Similarities and differences between working memory and long-term memory: Evidence from the levels-of-processing span task.

Two experiments compared the effects of depth of processing on working memory (WM) and long-term memory (LTM) using a levels-of-processing (LOP) span task, a newly developed WM span procedure that involves processing to-be-remembered words based on their visual, phonological, or semantic characteristics. Depth of processing had minimal effect on WM tests, yet subsequent memory for the same items on delayed tests showed the typical benefits of semantic processing. Although the difference in LOP effects demonstrates a dissociation between WM and LTM, we also found that the retrieval practice provided by recalling words on the WM task benefited long-term retention, especially for words initially recalled from supraspan lists. The latter result is consistent with the hypothesis that WM span tasks involve retrieval from secondary memory, but the LOP dissociation suggests the processes engaged by WM and LTM tests may differ. Therefore, similarities and differences between WM and LTM depend on the extent to which retrieval from secondary memory is involved and whether there is a match (or mismatch) between initial processing and subsequent retrieval, consistent with transfer-appropriate-processing theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex influence on face recognition memory moderated by presentation duration and reencoding.

Objective: It has been suggested that women have a better face recognition memory than men. Here we analyzed whether this advantage depends on a better encoding or consolidation of information and if the advantage is visible during short-term memory (STM), only, or whether it also remains evident in long-term memory (LTM). Method: We tested short- and long-term face recognition memory in 36 nonclinical participants (19 women). We varied the duration of item presentation (1, 5, and 10 s), the time of testing (immediately after the study phase, 1 hr, and 24 hr later), and the possibility to reencode items (none, immediately after the study phase, after 1 hr). Results: Women showed better overall face recognition memory than men (ηp2 = .15, p     

Social recognition memory requires protein synthesis after reactivation.

Recent evidence indicates that reactivation of consolidated memories returns them to a protein-synthesis-dependent state called reconsolidation. The hypothesis that memories reconsolidate has never been assessed in social memory. The authors tested whether sheep (Ovis aries) mothers' memory of their lambs undergoes reconsolidation upon reactivation. After 7 days of mother-young contact, ewes were separated from their lambs for 8 hr, after which the lambs were reintroduced to their mothers for a 10-min reactivation session. Before reactivation, mothers received a subcutaneous injection of either the protein-synthesis inhibitor cycloheximide (CY, 1 mg/kg) or vehicle. Mothers' lamb memory was tested 1 hr (short-term memory [STM]) or 16 hr (long-term memory [LTM]) after reactivation. Mothers treated with CY exhibited intact STM but deficient LTM. CY injection without reactivation or before presentation of an alien lamb induced no deficit in LTM. CY-induced LTM deficit was alleviated by (a) introducing a reminder just before the LTM test, (b) extending mother-young contact, and (c) preventing suckling by the familiar lamb during reactivation. Thus, reconsolidation can be shown to exist in social memory, and some of its boundary conditions are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Control of the Contents of Working Memory--A Comparison of Two Paradigms and Two Age Groups.

Two experiments investigated whether young and old adults can temporarily remove information from a capacity-limited central component of working memory (WM) into another component, the activated part of long-term memory (LTM). Experiment 1 used a modified Sternberg recognition task (S. Sternberg, 1969); Experiment 2 used an arithmetic memory-updating task. In both paradigms, participants memorized 2 lists, one of which was cued as temporarily irrelevant. Removal of the irrelevant list from capacity-limited WM was indexed by the disappearance of list-length effects of that list on latencies for concurrent processing tasks. Young adults could outsource the irrelevant list within 2-3 s and retrieve it back into the central part of WM later. Old adults showed the same flexibility in the arithmetic updating task but seemed somewhat less able or inclined to temporarily move information into the activated part of LTM in the modified Sternberg task. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Turning simple span into complex span: Time for decay or interference from distractors?

We investigated the effects of the duration and type of to-be-articulated distractors during encoding of a verbal list into short-term memory (STM). Distractors and to-be-remembered items alternated during list presentation, as in the complex-span task that underlies much of working-memory research. According to an interference model of STM, known as serial order in a box (SOB; Farrell & Lewandowsky, 2002), additional repeated articulations of the same word between list items should cause minimal further disruption of encoding into STM even though the retention interval for early list items is increased. SOB also predicts that the articulation of several different distractor items should lead to much enhanced disruption if the distractor interval is increased. Those predictions were qualitatively confirmed in 4 experiments that found that it is the type of distractors, not their total duration, that determines the success of encoding a list into STM. The results pose a challenge to temporal models of complex-span performance, such as the time-based resource sharing model (Barrouillet, Bernardin, & Camos, 2004). The results add to a growing body of evidence that memory for the short term is not exclusively governed by purely temporal processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Embodied memory judgments: A case of motor fluency.

It is well known that perceptual and conceptual fluency can influence episodic memory judgments. Here, the authors asked whether fluency arising from the motor system also impacts recognition memory. Past research has shown that the perception of letters automatically activates motor programs of typing actions in skilled typists. In this study, expert typists made more false recognition errors to letter dyads which would be easier or more fluent to type than nonfluent dyads, while no typing action was involved (Experiment 1). This effect was minimized with a secondary motor task that implicated the same fingers that would be used to type the presented dyads, but this effect remained with a noninterfering motor task (Experiment 2). Typing novices, as a comparison group, did not show fluency effects in recognition memory. These findings suggest that memory is influenced by covert simulation of actions associated with the items being judged—even when there is no intention to act—and highlight the intimate connections between higher level cognition and action. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

True memory, false memory, and subjective recollection deficits after focal parietal lobe lesions.

Objective: There is mounting evidence that the posterior parietal cortex (PPC) plays an important role in episodic memory. We previously found that patients with PPC damage exhibit retrieval-related episodic memory deficits. Here we assess whether parietal lobe damage affects episodic memory on a different task: the Deese–Roediger–McDermott (DRM) false-memory paradigm. Methods: Two patients with bilateral PPC damage and a group of matched controls were tested. In Experiment 1, the task was to remember words; in Experiment 2 the task was to remember pictures of common objects. Prior studies have shown that normal participants have high levels of false memory to words, low levels to pictures. Results: The patients exhibited significantly lower levels of false memory to words. One patient showed significantly elevated levels of false memory to pictures. The patients' false memories were accompanied by reduced levels of recollection, as tested by a Remember/Know procedure. Conclusions: PPC damage causes decreased levels of false memories and an abnormal Remember/Know profile. Their false memory rate is similar to the rate exhibited by patients with medial temporal lobe damage. These results support the view that portions of the PPC play a critical role in objective and subjective aspects of recollection. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory for gist and detail information in Alzheimer's disease and mild cognitive impairment.

Two experiments examined different forms of gist and detail memory in people with Alzheimer's disease (AD) and those with amnestic mild cognitive impairment (MCI). In Experiment 1, 14 AD, 14 MCI, and 22 control participants were assessed with the Deese-Roediger-McDermott paradigm. Results indicated that false recognition of nonstudied critical lures (gist memory) was diminished in the AD compared with the MCI and control groups; the two latter cohorts performed similarly. In Experiment 2, 14 AD, 20 MCI, and 26 control participants were tested on a text memory task. Results revealed that recall of both macropropositions (gist information) and micropropositions (detail information) decreased significantly in AD and in MCI as compared with control participants. This experiment also revealed that the impairment was comparable between gist and detail memory. In summary, the results were consistent across experiments in the AD but not in the MCI participants. The discrepancy in MCI participants might be explained by differences in the degree of sensitivity of the experimental procedures and/or by the differences in the cognitive processes these procedures assessed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age-related deficits in component processes of working memory.

Working memory deficits in normal aging have been well documented, and studies suggest that high memory load plus the presence of distraction negatively impacts successful memory performance to a greater degree in older individuals. However, characterization of the component processes that are impaired by these task manipulations is not clear. In this behavioral study, younger and older subjects were tested with a delayed-recognition and recall task in which the encoding and delay period were both manipulated. During the encoding period, the subjects were presented with either a single letter or multiple letters at their predetermined forward letter span, and the delay period was either uninterrupted or interrupted with a visual distraction. There was an age-related impairment of working memory recognition accuracy only in the combination of high memory load and distraction. These results suggest that when working memory maintenance systems are taxed, faulty recognition processes may underlie cognitive aging deficits in healthy older individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of Orthographic and Phonological Word Length on Memory for Lists Shown at RSVP and STM Rates.

This article reports 3 experiments in which effects of orthographic and phonological word length on memory were examined for short lists shown at rapid serial visual presentation (RSVP) and short-term memory (STM) rates. Only visual-orthographic length reduced RSVP serial recall, whereas both orthographic and phonological length lowered recall for STM lists in Experiment 1. Word-length effects may arise from output processes or from the temporal duration of output in recall. In 2 further experiments, output demands were reduced through the use of a recognition test. Recognition accuracy was impaired only by orthographic length for RSVP lists and by phonological length for STM lists in both experiments. The results demonstrate 2 item length effects not simply attributable to increased output time in recall, and implications for theories of STM are considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Functional Frontoparietal Connectivity During Short-Term Memory as Revealed by High-Resolution EEG Coherence Analysis.

In this electroencephalographic study, the authors modeled the functional connectivity between frontal and parietal areas during short-term memory (STM) processes by spectral coherence analysis and the directed transfer function, that is, for the estimation of coherence "direction." A no-STM task was used as a reference. STM was characterized by an increased frontoparietal electroencephalograph coherence at high frequencies (beta and gamma, 14-45 Hz). In the control task, parietal-to-frontal flow prevailed at those frequencies. However, the STM task showed a bidirectional frontoparietal flow at the gamma band. In conclusion, frontoparietal connectivity would optimize "representational" memory during STM. In this context, the frontal areas would increase their influence on parietal areas for memory retention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The low-frequency encoding disadvantage: Word frequency affects processing demands.

Low-frequency words produce more hits and fewer false alarms than high-frequency words in a recognition task. The low-frequency hit rate advantage has sometimes been attributed to processes that operate during the recognition test (e.g., L. M. Reder et al., 2000). When tasks other than recognition, such as recall, cued recall, or associative recognition, are used, the effects seem to contradict a low-frequency advantage in memory. Four experiments are presented to support the claim that in addition to the advantage of low-frequency words at retrieval, there is a low-frequency disadvantage during encoding. That is, low-frequency words require more processing resources to be encoded episodically than high-frequency words. Under encoding conditions in which processing resources are limited, low-frequency words show a larger decrement in recognition than high-frequency words. Also, studying items (pictures and words of varying frequencies) along with low-frequency words reduces performance for those stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Overdependence on degraded gist memory in Alzheimer's disease.

Alzheimer's disease (AD) reduces associative effects on false recognition in the Deese-Roediger-McDermott task, either due to impaired memory for gist or impaired use of gist in memory decisions. Gist processes were manipulated by blocking or mixing studied words according to their associations and by varying the associative strength between studied and nonstudied words at test. Both associative blocking and associative strength had smaller effects on false recognition in AD patients than in control participants, consistent with gist memory impairments. However, unlike the case with control participants, blocking influenced true and false recognition equally in AD patients, demonstrating an overdependence on gist when making memory decisions. AD also impaired item-specific recollections, relative to control participants, as true recognition of studied words was reduced even when the two groups were equated on gist-based false recognition. We propose that the overdependence on degraded gist memory in AD is caused by even larger impairments in item-specific recollections. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Working memory and the vividness of imagery.

The working memory framework was used to investigate the factors determining the phenomenological vividness of images. Participants rated the vividness of visual or auditory images under control conditions or while performing tasks that differentially disrupted the visuospatial sketchpad and phonological loop subsystems of working memory. In Experiments 1, 2, and 6, participants imaged recently presented novel visual patterns and sequences of tones; ratings of vividness showed the predicted interaction between stimulus modality and concurrent task. The images in experiments 3, 4, 5, and 6 were based on long-term memory (LTM). They also showed an image modality by task interaction, with a clear effect of LTM variables (meaningfulness, activity, bizarreness, and stimulus familiarity), implicating both working memory and LTM in the experience of vividness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental reversals in false memory: Now you see them, now you don't!

A developmental reversal in false memory is the counterintuitive phenomenon of higher levels of false memory in older children, adolescents, and adults than in younger children. The ability of verbatim memory to suppress this age trend in false memory was evaluated using the Deese-Roediger-McDermott (DRM) paradigm. Seven and 11-year-old children studied DRM lists either in a standard condition (whole words) that normally produces high levels of false memory or in an alternative condition that should enhance verbatim memory (word fragments). Half the children took 1 recognition test, and the other half took 3 recognition tests. In the single-test condition, the typical age difference in false memory was found for the word condition (higher false memory for 11-year-olds than for 7-year-olds), but in the word fragment condition false memory was lower in the older children. In the word condition, false memory increased over successive recognition tests. Our findings are consistent with 2 principles of fuzzy-trace theory's explanation of false memories: (a) reliance on verbatim rather than gist memory causes such errors to decline with age, and (b) repeated testing increases reliance on gist memory in older children and adults who spontaneously connect meaning across events. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Serial-order short-term memory predicts vocabulary development: Evidence from a longitudinal study.

Serial-order short-term memory (STM), as opposed to item STM, has been shown to be very consistently associated with lexical learning abilities in cross-sectional study designs. This study investigated longitudinal predictions between serial-order STM and vocabulary development. Tasks maximizing the temporary retention of either serial-order or item information were administered to kindergarten children aged 4 and 5. At age 4, age 5, and from age 4 to age 5, serial-order STM capacities, but not item STM capacities, were specifically associated with vocabulary development. Moreover, the increase of serial-order STM capacity from age 4 to age 5 predicted the increase of vocabulary knowledge over the same time period. These results support a theoretical position that assumes an important role for serial-order STM capacities in vocabulary acquisition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of short-term memory codes on visual image processing: Evidence from image transformation tasks.

Three experiments showed that phonological recoding of visual stimuli in short-term memory affects coding in long-term memory (LTM) and therefore performance on tasks involving generation and manipulation of visual images of the stimuli. An image transformation task was devised. It consists of mentally subtracting a part of an image to discover in the remainder another object. In Exp 1, Ss were required to learn a set of easily nameable visual stimuli and then perform the subtraction task on images retrieved from LTM. Performance was significantly better when initial learning was accompanied by articulatory suppression (AS). Exp 2 confirmed that AS had no effect when the task was performed on an image of a just-presented stimulus. In Exp 3, the nameability of the stimuli was manipulated. The results replicated the effect of AS for items that were easy to name but showed no effect of AS for stimuli that were difficult to name. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dissociable roles of dopamine within the core and medial shell of the nucleus accumbens in memory for objects and place.

There is increasing focus on the role of the nucleus accumbens (NAc) in learning and memory, but there is little consensus as to how the core and medial shell subregions of the NAc contribute to these processes. In the current experiments, we used spontaneous object recognition to test rats with 6-hydroxydopamine lesions targeted at the core or medial shell of the NAc on a familiarity discrimination task and a location discrimination task. In the object recognition variant, control animals were able to discriminate the novel object at both 24-hr and 5-min delay. However, in the lesion groups, performance was systematically related to dopamine (DA) levels in the core but not the shell. In the location recognition task, sham-operated animals readily detected the object displacement at test. In the lesion groups, performance impairment was systematically related to DA levels in the shell but not the core. These results suggest that dopamine function within distinct subregions of the NAc plays dissociable roles in the modulation of memory for objects and place. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Theoretical Correlations and Measured Correlations: Relating Recognition and Recall in Four Distributed Memory Models.

This article addresses the relation between item recognition and associative (cued) recall. Going beyond measures of performance on each task, the analysis focuses on the degree to which the contingency between successful recognition and successful recall of a studied item reflects the commonality of memory processes underlying the recognition and recall tasks. Specifically, 4 classes of distributed memory models are assessed for their ability to account for the relatively invariant correlation (≈ .5) between successive recognition and recall. Basic versions of each model either under- or overpredict the intertask correlation. Introducing variability in goodness-of-encoding and response criteria, as well as output encoding, enabled all 4 models to reproduce the moderate intertask correlation and the increase in correlation observed in 2 mixed-list experiments. This model-based analysis provides a general theoretical framework for interpreting contingencies between successive memory tests. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Multinomial Model of Event-Based Prospective Memory.

Prospective memory is remembering to perform an action in the future. The authors introduce the 1st formal model of event-based prospective memory, namely, a multinomial model that includes 2 separate parameters related to prospective memory processes. The 1st measures preparatory attentional processes, and the 2nd measures retrospective memory processes. The model was validated in 4 experiments. Manipulations of instructions to place importance on either the prospective memory task or the background task (Experiments 1 and 2) and manipulations of distinctiveness of prospective memory targets (Experiment 2) had expected effects on model parameters, as did a manipulation of the difficulty of prospective memory target encoding (Experiments 3 and 4). An alternative model was also evaluated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)