Memory for faces dissociates from memory for location following anterior temporal lobectomy

It has been suggested that the right and left mesial temporal lobes are specialized for processing different types of information for long-term memory (LTM). Although findings have been consistent in regard to the dominant role of the left mesial temporal lobe (MTL) in verbal memory, the role of the right MTL in non-verbal memory remains debatable. Given the existence of two cortical pathways specialized for processing different types of visuospatial information, we examined whether memory processing for these two types of information might also be differentially localized. The effect of unilateral anterior temporal lobectomy (ATL) was compared for memory for unfamiliar faces and a novel sequence of spatial locations in 86 ATL patients (left ATL (LATL) = 35; right ATL (RATL) = 51) pre- and post-surgery to examine the contributions of right and left MTL structures to LTM for pattern and spatial information. Memory for spatial location was not related to side of ATL or time of testing. On the facial memory task, RATL patients showed impairments relative to LATL patients prior to surgery, which became magnified after surgery. These results extend the proposed dissociation between an occipitotemporal and an occipitoparietal pathway for processing visuospatial information by demonstrating dissociations in LTM systems for these two types of information. Lesions in the right MTL, adjacent to the cortical structures believed to be specialized for facial recognition, specifically impair the memory encoding of new faces, but not spatial locations.     

More is not necessarily better: Examining the nature of the temporal reference memory component in timing

Three experiments compared the timing performance of humans on a modified temporal generalization task with 1, 3, or 5 presentations of the standard duration. In all three experiments subjects received presentations of a standard duration at the beginning of a trial block and then had to judge whether each of a number of comparison stimuli was or was not the standard. The duration of the standard changed between blocks. The three experiments varied the experimental design (between or within subjects), task difficulty (how closely the comparison stimuli were spaced around the standards), and presence or absence of feedback on performance accuracy. Number of presentations of the standard never affected the proportion of identifications of the standard when it was presented, nor other features of the temporal generalization gradients observed. The implications for the operation of reference memories within the scalar timing system were explored via models that made different assumptions about how the individual presentations of the standard were stored and used.     

Memory for memory

Participants read short passages and 1 day later they answered questions via telephone about the passages (text facts) and about the experimental session (event facts). They were telephoned again 6 weeks later and answered the same questions about text and event facts. They also answered new questions about whether they remembered the answers they had given in the initial telephone interview (recall for prior memory performance). Although participants accurately remembered the majority of past memory successes, they were poor at remembering past memory failures. After being provided with the correct answer and tested again, the participants' performance improved somewhat, especially for memory failures. This suggests that some errors in recalling past forgetting might have been due to correctly remembering the answer previously given, but failing to realize that it had been wrong. These findings have implications for a variety of situations in which people are queried about past memory performance.     

Long-term memory for temporal structure:

In three experiments, long-term memory for temporal structure was examined by having participants identify both well-known (e.g., "I've Been Working on the Railroad") and novel songs. The target songs were subjected to a number of rhythmic alterations, to assess the importance of four critical features of identification performance. The four critical features were meter, phrasing, rhythmic contour (ordinal scaling of note durations), and the ratio of successive durations. In contrast with previous work, the unaltered version of each song was identified significantly better than any altered version. This indicates that rhythm is stored in long-term memory. Furthermore, the results demonstrated that all four critical features play a role in the identification of songs. These results held for both well-known and novel tunes.     

Overloading temporal memory

This study tested the hypothesis that memory is a major source of variance in temporal processing. Participants categorized intervals as short or long. The number of base durations and interval types mixed within blocks of trials varied from 1 session to another. Results revealed that mixing 2 base durations within blocks increased categorization errors, but mixing 2 marker types did not. Results are attributed to the involvement of more than 1 memory representation, which is argued to show the critical role of memory in temporal processing. Because mixing modalities has no such effect, it was argued that modalities share a common representation in memory. Finally, there was no difference in the perceived duration of auditory and visually marked intervals, which is inconsistent with most reports on this effect.     

Memory and consciousness: trace distinctiveness in memory retrievals

The aim of this article was to provide experimental evidence that classical dissociation between levels of consciousness associated with memory retrieval (i.e., implicit or explicit) can be explained in terms of task dependency and distinctiveness of traces. In our study phase, we manipulated the level of isolation (partial vs. global) of the memory trace by means of an isolation paradigm (isolated words among non-isolated words). We then tested these two types of isolation in a series of tasks of increasing complexity: a lexical decision task, a recognition task, and a free recall task. The main result of this study was that distinctiveness effects were observed as a function of the type of isolation (level of isolation) and the nature of the task. We concluded that trace distinctiveness improves subsequent access to the trace, while the level of trace distinctiveness also appears to determine the possibility of conscious or explicit retrieval.     

Memory in motion: Movement dynamics reveal memory strength

Recognition memory is typically examined as a discrete end-state, describable by static variables, such as accuracy, response time, and confidence. In the present study, we combined real-time mouse-tracking with subsequent, overt confidence estimates to examine the dynamic nature of memory decisions. By examining participants' streaming x-, y- mouse coordinates during recognition decisions, we observed that movement trajectories revealed underlying response confidence. More confident decisions were associated with shorter decision times and more linear response trajectories. Less confident decisions were made slowly, with increased trajectory curvature. Statistical indices of curvature and decision times, including area-under-the-curve and time to maximum deviation, suggested that memory strength relates to response dynamics. Whether participants were correct or incorrect, old responses showed a stronger correspondence between mouse trajectories and confidence, relative to new responses. We suggest that people subjectively experience a correspondence between feelings of memory and feelings of confidence; that subjective experience reveals itself in real-time decision processes, as suggested by sequential sampling models of recognition decisions.     

Spatial memory in rats: electroconvulsive shock selectively disrupts working memory but spares reference memory

In two experiments rats were trained until they displayed highly accurate spatial memories when a 4-h delay was imposed between the to-be-remembered event (TBRE) and the retention test in a 12-arm radial maze. If the procedure tested only working memory (WM) electronvulsive shock (ECS) 2 h after the TBRE produced amnesia but ECS immediately after the TBRE was ineffective. If the testing procedure also involved a reference memory (RM) component, ECS degraded WM regardless of whether it was given 0 or 2 h after the TBRE. RM was not affected. With either training procedure administering ECS 2 h before the TBRE was ineffective. Thus, in the radial maze truly old spatial RM was immune to disruption by ECS while more recent WM was vulnerable. Possible explanations of the data are presented.     

Memory systems in the rat: effects of reward probability,context, and congruency between working and reference memory

The interaction of working and reference memory was studied in rats on an eight-arm radial maze. In two experiments, rats were trained to perform working memory and reference memory tasks. On working memory trials, they were allowed to enter four randomly chosen arms for reward in a study phase and then had to choose the unentered arms for reward in a test phase. On reference memory trials, they had to learn to visit the same four arms on the maze on every trial for reward. Retention was tested on working memory trials in which the interval between the study and test phase was 15 s, 15 min, or 30 min. At each retention interval, tests were performed in which the correct WM arms were either congruent or incongruent with the correct RM arms. Both experiments showed that congruency interacted with retention interval, yielding more forgetting at 30 min on incongruent trials than on congruent trials. The effect of reference memory strength on the congruency effect was examined in Experiment 1, and the effect of associating different contexts with working and reference memory on the congruency effect was studied in Experiment 2.     

Medial temporal lobe memory in childhood: developmental transitions

The medial temporal lobes (MTL) support declarative memory and mature structurally and functionally during the postnatal years in humans. Although recent work has addressed the development of declarative memory in early childhood, less is known about continued development beyond this period of time. The purpose of this investigation was to explore MTL‐dependent memory across middle childhood. Children (6 –10 years old) and adults completed two computerized tasks, place learning (PL) and transitive inference (TI), that each examined relational memory, as well as the flexible use of relational learning. Findings suggest that the development of relational memory precedes the development of the ability to use relational knowledge flexibly in novel situations. Implications for the development of underlying brain areas and ideas for future neuroimaging investigations are discussed.     

Memory for actions: Enactment and source memory

Enacting simple action phrases enhances item memory but may not enhance other aspects of memory. The present experiment examines the effects of enactment on source memory. During the study phase, participants performed some actions (subject-performed tasks, SPTs) and observed the experimenter perform other actions (experimenter-performed tasks, EPTs). One group performed the SPTs with eyes closed, one group with eyes open (the standard condition), and one group performed SPTs facing a mirror (EPT presentation was constant across groups). As expected, item memory was better for SPTs than for EPTs. More importantly, source memory for SPTs was affected by the amount of visual feedback. As predicted by the source-monitoring framework, source memory for SPTs decreased as the amount of visual feedback increased from none (eyes closed) to moderate (standard condition) to maximal (mirror condition). In addition, SPT encoding failed to increase source memory and in one condition actually decreased source memory, relative to EPT encoding. Thus, enactment dissociated item and source memory, enhancing the former but not the latter.     

More is still not better: testing the perturbation model of temporal reference memory across different modalities and tasks

The ability of the perturbation model (Jones & Wearden, 2003) to account for reference memory function in a visual temporal generalization task and auditory and visual reproduction tasks was examined. In all tasks the number of presentations of the standard was manipulated (1, 3, or 5), and its effect on performance was compared. In visual temporal generalization the number of presentations of the standard did not affect the number of times the standard was correctly identified, nor did it affect the overall temporal generalization gradient. In auditory reproduction there was no effect of the number of times the standard was presented on mean reproductions. In visual reproduction mean reproductions were shorter when the standard was only presented once; however, this effect was reduced when a visual cue was provided before the first presentation of the standard. Whilst the results of all experiments are best accounted for by the perturbation model there appears to be some attentional benefit to multiple presentations of the standard in visual reproduction.     

More is still not better: Testing the perturbation model of temporal reference memory across different modalities and tasks

The ability of the perturbation model (Jones & Wearden, 2003) to account for reference memory function in a visual temporal generalization task and auditory and visual reproduction tasks was examined. In all tasks the number of presentations of the standard was manipulated (1, 3, or 5), and its effect on performance was compared. In visual temporal generalization the number of presentations of the standard did not affect the number of times the standard was correctly identified, nor did it affect the overall temporal generalization gradient. In auditory reproduction there was no effect of the number of times the standard was presented on mean reproductions. In visual reproduction mean reproductions were shorter when the standard was only presented once; however, this effect was reduced when a visual cue was provided before the first presentation of the standard. Whilst the results of all experiments are best accounted for by the perturbation model there appears to be some attentional benefit to multiple presentations of the standard in visual reproduction.     

Memory and memory confidence in obsessive-compulsive disorder

Pathological doubt, often found in individuals with obsessive-compulsive disorder (OCD), has been theoretically linked to memory deficits, but empirical evidence for such deficits has been mixed. In contrast, many studies suggest that individuals with OCD have low confidence in their memories. The present study aimed to build upon previous research by measuring memory accuracy and confidence in OCD using ecologically valid, idiographically-selected stimuli. Individuals with OCD (OCs), anxious controls (ACs), and nonanxious controls (NACs) were exposed to a set of objects that the OCs had identified as safe, unsafe, or neutral. Participants were then asked to recall as many objects as possible and to rate their confidence in each memory. This process was repeated 6 times, using the same stimuli for each trial. Contrary to hypothesis, no group differences emerged in memory accuracy. However, OCs' memory confidence for unsafe objects showed a progressive decline over repeated trials. This pattern was not observed among NACs or ACs. Furthermore, OCs with primary checking reported lower confidence in long-term memory than did OCs without primary checking. These results suggest that when OCs are repeatedly exposed to threat-related stimuli (such as repeated checking), their level of confidence in remembering these stimuli paradoxically decreases.     

Metamemory in temporal lobe epilepsy: Self-monitoring of memory functions

Temporal lobe seizure patients and control subjects participated in an investigation of metamemory. The two-part study explored the individual's perception of memory abilities for both encoding and retrieval. Experiment I addressed self-monitoring of encoding through a study of prediction of memory span. Experiment II explored self-monitoring of retrieval through a study of "Feeling of Knowing." The results indicate that left and right temporal lobe seizure patients tend to overestimate their memory capacities, in comparison with normal controls, and that self-monitoring tends to be less accurate for material (verbal or nonverbal) mediated by side of lesion. The potential impact of inaccurate memory monitoring on the memory dysfunction observed in seizure patients is discussed.     

Memory Functioning Questionnaire: concurrent validity with memory performance and self-reported memory failures

Concurrent validity of factor scores from the Memory Functioning Questionnaire (MFQ; Gilewski, Zelinski, & Schaie, in press) with memory performance was investigated in 2 studies. Study 1 involved 198 adults aged 55-85; Study 2, 89 adults aged 50-87. After effects of depression, education, and health were partialed out, MFQ scores predicted performance on laboratory memory tests in Study 1 and performance on clinical memory tests and diaries of memory failures over 2 weeks in Study 2. Additional variance in predicting performance and failures recorded in diaries is accounted for by MFQ scores after partialing out subjects' responses to a yes-no question about whether they have memory problems. Results suggest that the MFQ has moderate concurrent validity with memory measures and is preferable to responses to a single question about memory self-perception in assessing memory complaints in normal adults.     

Memory anxiety and memory performance in adulthood

The present study examined the contribution of general and domain-specific anxiety to the prediction of memory performance in a sample of 350 young, middle-aged and old adults. In a preliminary stage of this investigation, psychometric analyses revealed that the predictive validity of the Anxiety scale of the Metamemory in Adulthood questionnaire, used to assess memory-related anxiety, could be improved by using an abbreviated version of the scale. This Memory Anxiety subscale predicted level of state anxiety experienced by middle-aged and older subjects in anticipation of a memory-demanding task. It was superior to the general state measures in predicting actual memory performance, but only for the oldest age group. Results thus provide support for domain- and age-specificity in the assessment of anxiety performance relationships.     

Memory for temporal order in novel sequential action

ABSTRACT

Order is critical for many daily activities. Developmental research has shown that memory for order in action is the least prioritised in a processing hierarchy, and is sensitive to deviant input. The current research investigated these aspects of sequence learning are also present in adults. Participants learned a novel sequence across several exemplars with either easy- or difficult-to-categorize items, which either did or did not involve a deviant order on one exemplar, and were later asked to recall the sequence. Memory for individual sub-actions and order was stronger in the easy conditions, and the deviant order significantly deteriorated ordered recall in the difficult condition only. These findings support the theorised processing hierarchy, with the presence of a deviant order having a larger effect on memory when the load at the earlier item stage is increased. These results have implications for theories of working memory and learning in real-world contexts.