Source Memory Research Articles

Repetitive transcranial magnetic stimulation (rTMS) as a tool for cognitive enhancement in healthy adults: a review study.

As human beings, we have always sought to expand on our abilities, including our cognitive and motor skills. One of the still-underrated tools employed to this end is repetitive transcranial magnetic stimulation (rTMS). Until recently, rTMS was almost exclusively used in studies with rehabilitation purposes. Only a small strand of literature has focused on the application of rTMS on healthy people with the aim of enhancing cognitive abilities such as decision-making, working memory, attention, source memory, cognitive control, learning, computational speed, risk-taking, and impulsive behaviors. It, therefore, seems that the findings in this particular field are the indirect results of rehabilitation research. In this review paper, we have set to investigate such studies and evaluate the rTMS effectuality in terms of how it improves the cognitive skills in healthy subjects. Furthermore, since the most common brain site used for rTMS protocols is the dorsolateral prefrontal cortex (DLPFC), we have added theta burst stimulation (TBS) wave patterns that are similar to brain patterns to increase the effectiveness of this method. The results of this study can help people who have high-risk jobs including firefighters, surgeons, and military officers with their job performance.

Me and my mom: Self and mother provide similar memory benefits for source memory in adolescents

The self-reference effect (SRE) is a memory benefit found in both adolescents and adults that occurs when new information is connected to the self, facilitating improved recall and recognition. The memory benefit extends to close others, with adults better remembering information encoded in reference to close others as compared to information encoded in connection to an unfamiliar other or neutral control condition, but this has not yet been shown in younger adolescents. The present study examined the role of self and close other in source memory in 41 adolescents (10–14 years old) and 44 young adults (18–25 years old). Findings showed that participants had significantly better memory for information connected to the self and close other compared to other referent conditions and that patterns of memory across conditions are similar in both young adults and adolescents. These findings add to our understanding of the use of self and other referencing in memory in adolescents.

Are multiple types of associative memory differently impacted by emotion?

ABSTRACT The effect of emotion on associative memory is still an open question. Our aim was to test whether discrepant findings are due to differential impact of emotion on different types of associative memory or to differences in the way participants encoded stimuli across studies. We examined the effect of negative content on multiple forms of associative memory, using the same encoding task. Two registered experiments were conducted in parallel with random allocation of participants to experiments. Each experiment included 4 encoding blocks, in which participants read a neutral text comprised of 6 paragraphs, which were interleaved with neutral or negative images. Images were controlled for visual properties and semantic similarity. Memory tests included recognition memory, Remember/Know, order memory, temporal source memory and contextual memory. Analyses showed that emotion decreased contextual memory but not order memory or temporal source memory. We also found that temporal source memory and contextual memory were correlated. Recognition accuracy and subjective recollection were not impacted by emotion. In agreement with previous work, participants self-reported a reduced ability to integrate blocks containing negative images with paragraphs. In contrast to our hypothesis, results suggest that emotion does not impact all types of associative memory when stimuli are controlled.

When does intent matter for memory? Bridging perspectives with Craik.

In his commentary, Craik (see record 2023-42323-002) argued that while intentional remembering might be effective for some populations and memory tasks, these are the exception, and that intent will not benefit memory if incidental encoding induces optimal processing. While we agree on many points, we maintain that in most situations the processes induced by the intention to remember are more effective than those induced by deep semantic processing alone. We show that effects of intent appear with a variety of tasks such as free recall, cued recall, source memory, item recognition, in both mixed and pure lists, and when studying individual words, word pairs, or word-image associations. Thus, the beneficial effects of intent generalize over tasks, list-compositions, and study materials. There are also little individual differences in the effect of intent in healthy young adults-most participants (86% out of 336 participants over six experiments) show a beneficial effect. We review evidence that the intent to remember strengthens item-context bindings in episodic memory, but that such effects could be masked and not measurable in subsequent memory tests, unless intrusions are taken into account. We agree that in principle incidental encoding could induce optimal processing, but we do not find the existing evidence convincing. We provide additional novel data that directly addresses Craik's (2023) concerns and we propose ways to further investigate how intention enhances memory. We conclude with a joint statement, coauthored by Craik and ourselves, that synthesizes our converging perspectives and current understanding of the impact of intent on memory. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

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

ABSTRACT 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.

Dynamic emotional states shape the episodic structure of memory

Human emotions fluctuate over time. However, it is unclear how these shifting emotional states influence the organization of episodic memory. Here, we examine how emotion dynamics transform experiences into memorable events. Using custom musical pieces and a dynamic emotion-tracking tool to elicit and measure temporal fluctuations in felt valence and arousal, our results demonstrate that memory is organized around emotional states. While listening to music, fluctuations between different emotional valences bias temporal encoding process toward memory integration or separation. Whereas a large absolute or negative shift in valence helps segment memories into episodes, a positive emotional shift binds sequential representations together. Both discrete and dynamic shifts in music-evoked valence and arousal also enhance delayed item and temporal source memory for concurrent neutral items, signaling the beginning of new emotional events. These findings are in line with the idea that the rise and fall of emotions can sculpt unfolding experiences into memories of meaningful events.

A - 28 Serial Evaluations of an Older Adult with Epilepsy and Incidental Findings of Early-Onset Alzheimer's Disease: a Case Study.

Patients with Temporal Lobe Epilepsy (TLE) and Alzheimer's Disease (ad) demonstrate increased β-amyloid and tau deposition, relative to patients with either TLE or ad. Presentation of ad may be atypical and more rapid in patients with both disorders. We present four serial neuropsychological evaluations (NPE) of a 68-year-old, right-handed woman with history of epilepsy (which became treatment refractory), neurosurgical resection, and incidental neuropathological findings of early-onset ad. History included generalized tonic-clonic seizure in adolescence and numerous complex partial seizures, managed for ~20years on valproic acid. At age 63, she reported memory changes. Neurophysiological work-up revealed right frontotemporal seizure foci, and neuroimaging studies revealed amyloid angiopathy. She underwent right anterior temporal lobectomy and amygdalohippocampectomy. Afterwards, seizure control and perceived memory function improved. Post-surgical pathological analysis detected neurofibrillary tangles, neuritic plaques, angiopathy, anoxic changes, and gliosis. Later, she and family described memory decline and behavioral disinhibition. Follow-up CSF analysis identified p-tau/β-amyloid ratio consistent with ad. Presurgical NPE was largely intact. Post-surgical NPE revealed stable/improved executive functioning (EF), visuospatial skills (VS), and memory, with variability in language. Follow-up NPE 10months later identified general stability with some variability (e.g., source memory difficulties). Follow-up NPE 16months after that revealed declines in several domains, with sparing of VS and language. We present the cognitive trajectory of an individual with refractory TLE and early-onset ad, complicated by cognitive/neuropsychiatric sequelae of neurosurgical resection. This case highlights the potential benefits of serial re-evaluation in assessing for cognitive change suggestive of ad in aging populations with refractory TLE.

H - 29 Delivering Culturally Sensitive Neuropsychological Assessment Feedback: a Case Study of Atypical Neurosyphilis.

To demonstrate the neuropsychological correlates of atypical neurosyphilis and the importance of delivering assessment results in a culturally sensitive manner. The patient was a 52-year-old African American male with 12years of education who was raised in a rural, southern town and worked as a delivery driver. He was hospitalized after three weeks of altered mental status, memory loss, and seizures. Electroencephalography (EEG) showed left lateralized periodic discharges. Magnetic resonance imaging (MRI) showed hyperintensities in the left hippocampus and amygdala consistent with limbic encephalitis. Cerebrospinal fluid studies revealed lymphocytic pleocytosis and hypoglycorrhachia. Rapid plasma regain and venereal disease tests were positive for syphilis in serum and CSF. He was initially treated with empiric antibiotics and antiseizures medications with modest improvement. His mental status improved after penicillin treatment, and he was discharged after 14days. Repeat MRI showed cortical atrophy in the left medial frontal lobe and left hippocampus. The patient demonstrated executive dysfunction (e.g., set-loss and source memory errors) and poor performance across verbal and visual memory tasks. He also demonstrated an inaccurate understanding of the possible causes of his illness. Feedback was delivered across two sessions: one session to discuss test results and a second session with the patient and his wife to discuss syphilis as a sexually transmitted infection and address the historical context of syphilis among African American men. Neurosyphilis can present as limbic encephalitis and can mimic autoimmune encephalitis and other infectious diseases. Tailoring assessment feedback to a patient's sociocultural context is vital for encouraging continued treatment.

Cephalopod learning and memory

Cephalopod molluscs are renowned for their unique central nervous system - a donut-shaped brain organised around the oesophagus. This brain supports sophisticated learning and memory abilities. Between the 1950s and 1980s, these cognitive abilities were extensively studied in octopus (Figure 1A) - a now leading model for the study of memory and its neural substrates (approximately 200 papers during this period). The focus on octopus learning and memory was mainly due to their curious nature and the fact that they adapt to laboratory-controlled conditions, making them easy to test and maintain in captivity. Research on cephalopod cognition began to widen in the late 20th century, when scientists started focusing on other coleoid cephalopods (i.e., cuttlefish and squid) (Figure 1B,C), and not just on associative learning and memory per se, but other more complex aspects of cognition such as episodic-like memory (the ability to remember the what, where, and when of a past event), source memory (the retrieval of contextual details from a memory), and self-control (the ability to inhibit an action in the present to gain a more valuable future reward). Attention broadened further over the last two decades to focus on the shelled cephalopods - the nautiloids (Figure 1D). The nautiloids have relatively primitive brains compared to their soft-bodied cousins (octopus, cuttlefish, and squid) but research shows that they are still able to comparatively succeed in some cognitive tasks. In this primer, we will provide a general description of the types of memory studied in cephalopods, and discuss learning and memory experiments that address the main challenges cephalopods face during their daily lives: navigation, timing, and food selection. Determining the type of information cephalopods learn and remember and whether they use such information to overcome ecological challenges will highlight why these invertebrates evolved large and sophisticated brains.

Not so different after all? An event-related potential study on item and source memory for object-scene pairs in German and Chinese young adults.

In recent years, several cross-cultural studies reported that Westerners focus more on central aspects of a scene (e.g., an object) relative to peripheral aspects (e.g., the background), whereas Easterners more evenly allocate attention to central and peripheral aspects. In memory tasks, Easterners exhibit worse recognition for the central object when peripheral aspects are changed, whereas Westerners are less affected by peripheral changes. However, most of these studies rely on hit rates without correcting for response bias, whereas studies accounting for response bias failed to replicate cultural differences in memory tasks. In this event-related potential (ERP) study, we investigated item and source memory for semantically unrelated object-scene pairs in German and Chinese young adults using memory measures corrected for response bias (i.e., the discrimination index Pr). Both groups completed study-test cycles with either item memory tests or source memory tests. In item memory blocks, participants completed an old/new recognition test for the central object. Source memory blocks entailed an associative recognition test for the association between object and background. Item and source memory were better for intact than for recombined pairs. However, as verified with frequentist and Bayesian analyzes, this context effect was not modulated by culture. The ERP results revealed an old/new effect for the item memory task in both groups which was again not modulated by culture. Our findings suggest that cultural differences in young adults do not manifest in intentional memory tasks probing memory for object-scene pairs without semantic relations when using bias-corrected memory measures.

You won't believe it! Truth judgments for clickbait headlines benefit (but less so) from prior exposure

AbstractIn two high‐powered experiments, we investigated how prior exposure to statements presented in a clickbait format increases the perceived truth of their content. In Experiment 1 (N = 241), we hypothesized and found that prior exposure increased the proportion of “true” judgments for both non‐clickbait and clickbait content, but with a reduced effect of prior exposure for statements originally presented in a clickbait format. In Experiment 2 (N = 291), turning to continuous ratings, we found higher truth ratings for repeated than new clickbait statements, even when repetition evidently originated from prior exposure to clickbait statements. The present findings suggest that exposure to clickbait headlines can increase their content's truth judgments despite their overall lack of credibility, although to a lesser extent than for more regular statements. The present research additionally supports an implausibility account rather than a source memory account of the truth effect with clickbait statements.

Differentiating the DF effect in episodic memory: evaluating the contribution of the procedures of collaborative memory

Existing research has demonstrated a significant directed forgetting (DF) effect in memory. However, it remains unclear whether this phenomenon would occur in the context of interpersonal collaboration. Additionally, the contribution of emotional valence to the DF effect in item memory and source memory (which are subtypes of episodic memory) also needs to be explored. To address these issues, we conducted two experiments that combined the collaborative memory paradigm with the item-method procedure of DF. In both experiments, positive, neutral, or negative words were presented as stimuli, each followed by an R/F cue during encoding. We conducted two recalls, labeled Recall 1 and Recall 2, which consisted of both memory tasks. Recall 1 was performed either individually or collaboratively, whereas Recall 2 was done individually. Experiment 1 and Experiment 2 adopted the free-flowing procedure and the turn-taking procedure of collaborative memory, respectively. We obtained three implications from our current findings. (a) The occurrence of the DF effect in item memory was found regardless of the procedure of collaborative memory, and it was insensitive to the emotional valence of words or to whether participants had collaborated or not. These patterns demonstrate that both the mechanisms of elaborative rehearsal and active suppression/encoding blocking were engaged across words of different emotional valences and in nominal and collaborative circumstances. (b) In source memory, the DF effect showed different patterns in ongoing and post-collaborative memory, which underpins the dual-process models. (c) The amplitude of the DF effect was sensitive to the interaction of emotional valence by the status of collaboration, and the impact of collaboration differed between the two experiments, offering telling evidence of different aspects of the retrieval strategy disruption hypothesis (RSDH). Directions for identifying more influential factors are put forward.

Examining the effects of emotional valence and arousal on source memory: A meta-analysis of behavioral evidence.

The current meta-analysis examined the effects of valence and arousal on source memory accuracy, including the identification of variables that moderate the magnitude and direction of those effects. Fifty-three studies, comprising 85 individual experiments (N = 3,040 participants), were selected. Three separate analyses focusing on valence effects (valence-based: negative-neutral; positive-neutral; negative-positive) and other three focusing exclusively on arousal (arousal-based: high-low; medium-low; high-medium) were considered. Effect sizes varied from very small to medium. For the valence-based analyses, source memory accuracy was impaired for emotional compared with neutral stimuli (dunb = -.14 for negative-neutral; dunb = -.11 for positive-neutral), with a similar performance found for the negative-positive comparison (dunb = -.04). In the case of arousal-based analyses, source memory was improved for stimuli with high and medium arousal versus low arousal (dunb = .27, dunb = .49, respectively), with no statistically significant difference between high and medium arousal stimuli (dunb = -.12). Emotion effects on source memory were modulated by methodological factors. These factors may account for the variety findings typically found in emotion-related source memory research and could be systematically addressed in future studies. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Acoustic features drive event segmentation in speech.

While our perceptual experience seems to unfold continuously over time, episodic memory preserves distinct events for storage and recollection. Previous work shows that stability in encoding context serves to temporally bind individual items into sequential composite events. This phenomenon has been almost exclusively studied using visual and spatial memory paradigms. Here we adapt these paradigms to test the role of speaker regularity for event segmentation of complex auditory information. The results of our auditory paradigm replicate the findings in other sensory modalities-finding greater within-event temporal memory for items within speaker-bound events and greater source memory for items at speaker or event transitions. The task we use significantly extends the ecological validity of past paradigms by allowing participants to encode the stimuli without any suggestions on the part of the experimenter. This unique property of our design reveals that, while memory performance is strongly dependent on self-reported mnemonic strategy, behavioral effects associated with event segmentation are robust to changes in mnemonic strategy. Finally, we consider the effect of serial position on segmentation effects during encoding and present a modeling approach to estimate the independent contribution of event segmentation. These findings provide several lines of evidence suggesting that contextual stability in perceptual features drives segmentation during word listening and supports a modality-independent role for mechanisms involved in event segmentation. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Does Expecting Matter? The Impact of Experimentally Established Expectations on Subsequent Memory Retrieval of Emotional Words.

Previous studies have confirmed that different degrees of expectation, including the bipolarity of the expected and unexpected, as well as an intermediate level (no expectation), can affect memory. However, only a few investigations have manipulated expectation through experimentally established schema, with no consideration of how expectation impacts both item and source memory. Furthermore, stimulus emotionality may also impact memory. Therefore, we conducted a study to investigate the effects of three levels of expectation on item and source memory while considering the impact of stimulus emotionality. The experiment began with a phase dedicated to learning the rules. In the subsequent study phase, negative and neutral words were manipulated as expected, no expectation, and unexpected, based on these rules. This was followed by tasks focused on item and source memory. The study found that there was a "U-shape" relationship between expectation and item memory. Additionally, the study revealed the distinct impacts of expectation on item and source memory. When it came to item memory, both expected and unexpected words were better remembered than those with no expectations. In source memory, expected words showed memory inferiority for expectation-irrelevant source information, but an advantage for expectation-relevant source information. Stimulus emotionality modulated the effect of expectation on both item and source memory. Our findings provide behavioral evidence for the schema-linked interactions between medial prefrontal and medial temporal regions (SLIMM) theory, which proposes that congruent and incongruent events enhance memory through different brain regions. The different patterns between item and source memory also support dual-process models. Moreover, we speculate that processing events with varying levels of emotionality may undermine the impact of expectation, as implied by other neural investigations.

Sensitivity of late ERP old/new effects in source memory to self-referential encoding focus and stimulus emotionality

In episodic memory, the old/new effect, the contrast of the waveforms elicited by the correctly recognized studied items and the correctly rejected novel items, has been broadly concerned. However, the contribution of self-referential encoding to the old/new effect in source memory (i.e., source-SRE), is far from clarification; further, it remains unclear whether the contribution is susceptible to the factor of stimulus emotionality. To address these issues, adopting the event-related potential (ERP) technique, this study applied words of three types of emotional valences (positive, neutral, vs. negative) in the self-focus vs. external-focus encoding tasks. In the course of the test, four ERP old/new effects were identified: (a) the familiarity- and recollection-reflected mid-frontal effect (FN400) and late positive component (LPC) were both independent of source-SRE and stimulus emotionality; (b) the reconstruction-driven late posterior negativity (LPN) exhibited an adverse pattern of source-SRE and was susceptible to the emotional valence by encoding focus; and (c) the right frontal old/new effect (RFE), reflecting post-retrieval process, exhibited a source-SRE in emotional words. These effects provide compelling evidence for the influences of both stimulus valence and encoding focus on SRE in source memory, especially during the late processes. Further directions considering more perspectives are put forward.

Cognitive test performance in chronic cannabis flower users, concentrate users, and non-users

Extremely high-potency cannabis concentrates are becoming increasingly available and popular among consumers. While prior research indicates these products are perceived to have greater detrimental effects relative to cannabis flower, few studies have examined their relative objective effects, and no existing studies have compared the cognitive test performance of sober flower users, concentrate users, and non-users. A total of 198 healthy adults (98 non-users, 46 exclusive flower users, and 54 concentrate users) were administered a battery of tests of memory, psychomotor speed, attention, and executive functioning under sober laboratory-controlled conditions. Significant group differences were detected on tests of verbal free recall and episodic prospective memory, with both the flower users and concentrate users demonstrating significantly worse performance than non-users. Concentrate (but not flower) users performed worse than non-users on a measure of source memory, but contrary to our hypothesis, there were no significant differences between flower and concentrate users on any of the cognitive tests. Results indicate that, under sober conditions, individuals who regularly use concentrates are no more cognitively impacted than those who exclusively use flower. These null findings may reflect the tendency for concentrate users to self-titrate and use significantly lower quantities of concentrates than flower.

Metacognitive differentiation of item memory and source memory in schema-based source monitoring.

Item memory and source memory are different aspects of episodic remembering. To investigate metamemory differences between them, the authors assessed systematic differences between predictions of item memory via Judgments of Learning (JOLs) and source memory via Judgments of Source (JOSs). Schema-based expectations affect JOLs and JOSs differently: Judgments are higher for expected source-item pairs (e.g., "nightstand in the bedroom") than unexpected pairs (e.g., "bed in the bathroom"), but this expectancy effect is stronger on JOSs than JOLs (Schaper et al., 2019b). The current study tested theoretical underpinnings of this difference. Due to semantic priming, JOLs should be influenced by the consistency between an item and any of the schemas activated at study. JOSs, however, should be influenced by the (in)consistency between an item and its actual source. In three experiments, source-item pairs varied in strength of consistency and inconsistency. Participants provided item-wise JOLs and JOSs. Regardless of an items' actual source, JOLs were higher the more consistent an item was with any of the source schemas, but only if that schema was activated by occurring as a source at study. JOLs were also biased by the actual source: JOLs were lower the more inconsistent an item was with its actual source. By contrast, JOSs were primarily influenced by an item's (in)consistency with its actual source (positively for consistency, negatively for inconsistency). Thus, participants metacognitively differentiated item memory and source memory. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Lack of source memory as a potential marker of early assimilation of novel items into current knowledge

In daily life, humans process a plethora of new information that can be either consistent (familiar) or inconsistent (novel) with prior knowledge. Over time, both types of information can integrate into our accumulated knowledge base via distinct pathways. However, the mnemonic processes supporting the integration of information that is inconsistent with prior knowledge remain under-characterized. In the current study, we used functional magnetic resonance imaging (fMRI) to examine the initial assimilation of novel items into the semantic network. Participants saw three repetitions of adjective-noun word pairs that were either consistent or inconsistent with prior knowledge. Twenty-four hours later, they were presented with the same stimuli again while undergoing fMRI scans. Outside the scanner, participants completed a surprise recognition test. We found that when the episodic context associated with initially inconsistent items was irretrievable, the neural signature of these items was indistinguishable from that of consistent items. In contrast, initially inconsistent items with accessible episodic contexts showed neural signatures that differed from those associated with consistent items. We suggest that, at least one day post encoding, items inconsistent with prior knowledge can show early assimilation into the semantic network only when their episodic contexts become inaccessible during retrieval, thus evoking a sense of familiarity.

Loneliness is associated with a greater self-reference effect in episodic memory when compared against a close friend.

Loneliness describes a negative experience associated with perceived social disconnection. Despite the clear links between loneliness and mental and physical health, relatively little is known about how loneliness affects cognition. In this study, we tested the effect of loneliness on cognitive distance between the self and others, using a task in which participants completed a surprise memory task for adjectives implicitly encoded in relation to the self, a close friend or a celebrity. We assessed item memory sensitivity, metacognitive sensitivity, metacognitive efficiency and source memory for positive and negative words. In addition, participants reported their trait loneliness and depression. Results revealed an overall self-referential advantage compared with both friend and celebrity encoded items. Likewise, a friend-referential advantage was identified compared to celebrity-encoded items. Individuals who experienced more loneliness showed a greater self-referential bias in comparison to words encoded in relation to a close friend, and a smaller friend-referential bias in comparison to words encoded in relation to celebrity. These findings suggest that loneliness is reflected in a greater cognitive distance between the self and close friends in relation to memory biases. The results have important implications for understanding the social contextual effects on memory and the cognitive ramifications of loneliness.