reality monitoring. This result supports previous research suggesting that self-referential thinking involves the mPFC, but extends this to a network-level interpretation of reality monitoring.

Influences of Age and Emotion on Source Guessing: Are Older Adults More Likely to Show Fear-Relevant Illusory Correlations?

OBJECTIVES

The present study investigates age differences in the vulnerability to illusory correlations between fear-relevant stimuli and threatening information.

METHOD

Younger and older adults saw pictures of threatening snakes and nonthreatening fish, paired with threatening and nonthreatening context information ("poisonous" and "nonpoisonous") with a null contingency between animal type and poisonousness. In a source monitoring test, participants were required to remember whether an animal was associated with poisonousness or nonpoisonousness. Illusory correlations were implicitly measured via a multinomial model. One advantage of this approach is that memory and guessing processes can be assessed independently. An illusory correlation would be reflected in a higher probability of guessing that a snake rather than a fish was poisonous if the poisonousness of the animal was not remembered.

RESULTS

Older adults showed evidence of illusory correlations in source guessing while younger adults did not; instead they showed evidence of probability matching. Moreover, snake fear was associated with increased vulnerability to illusory correlations in older adults.

DISCUSSION

The findings confirm that older adults are more susceptible to fear-relevant illusory correlations than younger adults.

Early testimonial learning: monitoring speech acts and speakers

Testimony provides children with a rich source of knowledge about the world and the people in it. However, testimony is not guaranteed to be veridical, and speakers vary greatly in both knowledge and intent. In this chapter, we argue that children encounter two primary types of conflicts when learning from speakers: conflicts of knowledge and conflicts of interest. We review recent research on children's selective trust in testimony and propose two distinct mechanisms supporting early epistemic vigilance in response to the conflicts associated with speakers. The first section of the chapter focuses on the mechanism of coherence checking, which occurs during the process of message comprehension and facilitates children's comparison of information communicated through testimony to their prior knowledge, alerting them to inaccurate, inconsistent, irrational, and implausible messages. The second section focuses on source-monitoring processes. When children lack relevant prior knowledge with which to evaluate testimonial messages, they monitor speakers themselves for evidence of competence and morality, attending to cues such as confidence, consensus, access to information, prosocial and antisocial behavior, and group membership.

Process dissociation of familiarity and recollection in children: response deadline affects recollection but not familiarity

According to dual-process theories, recollection (slow and associated with contextual details) and familiarity (fast and automatic) are two independent processes underlying recognition memory. An adapted version of the process dissociation paradigm was used to measure recognition memory in 5-, 7-, and 11-year-olds and adults. In Experiment 1, it was found that 5-year-olds already recollect details of items (i.e., number). Recollection increased particularly between 5 and 7 years. Familiarity differed between 5 years and adulthood. In Experiment 2, under limited response time during retrieval, recollection was eliminated in 5-year-olds and reduced across all ages, whereas familiarity was left unaffected. Together, these findings are consistent with dual-process theories of recognition memory and provide support for two processes underlying recognition memory from a developmental perspective.

False recognition of instruction-set lures

False remembering has been examined using a variety of procedures, including the Deese-Roediger-McDermott procedure, the false fame procedure and the two-list recognition procedure. We present six experiments in a different empirical framework examining false recognition of words included in the experimental instructions (instruction-set lures). The data show that participants' false alarm rate to instruction-set lures was twice their false alarm rate to standard lures. That result was statistically robust even when (1) the relative strength of targets to instruction-set lures was increased, (2) participants were warned about the instruction-set lures, (3) the instruction-set lures were camouflaged in the study instructions and (4) the instruction-set lures were presented verbally at study but visually at test. False recognition of instruction-set lures was only mitigated when participants were distracted between encountering the instruction-set lures and studying the training list. The results confirm the ease with which recognition succumbs to familiarity and demonstrate the robustness of false recognition.

Confidence-accuracy resolution in the misinformation paradigm is influenced by the availability of source cues

After witnessing an event, people often report having seen details that were merely suggested to them. Evidence is mixed regarding how well participants can use confidence judgments to discriminate between their correct and misled memory reports. We tested the prediction that the confidence-accuracy relationship for misled details depends upon the availability of source cues at retrieval. In Experiment 1, participants (N=77) viewed a videotaped staged crime before reading a misleading narrative. After seven minutes or one week, the participants completed a cued recall test for the details of the original event. Prior to completing the test, all participants were warned that the narrative contained misleading details to encourage source monitoring. The results showed that the strength of the confidence-accuracy relationship declined significantly over the delay. We interpret our results in the source monitoring framework. After an extended delay, fewer diagnostic source details were available to participants, increasing reliance on retrieval fluency as a basis for memory and metamemory decisions. We tested this interpretation in a second experiment, in which participants (N=42) completed a source monitoring test instead of a cued recall test. We observed a large effect of retention interval on source monitoring, and no significant effect on item memory. This research emphasizes the importance of securing eyewitness statements as soon as possible after an event, when witnesses are most able to discriminate between information that was personally seen and information obtained from secondary sources.

Investigating the variability of memory distortion for an analogue trauma

In this paper, we examine whether source monitoring (SM) errors might be one mechanism that accounts for traumatic memory distortion. Participants watched a traumatic film with some critical (crux) and non-critical (non-crux) scenes removed. Twenty-four hours later, they completed a memory test. To increase the likelihood participants would notice the film's gaps, we inserted visual static for the length of each missing scene. We then added manipulations designed to affect people's SM behaviour. To encourage systematic SM, before watching the film, we warned half the participants that we had removed some scenes. To encourage heuristic SM some participants also saw labels describing the missing scenes. Adding static highlighting, the missing scenes did not affect false recognition of those missing scenes. However, a warning decreased, while labels increased, participants' false recognition rates. We conclude that manipulations designed to affect SM behaviour also affect the degree of memory distortion in our paradigm.

Source misattributions and false recognition errors: examining the role of perceptual resemblance and imagery generation processes

In three experiments, we examine the extent to which participants' memory errors are affected by the perceptual features of an encoding series and imagery generation processes. Perceptual features were examined by manipulating the features associated with individual items as well as the relationships among items. An encoding instruction manipulation was included to examine the effects of explicit requests to generate images. In all three experiments, participants falsely claimed to have seen pictures of items presented as words, committing picture misattribution errors. These misattribution errors were exaggerated when the perceptual resemblance between pictures and images was relatively high (Experiment 1) and when explicit requests to generate images were omitted from encoding instructions (Experiments 1 and 2). When perceptual cues made the thematic relationships among items salient, the level and pattern of misattribution errors were also affected (Experiments 2 and 3). Results address alternative views about the nature of internal representations resulting in misattribution errors and refute the idea that these errors reflect only participants' general impressions or beliefs about what was seen.

A model of memory impairment in schizophrenia: cognitive and clinical factors associated with memory efficiency and memory errors

BACKGROUND

Memory impairments in patients with schizophrenia have been associated with various cognitive and clinical factors. Hallucinations have been more specifically associated with errors stemming from source monitoring failure.

METHODS

We conducted a broad investigation of verbal memory and visual memory as well as source memory functioning in a sample of patients with schizophrenia. Various memory measures were tallied, and we studied their associations with processing speed, working memory span, and positive, negative, and depressive symptoms.

RESULTS

Superficial and deep memory processes were differentially associated with processing speed, working memory span, avolition, depression, and attention disorders. Auditory/verbal and visual hallucinations were differentially associated with specific types of source memory error.

CONCLUSIONS

We integrated all the results into a revised version of a previously published model of memory functioning in schizophrenia. The model describes the factors that affect memory efficiency, as well as the cognitive underpinnings of hallucinations within the source monitoring framework.