The personalisation method applied to a working memory task: Evidence of long-term working memory effects

Ericsson and Kintsch (1995) proposed that, in situations of expertise, individuals can overcome working memory limitations by using long-term working memory. It allows a greater capacity than working memory thanks to long-term memory encoding and retrieving. To test this characteristic, an adaptation of Daneman and Carpenter's (1980) reading span was used. To operationalise expertise, the personalisation method (Guida & Tardieu, 2005) was employed. In Experiment 1, a personalised group, which read reading span sentences that mentioned familiar locations, was compared to a nonpersonalised group, which read sentences with unfamiliar locations. In Experiment 2, a personalised group, which read reading span sentences with neutral locations, was encouraged to mentally personalise these locations by thinking about known locations. This group was compared to a nonpersonalised group, which was encouraged to think about unknown locations. The personalised groups were expected to store and retrieve information in long-term memory via long-term working memory more easily than the nonpersonalised groups, which had to count massively on working memory. The results showed that personalisation enhanced reading span and confirmed one implication of the long-term working memory theory: high- and low-reading-span differences could also be due to long-term memory retrieval. Finally, these results are interpreted in terms of interaction between working memory size and long-term memory knowledge, showing that participants with a lower reading span benefited more from high domain knowledge than participants with a higher reading span.     

Different working memory capacity in normal young adults for visual and tactile letter recognition task

Thirty-nine young adult participants performing the visual and tactile n-back working memory task were compared. In the visual task, letters were presented on a computer screen and in the tactile task, plastic letters embedded on a board were explored tactually. The amount of incorrect responses increased with increasing memory load in both tasks, but was significantly lower in the visual task. Subgrouping the participants with extreme performances into "skilled" and "poor" performers showed that the best performance was found among "skilled" visual performers, and the worst one among "poor" tactile performers. There was more interindividual variation among tactile than visual performance. We conclude that tactile working memory capacity, measured here by letter recognition and letter memory, is generally more limited and shows more variability than visual memory in normal sighted participants.     

Prospective memory and aging: The effects of working memory and prospective memory task load

Abstract

A person's level of engagement in other actions may influence whether a prospective action is correctly performed. This study used a computerized prospective memory task in which participants remembered to perform an action when a specified background pattern appeared while they simultaneously performed a verbal working memory task. Amount of engagement in the working memory task was manipulated by increasing the number of words to be recalled. Prospective memory load was manipulated by varying the number of prospective targets. Older adults performed more poorly than younger adults on the prospective memory task under higher working memory load and also higher prospective load. Participants with lower working memory load performed better on the prospective task, regardless of age. There were no significant age differences in the absolute accuracy of performance postdictions (post experiment performance awareness). Age differences were also found with a second prospective memory task in which participants were told to write the day of the week (DOW) on the top of answer sheets for tasks performed later in the experiment. No significant correlations were observed between the two prospective memory tasks for either age group.     

The influence of story context on a working memory span task

The purpose of the present study was to examine factors that could influence whether recall performance in the reading span task (Daneman & Carpenter, 1980 ) would benefit from the contextual information from the sentences in the processing component of the task. More specifically, we investigated whether people would benefit from sentence sets that formed short stories or when the entire span task was one continuous story. Overall, there was a clear benefit for contextually related sentence sets (i.e., the story span tasks) compared to the traditional reading span task. However, the benefit was eliminated when the entire set formed one continuous story. These results support the recall reconstruction hypothesis for working memory (Towse, Cowan, Hitch, & Horton, 2008 ), which suggests that people may strategically use the content of the sentences from the processing component of the reading span task as memorial cues to reconstruct the target words of the storage component. However, this benefit is constrained to scenarios when the contextual cues are unique to a specific set.     

The influence of story context on a working memory span task

The purpose of the present study was to examine factors that could influence whether recall performance in the reading span task (Daneman & Carpenter, 1980 Daneman, M. and Carpenter, P. 1980. Individual differences in working memory and reading. Journal of Verbal Learning and Verbal Behavior, 19: 450–466. [Crossref] , [Google Scholar]) would benefit from the contextual information from the sentences in the processing component of the task. More specifically, we investigated whether people would benefit from sentence sets that formed short stories or when the entire span task was one continuous story. Overall, there was a clear benefit for contextually related sentence sets (i.e., the story span tasks) compared to the traditional reading span task. However, the benefit was eliminated when the entire set formed one continuous story. These results support the recall reconstruction hypothesis for working memory (Towse, Cowan, Hitch, & Horton, 2008 Towse, J. N., Cowan, N., Hitch, G. J. and Horton, N. J. 2008. The recall of information from working memory: Insights from behavioural and chronometric perspectives. Experimental Psychology, 55: 371–383. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]), which suggests that people may strategically use the content of the sentences from the processing component of the reading span task as memorial cues to reconstruct the target words of the storage component. However, this benefit is constrained to scenarios when the contextual cues are unique to a specific set.     

The effects of total sleep deprivation on the generation of random sequences of key-presses, numbers and nouns

According to a recent hypothesis, executive functions should be particularly vulnerable to the effects of total sleep deprivation. Random generation is a task that taps executive functions. In three experiments we examined the effects of total sleep deprivation on random generation of keypresses, numbers, and nouns, in particular on the suppression of prepotent responses and the selection of next responses by way of applying a local-representativeness heuristic. With random key-presses suppression of prepotent responses did not suffer from lack of sleep, but it became poorer at a sufficiently high pacing rate. In contrast, suppression of prepotent responses suffered when numbers and nouns were generated. According to these findings different types of random generation tasks involve different types of inhibitory process. With only four response alternatives, but not with larger response sets, application of the local-representativeness heuristic was impaired after a night without sleep. In terms of a simple formal model, serial-order representations of the preceding responses are used in selecting the next response only for the small response set, and not for larger response sets. Thus, serial-order representations are likely to suffer from loss of sleep. These findings strongly suggest that random generation involves multiple processes and that total sleep deprivation does not impair all sorts of executive functions, but only some.     

Roles of working memory capacity and long-term working memory skill in complex task performance

In the present research, we examined the relative roles of domain-general and domain-specific individual difference characteristics in complex cognitive task performance. Specifically, we examined the impact both of working memory (WM) capacity and of acquired skills used to encode presented information in an accessible form in long-term working memory (LTWM) on performance in a complex aviation task environment. Measures of WM capacity and LTWM skill served as performance predictors. A criterion measure of task performance was related to the predictor measures. The results indicated that an increase in LTWM skill decreases the role of WM capacity as the determinant of complex task performance, although both measures are important performance predictors. We discuss how the two distinct WM constructs coexist and interact to support complex task performance.     

Effects of sleep deprivation on auditory and visual memory tasks

Probe recognition tasks have shown the effects of sleep deprivation following a full night of sleep loss. The current study investigated shorter durations of deprivation by testing 11 subjects for accuracy and response time every 2 hr. from 10 p.m. through 8 a.m. We replicated Elkin and Murray's auditory single-probe recognition task using the number triplets and added two visual tasks with number and shape triplets. Series of six stimuli were each followed by a probe, which was presented after 2.5 sec. as a short delay or 20 sec. as a long delay. Accuracy performance showed a significant decrease for the long delay beginning after 4 a.m. for the two visual tasks. Response times were significantly slower for the visual shapes task using the short delay. Visual tasks, especially shapes, may be more prone to disruption by sleep deprivation, given the visual information load and the briefness of iconic memory.     

Effects of sleep deprivation on short-term recognition memory.

A probe-recognition short-term memory paradigm was used to inquire into the precise effects of sleep deprivation on human memory. It was found that recognition performance, as measured by d', was generally impaired for each subjects after 24 hr of sleep deprivation. While d' was shown to decrease exponentially as the number of items intervening between the target and the probe increased, this decay rate was not affected by sleep loss. In addition there was confirmation of a previously observed increase in the positive skewness of reaction times after wakefulness. The data were consistent with the hypothesis that sleep deprivation increases the occurrence of lapses, periods of lowered reactive capacity, which prevent the encoding of items in short-term memory.     

Neural substrates of successful working memory and long-term memory formation in a relational spatial memory task

Working memory (WM) tasks may involve brain activation actually implicated in long-term memory (LTM). In order to disentangle these two memory systems, we employed a combined WM/LTM task, using a spatial relational (object-location) memory paradigm and analyzed which brain areas were associated with successful performance for either task using fMRI. Critically, we corrected for the performance on the respective memory task when analyzing subsequent memory effects. The WM task consisted of a delayed-match-to-sample task assessed in an MRI scanner. Each trial consisted of an indoor or outdoor scene in which the exact configuration of four objects had to be remembered. After a short delay (7–13 s), the scene was presented from a different angle and spatial recognition for two objects was tested. After scanning, participants received an unexpected subsequent recognition memory (LTM) task, where the two previously unprobed objects were tested. Brain activity during encoding, delay phase and probe phase was analyzed based on WM and LTM performance. Results showed that successful WM performance, when corrected for LTM performance, was associated with greater activation in the inferior frontal gyrus and left fusiform gyrus during the early stage of the maintenance phase. A correct decision during the WM probe was accompanied by greater activation in a wide network, including bilateral hippocampus, right superior parietal gyrus and bilateral insula. No voxels exhibited supra-threshold activity during the encoding phase, and we did not find any differential activity for correct versus incorrect trials in the WM task when comparing LTM correct versus LTM incorrect trials.     

Effects of task duration on sensitivity to sleep deprivation using the multi-attribute task battery

Several factors affect the sensitivity to sleep deprivation in the performance of computerized tests. Two of these are task complexity and duration. Complexity can improve sensitivity by increasing the demands required to complete the task, but it can also decrease sensitivity by improving the subject’s motivation. The effects of task duration are more predictable in that longer tests generally are more susceptible to deprivation effects than shorter ones. The impact of task duration on an interesting, but complex, aviation simulation was examined here. By breaking down data from 30-min multi-attribute task battery administrations into the first, second, and third 10 min of performance, it was shown that tests shorter than 30 min underestimate the impact of sleep loss on performance. This was especially evident in measures of time-out and tracking errors.     

Training the removal of negative information from working memory: A preliminary investigation of a working memory bias modification task

Rumination in depressed adults is associated with a bias toward retaining negative information in working memory. We developed a task designed to modify this cognitive bias by having subjects repeatedly practice removing negative words from working memory, thereby enabling them to retain positive and neutral words. To assess the efficacy of this task, we recruited 60 adults who reported elevated repetitive negative thought (RNT) and randomly assigned them to receive a single administration of either the working memory bias modification (WMBM) task or a control task. Subjects in the WMBM condition exhibited greater reduction in proactive interference for negative information than did those in the control condition. These results suggest that the WMBM task reduces biased retention of negative information in working memory and, thus, may be useful in investigating the possible causal role of this cognitive bias in RNT or depression.     

The nature of inhibition in a working memory search task

Inhibition is one of the key processes that regulate working memory (WM) activity. The main research question concerned the nature of inhibition of highlighted information in WM. The study was designed to examine two competing hypotheses. The first assumed that inhibition is carried out by deletion of irrelevant information from the focus of attention (cognitive inhibition account). An alternative hypothesis assumed that it is the response to a correctly recognised stimulus that is inhibited (effortful response inhibition account). Two experiments with a spatial modification of the WM serial search task were conducted wherein two factors were manipulated: serial order of the items, and distance from the central fixation point. In both experiments, higher response time was correlated with a smaller distance from the fixation point. The inhibited items were recognised equally efficiently or better than the uninhibited items. The results support the effortful response inhibition account over the cognitive inhibition account.     

A group-administered lag task as a measure of working memory

The purpose of the present studies was to evaluate the utility of a group-administered version of the n-back, or lag task. Experiments 1 and 2 describe the construction of the task and reveal that the modified lag task (MLT) produces the same performance trends as have been observed in individually administered versions of the lag task; performance decreased significantly as lag conditions increased in difficulty. Experiments 3 and 4 established convergent validity by comparing the MLT to another common working memory task, the operation-word span task, as well as the updated version of this task, the automatic operation span task. The results showed that MLT performance was significantly correlated to scores on both measures. These experiments provide important details about the MLT as a measure of working memory, in a group- or individual-administration setting.     

Minimal use of working memory in a scene comparison task

Eye movement behaviour in hand-eye tasks suggests a preference for a “just in time” processing strategy that minimizes the use of working memory. In the present study, a scene comparison task was introduced to determine whether the preference holds when the task is primarily visual and when more complex naturalistic scenes are used as stimuli. In two experiments, participants made same or different judgements in response to simultaneously presented pairs of scenes that were identical or differed by one object. The number of fixations per scene glance and the number of fixations intervening between glances to corresponding objects suggest that frequently one object at a time is encoded and maintained in visual working memory. The same pattern of results was observed in a third experiment using word and object arrays. Overall, the results suggest a strong general bias toward minimal use of visual working memory in complex visual tasks.     

When working memory updating requires updating: Analysis of serial position in a running memory task

This study aimed to investigate updating in working memory (WM), analyzing the effects of task demand and memory resources on serial position curve (SPC), in a running memory task with slow pace presentation and a probed recognition procedure. These task conditions were supposed to produce an easier WM updating task, which may allow evidencing whether the task is performed through an active or a passive updating.     

Olfactory working memory: effects of verbalization on the 2-back task

Working memory for odors, which has received almost no attention in the literature, was investigated in two experiments. We show that performance in a 2-back task with odor stimuli is well above chance. This is true not only for highly familiar odors, as has been shown by Dade, Zatorre, Evans, and Jones-Gotman, NeuroImage, 14, 650–660, (2001), but also for unfamiliar ones that are notoriously difficult to name. We can conclude that information about an olfactory stimulus can be retained in the short term and can continuously be updated for comparison with new olfactory probes along the lines of a functional odor working memory. However, the performance in the working memory task is highly dependent on participants’ verbalization of the odor. In addition, results indicated that odor working memory performance is dependent on the ability to discriminate among the odor stimuli (Experiment 2). The results are discussed in relation to recent ideas of a separate olfactory working memory slave system.     

The effect of a subsidiary task on iconic memory

Memory & Cognition - Using a subsidiary task technique, Doest and Turvey (1971) concluded that iconic memory was independent of the central processing system. However, they did not control the...