Inconsistency effects in source memory and compensatory schema-consistent guessing

Multinomial processing tree (MPT) models are a class of measurement models that account for categorical data by assuming a finite number of underlying cognitive processes. Traditionally, data are aggregated across participants and analyzed under the assumption of independently and identically distributed observations. Hierarchical Bayesian extensions of MPT models explicitly account for participant heterogeneity by assuming that the individual parameters follow a continuous hierarchical distribution. We provide an accessible introduction to hierarchical MPT modeling and present the user-friendly and comprehensive R package TreeBUGS, which implements the two most important hierarchical MPT approaches for participant heterogeneity—the beta-MPT approach (Smith & Batchelder, Journal of Mathematical Psychology 54:167-183, 2010) and the latent-trait MPT approach (Klauer, Psychometrika 75:70-98, 2010). TreeBUGS reads standard MPT model files and obtains Markov-chain Monte Carlo samples that approximate the posterior distribution. The functionality and output are tailored to the specific needs of MPT modelers and provide tests for the homogeneity of items and participants, individual and group parameter estimates, fit statistics, and within- and between-subjects comparisons, as well as goodness-of-fit and summary plots. We also propose and implement novel statistical extensions to include continuous and discrete predictors (as either fixed or random effects) in the latent-trait MPT model.

Multinomial processing tree (MPT) models can provide novel insights into the cognitive processes underlying a wide variety of social cognitive judgments and behaviors. In previous research, MPT models have been used to disentangle the contributions of multiple latent processes to tasks configured to assess moral reasoning, processing fluency, decision-making, implicit biases, and social categorization, among many other topics. However, until recently, MPT models were limited in their application to categorical data. New methodological advances extend traditional MPT estimation methods by incorporating reaction time data, thereby expanding the breadth and depth of questions that can be investigated. This article provides a user-friendly step-by-step tutorial for response-time extended MPT methods with annotated code and data, using the Implicit Association Test as a working example.

Individuals in preclinical and clinical stages of Huntington's disease (HD) demonstrate impairments in olfactory functioning. In addition, HD patients are impaired in source memory for verbal stimuli. A task combining both source and odor memory may be particularly sensitive to early changes in HD. The present study examined source and item memory for olfactory and visual stimuli in 10 individuals with HD, 10 asymptomatic HD gene carriers, 8 nongene carriers who had a parent with HD, and 20 normal controls. During the study phase, a male and a female experimenter (sources) presented odors and objects to the participant in an alternating sequence. To assess item memory, a stimulus from the study phase (target) and a novel stimulus (distractor) were presented, and the participant was asked to choose the target. To assess source memory, the experimenter presented a stimulus and asked whether the male or female experimenter had previously presented the stimulus. Results indicate that source memory for both visual and olfactory stimuli was impaired in HD patients compared to normal controls. In asymptomatic gene carriers, however, source memory for olfactory stimuli, but not visual stimuli, was more impaired than in nongene carriers and normal controls. Furthermore, gene carriers and HD patients showed a similar degree of impairment in source memory for olfactory stimuli. The only significant impairment found in item memory was for olfactory stimuli in HD patients. These results suggest that source memory for olfactory stimuli may be particularly sensitive to neuropathological changes in preclinical stages of HD.

Multinomial processing tree (MPT) modeling has been widely and successfully applied as a statistical methodology for measuring hypothesized latent cognitive processes in selected experimental paradigms. In this article, we address the problem of selecting the best MPT model from a set of scientifically plausible MPT models, given observed data. We introduce a minimum description length (MDL) based model-selection approach that overcomes the limitations of existing methods such as the G(2)-based likelihood ratio test, the Akaike information criterion, and the Bayesian information criterion. To help ease the computational burden of implementing MDL, we provide a computer program in MATLAB that performs MDL-based model selection for any MPT model, with or without inequality constraints. Finally, we discuss applications of the MDL approach to well-studied MPT models with real data sets collected in two different experimental paradigms: source monitoring and pair clustering. The aforementioned MATLAB program may be downloaded from http://pbr.psychonomic-journals.org/content/supplemental.

Findings reported in the memory literature suggest that the emotional components of an encoding episode can be dissociated from nonemotional memory. In particular, it has been found that the previous association with threatening events can be retrieved in aversive conditioning even in the absence of item identification. In the present study, we test whether emotional source memory can be independent of item recognition. Participants saw pictures of snakes paired with threatening and nonthreatening context information (poisonousness or nonpoisonousness). In the source memory test, participants were required to remember whether a snake was associated with poisonousness or nonpoisonousness. A simple extension of a well-established multinomial source monitoring model was used to measure source memory for unrecognized items. By using this model, it was possible to assess directly whether participants were able to associate a previously seen snake with poisonousness or nonpoisonousness even if the snake itself was not recognized as having been presented during the experiment. In 3 experiments, emotional source memory was only found for recognized items. While source memory for recognized items differed between emotional and nonemotional information, source memory for unrecognized items was equally absent for emotional and nonemotional information. We conclude that emotional context information is bound to item representations and cannot be retrieved in the absence of item recognition. (PsycINFO Database Record

Introduction Remembering relationships between items (information) and the contexts (sources) in which they are framed is crucial for everyday functioning. Total sleep deprivation (TSD) impairs this ability, with evidence suggesting that TSD affects source memory even when items are remembered. Source memory deficits imply problems with associative memory, which relies on hippocampal functioning, known to be altered by TSD. Serotonin is highly expressed in the hippocampus, is influenced by TSD, and may be part of a mechanism by which TSD degrades source memory. We investigated the association between 5-HTTLPR, a functional length polymorphism of the human serotonin transporter gene (SLC6A4), and item and source memory during TSD. Methods N=34 healthy adults (ages 27.3±4.9y; 18 female) participated in a 4-day/3-night laboratory TSD study. Participants underwent 38h TSD, preceded and followed by 10h sleep opportunities. At baseline and 24h later during TSD, they completed an item/source memory task. Participants listened to a list of 60 words each presented by a male or female speaker (study phase). They were then tested for recognition of the words (items) out of 60 old and 60 new words presented visually, and were asked to identify the corresponding speakers (sources, male or female). Results The genotype distribution was in Hardy-Weinberg equilibrium (P=0.34), with 35.3% long/long, 41.2% long/short, 23.5% short/short. Mixed-effects ANOVA showed a significant adverse effect of TSD for both item recognition (P< 0.001) and source recognition (P< 0.001), where TSD degraded source memory even when item recognition was accurate. There were no 5-HTTLPR genotype effects on item memory. However, there was a significant main effect for genotype on source memory (P=0.019), and a genotype by TSD interaction (P=0.018). For accurately recognized items, source memory was largely preserved for the short/short genotype but impaired for carriers of the long allele, and especially the long/long genotype. Conclusion 5-HTTLPR genotype predicted source memory deficits from TSD, distinct from item memory deficits unaffected by genotype, which confirms that item and source memory deficits due to TSD are dissociable. Furthermore, TSD’s impact on binding of items and sources in memory may be mediated by hippocampal serotonin. Support (if any) NIH R21CA167691, WSU Anthony Marchionne and Foundry10 Bridge fellowships

Abstract. The investigation of source monitoring (SM) as a special faculty of episodic memory has gained much attention in recent years. However, several measures of source memory have been used in research practice that show empirical and theoretical shortcomings: First, they often confound various cognitive processes like source memory, item memory and response bias, and second, they do not do justice to the multitude of processes involved in SM according to the framework of Johnson, Hashtroudi, and Lindsay (1993) . We therefore review model-based measurement approaches, focusing on multinomial models, and we distinguish between theorizing about source memory and the pragmatics of source memory measurement as two partly separate goals of research. Whereas signal detection models seem to be more adequate theories of the underlying source monitoring process, multinomial models have some pragmatic advantages that nevertheless recommend them as viable measurement tools.

The present study examined the role of enactment in source memory in a cognitively impaired population. As seen in healthy older adults, it was predicted that source memory in people with mild cognitive impairment due to Alzheimer's disease (MCI-AD) would benefit from the self-reference aspect of enactment. Seventeen participants with MCI-AD and 18 controls worked in small groups to pack a picnic basket and suitcase and were later tested for their source memory for each item. For item memory, self-referencing improved corrected recognition scores for both MCI-AD and control participants. The MCI-AD group did not demonstrate the same benefit as controls in correct source memory for self-related items. However, those with MCI-AD were relatively less likely to misattribute new items to the self and more likely to misattribute new items to others when committing errors, compared with controls. The enactment effect and self-referencing did not enhance accurate source memory more than other referencing for patients with MCI-AD. However, people with MCI-AD benefited in item memory and source memory, being less likely to falsely claim new items as their own, indicating some self-reference benefit occurs for people with MCI-AD.

A functional gradient has been proposed across the medial temporal lobes (MTL) such that the anterior MTL is thought to support processing of individual items (e.g., item memory and complex object perception), whereas the posterior MTL is thought to support item-context retrieval (e.g., source memory). Whereas functional imaging studies have provided evidence supporting this anatomical organization, results from structural analyses remain inconclusive. The current study examined the relationship between volume of MTL regions of interest (ROIs), and performance on a source memory task and a fine-grain complex object perception task, in healthy young adults (mean age = 21.5, range = 18-29). Using a semiautomated procedure, we segmented the parahippocampal and perirhinal cortices (PHC, PRC), posteromedial and anterolateral entorhinal cortices (pmERC, alERC), and posterior and anterior hippocampus (postHC, antHC) on high-resolution T2-weighted MRIs. Regional volumes were computed as proportions of intracranial volume, and as posterior-anterior volumetric ratios (PHC:PRC, pmERC:alERC, postHC:antHC). Partial-least squares regressions were applied to predict source and item memory, and perceptual discrimination accuracy, based on ROI and ratio volumes. In our ROI regressions, we found that postHC volume was positively correlated with a latent factor predicting source memory, and PRC and antHC volumes were negatively correlated to this latent factor. In our ratio regressions, we observed an effect relating the posterior-anterior distribution of gray matter across the MTL with source memory. Our results demonstrate differential associations between anterior and posterior MTL and source memory performance. Findings from this study highlight the importance of considering patterns of structure-behavior associations in the neurobiology of episodic memory.

Negative emotion elicited in high school students enhances consolidation of item memory, but not source memory.

Affective states are closely linked to attention to internal aspects of the self (i.e., self-focused attention). We investigated how self-focused attention induced by emotional experiences affects memory for subsequently presented information. Prior to incidental encoding of affectively neutral target words, participants were induced to feel shame or anger through autobiographical recall (vs. no emotion-induction control condition). Memory for words (item memory) and their associated contextual features (source memory) were subsequently assessed. Self-focused attention, measured by the private self-consciousness scale, was highest in the shame condition, followed by the anger and then control conditions. Item memory was significantly impaired in the shame condition compared to both the anger and control conditions, and self-focused attention negatively mediated the effect of emotion condition on memory performance. Source memory did not significantly differ across the emotion conditions, and we discuss possible factors contributing to this null finding. Our findings suggest that emotion-induced self-focused attention may reduce attentional resources available for encoding task-relevant external information.

GENERAL COMMENTARY article Front. Hum. Neurosci., 06 August 2012Sec. Cognitive Neuroscience Volume 6 - 2012 | https://doi.org/10.3389/fnhum.2012.00231

Accurately assessing learning partners’ knowledge profiles improves collaborative learning. Group awareness tools facilitate constructing such social context knowledge during learning and the formation of learning partner models retrievable afterwards. In this experimental study (N = 70), we investigated potential schema effects in partner modeling: Participants were first provided with descriptions of two learning partners (expert vs. novice of an area) and with their knowledge profiles consisting of knowledge levels (high vs. low) regarding certain topics of this area. In a memory test, participants had to remember the specific knowledge levels of both partners. Partner modeling was analyzed with multinomial processing tree models, as these models disentangle memory and guessing, which are often confounded when schema effects on memory are examined. High and low knowledge levels were equally well remembered for both partners. However, participants showed metacognitive biases, expecting their memory to be better for high knowledge levels. Additionally, knowledge profile estimations revealed that while novices’ knowledge was estimated accurately, experts’ knowledge was overestimated. We discuss the results and potential benefits of using multinomial processing tree models in the learning sciences for and beyond analyzing schema effects in partner modeling.

Recent basic science data indicate that in healthy individuals, self-referential processing and social cognition rely on common neural substrates. The authors assessed self-referential source memory and social cognition in a large sample of schizophrenia outpatients and healthy comparison subjects in order to compare how these critical processes are associated in the two groups. Ninety-one schizophrenia outpatients and 30 healthy comparison subjects were assessed on measures of basic social cognition and source memory for previously learned word items: self-generated, externally presented, and new words. Partial correlations and multiple regression analysis were used to test the association between social cognition measures and source memory performance and the contributions of source memory and general cognitive abilities to a social cognition composite score. Schizophrenia patients demonstrated significantly lower source memory for self-generated items (self-referential source memory) relative to comparison subjects but showed intact external source memory. In both groups, self-referential source memory and social cognition showed strong correlations. When the effects of general cognitive abilities were controlled for, these correlations were attenuated in the schizophrenia patients. Regression analysis revealed discrepancies between groups in the cognitive functions contributing to social cognition performance. Impaired self-referential source memory represents a unique cognitive deficit in schizophrenia. Moreover, the strong association between self-referential source memory and social cognition seen in healthy subjects is reduced in schizophrenia and is moderated by general cognitive abilities. Impairments in the neurocognitive system that underlies both self-referential and social cognition provide a parsimonious explanation for the disturbances in the sense of self and other that characterize schizophrenia.

Females’ superiority in item memory, but not source memory for neutral and emotional Chinese words