Age-related differences in the removal of information from working memory.

Removal has been assumed to be a core mechanism in working memory. However, it remains unclear whether children can actively remove outdated information from working memory and how this ability develops as children age. The current study aimed to examine age-related differences in removal ability and its relations with cognitive control and working memory capacity. Children aged 7, 9, and 11 years performed a modified working memory updating task assessing removal efficiency. In addition, a battery of cognitive control and working memory capacity tasks was administered. Results indicated that updating response times decreased considerably when a longer time was given for removal, suggesting that children aged 7 to 11 years can actively remove outdated items from working memory prior to encoding the new ones and that removal efficiency increased with age. More important, age-related increases in removal efficiency occurred concurrently with the development of working memory capacity. Proactive control predicted removal efficiency over and beyond age and working memory capacity. The findings shed new light on the mechanisms underlying the development of working memory updating.

Successful alpha neurofeedback training enhances working memory updating and event-related potential activity.

Neurofeedback (NF) is a promising method to self-regulate human brain activity for cognition enhancement. Due to the unclear results of alpha NF training on working memory updating as well as the impact of feedback modality on NF learning, this study aimed to understand further the underlying neural mechanism of alpha NF training effects on working memory updating, where the NF learning was also compared between visual and auditory feedback modalities. A total of 30 participants were assigned to Visual NF, Auditory NF, and Control groups. Working memory updating was evaluated by n-back (n =2,3) tasks before and after five alpha upregulation NF sessions. The result showed no significant difference in NF learning performance between the Visual and Auditory groups, indicating that the difference in feedback modality did not affect NF learning. In addition, compared to the control group, the participants who achieved successful NF learning showed a significant increase in n-back behavioral performance and P3a amplitude in 2-back and a significant decrease in P3a latency in 3-back. Our results in n-back further suggested that successful alpha NF training might improve updating performance in terms of the behavioral and related event-related potential (ERP) measures. These findings contribute to the understanding of the effect of alpha training on memory updating and the design of NF experimental protocol in terms of feedback modality selection.

Metacognition in working memory: Confidence judgments during an n-back task.

Metacognition in working memory (WM) has received less attention than episodic memory, and few studies have investigated confidence judgements while carrying out a verbal WM task. The present study investigated whether individuals are aware of their own level of performance while carrying out an ongoing verbal WM task, and whether judgments of confidence are sensitive to factors that determine WM performance. A verbal n-back task was adapted to obtain confidence judgments on a trial-by-trial basis. Memory load and lure interference were manipulated. Results showed that metacognition judgments were affected by memory load and levels of interference just as performance accuracy. Even when judgments were sensitive to memory factors, participants were overconfident and generally showed poor metacognitive accuracy at discriminating between erroneous and accurate responses. Results are discussed in terms of possible cues contributing to metacognitive judgements during an ongoing WM task and reasons for WM metacognitive accuracy.

Recollection contributes to children's reading comprehension: Using the process dissociation procedure in a working memory updating task.

Recollection, rather than familiarity, seems to play a crucial part in sustaining children's reading comprehension. However, the roles of recollection and familiarity in both word reading and reading comprehension have yet to be fully understood. In this study, we examined estimates of recollection and familiarity in a working memory updating task using an adaptation of the process dissociation procedure. Our study involved 204 children aged 9-11 years. We administered a keeping track task in which lists of words belonging to various semantic categories (e.g., animals) were presented. The children had to follow two sets of instructions: (a) inclusion, which involved saying whether they had seen a word during the previous learning phase, and b) exclusion, which involved saying whether a word was the last one they had seen that belonged to a given category. Our results showed that recollection contributed to explain reading comprehension, but not word reading, performance. Familiarity, instead, did not predict either of the reading measures (word reading or reading comprehension). We discuss these findings in terms of the importance of considering recollection when studying reading processes during development. Alternative explanations considering the role of WM executive functioning are also considered.

Educational mobility and older adults' working memory updating ability: association and role of resilience.

OBJECTIVE: Previous research revealed that a low childhood socioeconomic status, including low parental education, correlates with impaired executive functioning. However, there is a lack of research on the association of working memory updating (WMU) ability, which is one of the major components of executive functioning, and of resilience with educational mobility. The purpose of the present two studies was to further examine these associations. METHOD: In Study 1, 180, 60-88-year old adults with different levels of educational mobility performed a WMU task. In Study 2, 130, 60-89-year old adults that had experienced different levels of upward educational mobility completed a WMU task and a resilience questionnaire. RESULTS: Study 1 revealed that extent of educational mobility was significantly positively associated with WMU ability. Study 2 revealed significant positive associations among extent of educational mobility, resilience, and WMU task performance. CONCLUSION: The results were discussed in terms of possible causal relations between the variables and implications for interventions that aim to enhance upward educational mobility and cognitive functioning in late adulthood.

Association between adolescents' socioeconomic status and working memory updating functioning: Role of parental educational involvement.

Family socioeconomic status (SES) is positively associated with executive functioning. This study tested whether parental educational involvement mediates this association. Two hundred and sixty, 12-15-year-old adolescents completed working memory updating (WMU) and general intelligence tasks, and questionnaires on SES and parental educational involvement. SES and WMU ability were positively associated; there was no difference between the fathers and mothers for three types of educational involvement. The mothers' behavioural involvement positively mediated the SES-WM updating association, whereas a negative mediation was observed for the mothers' intellectual involvement. The fathers' educational involvement did not play a significant mediating role. These results might inform interventions targeting educational involvement for enhancing the cognitive development of children from low SES families.

The relationship between working memory updating components and reading comprehension.

The objective of this study was to determine the contribution of retrieval and substitution components of working memory updating to reading comprehension. Difficulties in reading comprehension have been related to the inability to update information in working memory. Updating is a complex process comprising various subprocesses, such as retrieving information into the focus of attention and substituting information that is no longer relevant. Various numerical subtasks requiring or not requiring the substitution and retrieval components of working memory updating, as well as reading comprehension and general cognitive measures, were administered to a sample (n = 148) of 4th grade children. Less-skilled comprehenders showed lower accuracy when information retrieval was required. In contrast, substitution was not related to reading comprehension. These findings suggest that reading comprehension difficulties are related to the efficacy of information retrieval during updating in working memory.

The impact of intellectual disability and sport expertise on cognitive and executive functions.

Our aim was to identify the suitability of three assessment tools (i.e., Flanker test, Updating Word Span, and Color Trails Test) for future inclusion in the classification process of elite Paralympic athletes with intellectual disability and to assess the strength of the relation between Executive function (EF) and intelligence. Cognitive and EF assessments were performed on 59 participants, divided into four groups according to their cognitive level (with versus without intellectual disability) and sport expertise (athlete versus novice). Inhibition and working memory update skills were implicated in people with intellectual disability. For set-shifting, a more nuanced picture was observed. Strong associations between EF and intelligence was found in people with intellectual disability. Working memory updating and set-shifting are relevant EF skills to assess in the context of elite sport; however, culture-free alternatives for the Updating Word Span test are needed, and alternatives to the Color Trails Test, less reliant on literacy skills are required.

Response inhibition and memory updating in the count/nocount task: an ERP study.

The present study aimed to separate the neural activities between response inhibition and memory updating processes in the Count/Nocount task. Memory load was manipulated to investigate the memory updating process. Within each trial, participants were asked to count/withhold counting the number of O/X letters in the Count/Nocount task. The participants were asked to silently add 1 if a Count letter was presented in the low load condition, and add 2 in the high load condition. Data from 28 healthy participants showed that: (1) in both high load and low load conditions, the latencies of P2 and N2 components were shorter for the Nocount than Count trials, indicating faster attentional orienting and conflict monitoring processes for the Nocount stimuli (i.e., inhibition processes triggered by the Nocount stimuli against those response execution processes triggered by Count stimuli); (2) more positive frontal P3 amplitudes were evoked for the Nocount relative to the Count stimuli, indicating a more intensive response inhibition process for the Nocount trials; (3) a more positive parietal P3 component was evoked for the low load relative to high load condition, indicating a more intensive working memory updating process for the high load condition. This load effect was absent for the frontal P3 component, suggesting that the frontal P3 might not be associated with the memory updating process. In sum, both the cognitive inhibition process (reflected by the frontal P3 component) and working memory updating process (reflected by the parietal P3 component) appear to be involved in the Count/Nocount task.

Individual differences in children's strategy selection in a computational estimation task with two versus three available strategies.

We investigated how children's strategy selection on different problem types was influenced by whether two or three strategies were available in a computational estimation task. Importantly, we examined the influence of individual differences in working memory updating on these effects. Third and fourth graders (N = 725) were asked to indicate the best strategy for two-digit addition problems (e.g., 47 + 24) without calculating estimates. Homogeneous problems (i.e., both unit digits smaller than 5 or larger than 5) and heterogeneous problems (i.e., one operand's unit digit smaller than 5 and the other's unit digit larger than 5) were included. Children completed selection tasks under two conditions: (a) a three-strategy condition, in which they could choose among the rounding-down strategy (i.e., rounding both operands down), the mixed-rounding strategy (i.e., rounding one operand down and the other operand up), and the rounding-up strategy (i.e., rounding both operands up), and (b) a two-strategy condition, in which they could select between the rounding-down strategy and the rounding-up strategy only. As expected, children chose the best available strategy more often under the three-strategy condition than under the two-strategy condition and more often on homogeneous problems than on heterogeneous problems. Importantly, these effects were moderated by children's updating capacities. That is, children with less efficient updating showed worse selection performance on heterogeneous problems than on homogeneous problems under both conditions. In turn, children with more efficient updating showed comparable performance for both problem types under both conditions. These findings have important implications to further our understanding of underlying processes in children's strategy selection in computational estimation.

Working memory updating training modulates a cascade of event-related potentials depending on task load.

The brain mechanisms of working memory (WM) training in humans remain unclear. Here we examined how WM updating training modulates a cascade of event-related potentials (ERPs) elicited at different processing stages. We hypothesized that WM updating training results to decreases in the early responses reflecting stimulus selection and response preparation, and increases the late slow responses reflecting maintenance of to-be-remembered materials. Healthy adults were randomized to a WM updating group that trained an adaptive dual n-back task (n = 20), and an active control group that played a computer game (n = 20). Both groups performed three 25-min training sessions per week for five weeks. Pretest-posttest comparisons showed that the training group significantly improved their performance as compared to the active controls, but this was limited to the trained task. In line with our hypothesis, P2-N2-P3 complex showed changes from pre- to posttest. In the training group this was observed as decreased load-effect while in the control group there was an opposite pattern at some latencies. Slow waves elicited during the maintenance were decreased in the easy task and increased in the difficult task. Taken together, our findings suggest that the early and late ERPs are differentially affected by training. When task demands are high, training may lead to an improved ability to actively maintain several stimuli in memory, and when they are low, training results in more efficient processing and automatization.

Development of hot and cool executive functions in middle childhood: Three-year growth curves of decision making and working memory updating.

Although middle childhood is an important period for the development of hot and cool executive functions (EFs), longitudinal studies investigating trajectories of childhood EF development are still limited and little is known about predictors for individual developmental trajectories. The current study examined the development of two typical facets of cool and hot EFs over a 3-year period during middle childhood, comparing a younger cohort (6- and 7-year-olds at the first wave [T1]; n = 621) and an older cohort (8- and 9-year-olds at T1; n = 975) of children. "Cool" working memory updating (WM) was assessed using a backward digit span task, and "hot" decision making (DM) was assessed using a child variant of the Iowa Gambling Task. Linear latent growth curve analyses revealed evidence for developmental growth as well as interindividual variance in the initial level and rate of change in both EF facets. Initial level of WM was positively associated with age (both between and within cohorts), socioeconomic status, verbal ability, and processing speed, whereas initial levels of DM were, in addition to a (potentially age-related) cohort effect, exclusively predicted by gender, with boys outperforming girls. None of the variables predicted the rate of change, that is, the developmental trajectories. However, younger children, as compared with older children, had slightly steeper WM growth curves over time, hinting at a leveling off in the development of WM during middle childhood. In sum, these data add important evidence to the understanding of hot and cool EF development during middle childhood.

Are training and transfer effects of working memory updating training modulated by achievement motivation?

Previous studies examining effects of working memory (WM) updating training revealed mixed results. One factor that might modulate training gains, and possibly also transfer of those gains to non-trained cognitive tasks, is achievement motivation. In the present Studies 1 and 2, students with either a high (HAM) or low (LAM) achievement motivation completed a 14-day visuospatial WM updating training program. In Study 2, the students also performed a set of tasks measuring other executive functions and fluid intelligence prior to and after training. In both studies, the HAM students displayed a larger training gain than the LAM students. Study 2 revealed that after training, both groups showed better performance on the near-transfer but not far-transfer tasks. Importantly, the differential training gain was not associated with better post-training performance for the HAM compared to the LAM students on any of the transfer tasks. These results are taken to support a modulatory role of achievement motivation on WM training benefits, but not on transfer of those benefits to other tasks. Possible reasons for the general improvement on the near-transfer tasks and the absence of a modulatory role of achievement motivation on transfer-task performance are discussed.

Impaired working memory updating affects memory for emotional and non-emotional materials the same way: evidence from post-traumatic stress disorder (PTSD).

Due to the limited capacity of working memory (WM), efficient suppression of no longer relevant memory contents (inhibition) and revising the current contents of the memory (updating) are crucial factors in memorizing. However, not every individual is able to do so; among them are post-traumatic stress disorder (PTSD) patients who seem to have trouble forgetting trauma-related materials, making their memory overloaded with irrelevant information. The present study assumes that the inability to forget in PTSD patients is due to the impaired updating function of WM and, therefore, suggests that these individuals have inferior WM function for both emotional and unemotional materials. A sample of 30 male veterans with PTSD and 30 healthy individuals (mean age = 46.62, SD = 5.23) participated in the study completing PTSD Checklist, Digit Span Task, and a computerized n-back task. Results revealed that although PTSD subjects showed a generally inferior WM compared with normal individuals; however, their WM performance for emotional and non-emotional stimuli was not significantly different. Supporting the main hypothesis of the study, the findings suggest that a dysfunctional updating function of WM underlies both forgetting and memorizing which affects memory for both emotional and non-emotional material similarly.

Age-related differences in working memory updating components.

The aim of this study was to investigate possible age-related changes throughout childhood and adolescence in different component processes of working memory updating (WMU): retrieval, transformation, and substitution. A set of numerical WMU tasks was administered to four age groups (8-, 11-, 14-, and 21-year-olds). To isolate the effect of each of the WMU components, participants performed different versions of a task that included different combinations of the WMU components. The results showed an expected overall decrease in response times and an increase in accuracy performance with age. Most important, specific age-related changes in the retrieval component were found, demonstrating that the effect of retrieval on accuracy was larger in children than in adolescents or young adults. These findings indicate that the availability of representations from outside the focus of attention may change with age. Thus, the retrieval component of updating could contribute to the age-related changes observed in the performance of many updating tasks.

The effect of ageing on recollection: the role of the binding updating process.

The aim of this study was to highlight the underlying process responsible for the age-related deficit in recollection. Through two experiments using the Remember-Know-Guess procedure (Gardiner, J. M., & Richardson-Klavehn, A. [2000]. Remembering and knowing. In The Oxford handbook of memory (pp. 229-244). New York, NY: Oxford University Press) in recognition, we manipulated the opportunity to update bindings between target items and their encoding context, in young and older adults. In the first experiment we impaired the binding updating process during the encoding of items, while in the second we supported this process. The results indicated that the "Remember" responses in the younger group were specifically reduced by the impairment of the binding updating process (Exp. 1), suggesting that this ability is useful for them to encode a specific episode. Conversely, only the "Remember" responses in the older group were improved in accuracy by supporting the binding updating process (Exp. 2), suggesting that their weakness in this ability is the source of their failure to improve the accuracy of their memories. The overall results support the hypothesis that the age-related decline in episodic memory is partly due to a greater vulnerability to interference on bindings, impairing the ability to update content-context bindings as and when events occur.

Individual differences in cognitive control processes and their relationship to emotion regulation.

Cognitive control and emotional control share many similarities, but the specific relationship between these processes is not well understood. This study explored the relationship between three types of cognitive control (working memory updating, response inhibition and set-shifting) and two emotional regulation strategies (expressive suppression and cognitive reappraisal). Corrugator electromyography, behaviour and self-reports of affect were measured as indices of emotion regulation. Results indicate that working memory updating predicted negative affect reduction during reappraisal and during expressive suppression. This study specifically shows that the working memory component of cognitive control is associated with negative affect reduction. Response inhibition and set-shifting were not specifically related to negative affect reduction, but these variables did predict aspects of emotional behaviour and regulation. These results suggest a general role for cognitive control in some aspects of emotion regulation as well as a specific modulatory role for working memory updating in the regulation of negative affect.

Trait worry is associated with difficulties in working memory updating.

The current study investigated the effects of trait worry, a subcomponent of trait anxiety, on the process of updating information in working memory (WM). A leading theory on anxiety and executive functions, attentional control theory (ACT), states that anxiety is not related to WM updating in emotionally neutral situations. Previous research, however, has focused almost exclusively on WM span tasks that primarily emphasised storage, rather than the updating of WM representations. Moreover, few studies have directly examined the effects of trait worry. In this study, 116 subjects performed a WM updating task that required the memorisation of short lists of words and the within-trial removal of some of these items from WM. Results indicated that levels of trait worry were not related to word-span performance, but were related to performance on trials that required subjects to effectively update WM. Moreover, these effects were observed only for trait worry, not for levels of anxious arousal or comorbid levels of dysphoria. These results support the hypothesis that trait worry is related to WM updating performance and thereby extend ACT in new directions.

Modulation of working memory updating: Does long-term memory lexical association matter?

The aim of the present study was to investigate how working memory updating for verbal material is modulated by enduring properties of long-term memory. Two coexisting perspectives that account for the relation between long-term representation and short-term performance were addressed. First, evidence suggests that performance is more closely linked to lexical properties, that is, co-occurrences within the language. Conversely, other evidence suggests that performance is linked more to long-term representations which do not entail lexical/linguistic representations. Our aim was to investigate how these two kinds of long-term memory associations (i.e., lexical or nonlexical) modulate ongoing working memory activity. Therefore, we manipulated (between participants) the strength of the association in letters based on either frequency of co-occurrences (lexical) or contiguity along the sequence of the alphabet (nonlexical). Results showed a cost in working memory updating for strongly lexically associated stimuli only. Our findings advance knowledge of how lexical long-term memory associations between consonants affect working memory updating and, in turn, contribute to the study of factors which impact the updating process across memory systems.

The association between maternal and child posttraumatic stress symptoms among families living in southern Israel: The buffering role of maternal executive functions.

Posttraumatic stress disorder is a prolonged stress and anxiety response that occurs after exposure to a traumatic event. Research shows that both parental and child posttraumatic stress symptoms (PTSS) are correlated but parental executive functions (EFs) could buffer this link. EFs refers to a group of high-level cognitive processes that enable self-regulation of thoughts and actions to achieve goal-directed behaviours and can be of importance for both positive parenting interactions and effective coping skills for PTSS. Our study aimed to (1) examine the link between maternal and child PTSS and the moderating role of varying degrees of exposure to severe security threats context, and (2) to identify the moderating role of maternal EFs in this interaction, among families living in southern Israel. Our sample included 131 mothers in their second pregnancy and their firstborn children. Mothers performed computerised tasks to assess their EFs and they reported on their own and their child's PTSS. Results revealed a positive correlation between maternal PTSS and child PTSS. However, the link between maternal and child PTSS was moderated by maternal working memory updating abilities and threat context severity. Among mothers with lower updating capacities, the association between maternal and child symptoms was stronger under higher threat contexts; conversely, among mothers with higher maternal updating abilities, threat context did not modulate the link between maternal and child PTSS, suggesting a stress-buffering effect. Our study contributes to the growing literature on the significant role of parental EFs in the context of parent-child interactions.