A novel executive function battery for preschoolers: Sensitivity to age differences

The present study investigated sensitivity to age differences in a novel executive function (EF) battery for children aged 18 months to 5 years, and whether the pattern of associations among the measures was consistent with a hierarchical model of EF development. Participants (n = 261, aged 18–67 months) were administered a battery of novel tasks designed to assess 3 key EF components (working memory, inhibition, and shifting). The results indicate that the EF tasks were sensitive to age differences and provide partial support for the hierarchical model of EF development.     

A working memory span task for toddlers

This study presents a new working memory measure for toddlers, inspired by the Spin-the-Pots (Hughes & Ensor, 2005), which we modified structuring it as a memory span task. As in the original task, we required toddlers to retrieve objects hidden in little boxes; however, in our Memory Span Spin-the-Pots (MSSP) we used smaller numbers of targets, and we systematically manipulated memory load, covering or not the display, and rotating it or not. Two experiments involved participants between 18 months and three years. In Experiment 1 we examined the effects of covering and rotation on toddlers’ memory. Either covering or rotating the stimuli hindered their performance, and combining both transformations yielded an under-additive interaction. Moreover, the effect of covering decreased in the second half of the procedure. In Experiment 2 we validated the MSSP as a working memory measure by comparing it with the Imitation Sorting Task (IST; Alp, 1994). We found that the MSSP correlated with the IST, also with age partialled out, although the IST was easier. In both experiments, the scores increased with age. Overall, this research sheds light on some variables that affect toddlers’ performance on the MSSP, and shows that it can be used as a valid working memory measure for toddlers. The results are discussed considering the attentional processes presumably involved.     

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.     

Recall cues interfere with retrieval from visuospatial working memory

Visuospatial working memory allows us to hold multiple visual objects over short delays. It is typically tested by presenting an array of objects, then after a delay showing a ‘probe’ indicating which memory item to recall or reproduce by adjusting a target feature. However, recent studies demonstrate that information at the time of probe can disrupt recall. Here, in three experiments we test whether traditional memory probes, which contain features that compete with the feature to be recalled, may themselves interfere with performance. We asked participants to report the direction of one of the several coloured arrows in memory, based on its colour. First, we demonstrate that recall is better when the probe is initially just a coloured dot, rather than a coloured arrow which has to be adjusted to match orientation memory, consistent with interference from features of the probe itself. Second, this interference is present even when a mask follows the memory array, suggesting that the interference does not work by degrading immediate or iconic memory. Finally, when items are shown sequentially, the first and last items are invulnerable to probe interference. Our findings support recent theories of associative recall, in which probes reactivate features in WM, retrieving information by pattern completion.     

Gender differences in episodic memory and visual working memory including the effects of age

Analysing the relationship between gender and memory, and examining the effects of age on the overall memory-related functioning, are the ongoing goals of psychological research. The present study examined gender and age group differences in episodic memory with respect to the type of task. In addition, these subgroup differences were also analysed in visual working memory. A sample of 366 women and 330 men, aged between 16 and 69 years of age, participated in the current study. Results indicate that women outperformed men on auditory memory tasks, whereas male adolescents and older male adults showed higher level performances on visual episodic and visual working memory measures. However, the size of gender-linked effects varied somewhat across age groups. Furthermore, results partly support a declining performance on episodic memory and visual working memory measures with increasing age. Although age-related losses in episodic memory could not be explained by a decreasing verbal and visuospatial ability with age, women's advantage in auditory episodic memory could be explained by their advantage in verbal ability. Men's higher level visual episodic memory performance was found to result from their advantage in visuospatial ability. Finally, possible methodological, biological, and cognitive explanations for the current findings are discussed.     

The Swedish Hayling task,and its relation to working memory,verbal ability,and speech‐recognition‐in‐noise

Cognitive functions and speech‐recognition‐in‐noise were evaluated with a cognitive test battery, assessing response inhibition using the Hayling task, working memory capacity (WMC) and verbal information processing, and an auditory test of speech recognition. The cognitive tests were performed in silence whereas the speech recognition task was presented in noise. Thirty young normally‐hearing individuals participated in the study. The aim of the study was to investigate one executive function, response inhibition, and whether it is related to individual working memory capacity (WMC), and how speech‐recognition‐in‐noise relates to WMC and inhibitory control. The results showed a significant difference between initiation and response inhibition, suggesting that the Hayling task taps cognitive activity responsible for executive control. Our findings also suggest that high verbal ability was associated with better performance in the Hayling task. We also present findings suggesting that individuals who perform well on tasks involving response inhibition, and WMC, also perform well on a speech‐in‐noise task. Our findings indicate that capacity to resist semantic interference can be used to predict performance on speech‐in‐noise tasks.     

A male advantage for spatial and object but not verbal working memory using the n-back task

Sex-related differences have been reported for performance and neural substrates on some working memory measures that carry a high cognitive load, including the popular n-back neuroimaging paradigm. Despite some evidence of a sex effect on the task, the influence of sex on performance represents a potential confound in neuroimaging research. The present study investigated sex-related differences in verbal, spatial, and common object versions of the high cognitive load "n-back" working memory task. Eighteen male and 18 female undergraduates completed all 3 versions of the task. A mixed ANOVA, with Sex (male and female) as the between-subjects factor and Condition (verbal, spatial, and object) as the within-subjects repeated measure revealed that males were significantly more accurate than females on the spatial and object versions of the n-back task and performed equivalently to females on the verbal version of the task. Although the expected female advantage for verbal working memory was not found using this effortful n-back task, these results support a male advantage for high cognitive load spatial and object working memory. Future research should take into account the influence of sex on performance of the n-back task, and examine sex-related differences in working memory using other paradigms.     

Individual differences in visuospatial working memory: benefits from environmental support for rehearsal

ABSTRACT

Previous research has suggested that participants with low working memory spans are less likely than those with high spans to engage in rehearsal and other effective strategies during memory tasks. However, most of this research has been conducted in the verbal domain, and less is known about strategy differences in visuospatial working memory. Therefore, the present experiments investigated potential individual differences in the benefit participants receive from environmental support for visuospatial rehearsal. In Experiment 1, memory spans were significantly larger when support was present (i.e. when the array of possible locations remained on the screen) during long inter-item intervals, but importantly, the observed benefit was larger for high-span participants than low-span participants, suggesting that high spans were more likely to use support to facilitate their rehearsal. Other research has suggested that low spans may benefit more than high spans from rehearsal instructions, and so in Experiment 2, participants also were provided with such instructions. However, the rehearsal instructions did not improve memory spans significantly in either group, suggesting that low spans are not only naturally less strategic than high spans, but they may be less capable of taking advantage of effective rehearsal strategies, even when environmental support is present.     

A computational model of frontal lobe dysfunction: working memory and the Tower of Hanoi task

A symbolic computer model, employing the perceptual strategy, is presented for solving Tower of Hanoi problems. The model is calibrated—in terms of the number of problems solved, time taken, and number of moves made—to the performance of 20 normal subjects. It is then "lesioned" by increasing the decay rate of elements in working memory to model the performance of 20 patients with lesions to the prefrontal cortex. The model captures both the main effects of subject groups (patients and normal controls) performance, and the subject groups (patients and normal controls) by problem difficulty interactions. This leads us to support the working memory hypothesis of frontal lobe functions, but for a narrow range of problems.     

Attention is required for maintenance of feature binding in visual working memory

Working memory and attention are intimately connected. However, understanding the relationship between the two is challenging. Currently, there is an important controversy about whether objects in working memory are maintained automatically or require resources that are also deployed for visual or auditory attention. Here we investigated the effects of loading attention resources on precision of visual working memory, specifically on correct maintenance of feature-bound objects, using a dual-task paradigm. Participants were presented with a memory array and were asked to remember either direction of motion of random dot kinematograms of different colour, or orientation of coloured bars. During the maintenance period, they performed a secondary visual or auditory task, with varying levels of load. Following a retention period, they adjusted a coloured probe to match either the motion direction or orientation of stimuli with the same colour in the memory array. This allowed us to examine the effects of an attention-demanding task performed during maintenance on precision of recall on the concurrent working memory task. Systematic increase in attention load during maintenance resulted in a significant decrease in overall working memory performance. Changes in overall performance were specifically accompanied by an increase in feature misbinding errors: erroneous reporting of nontarget motion or orientation. Thus in trials where attention resources were taxed, participants were more likely to respond with nontarget values rather than simply making random responses. Our findings suggest that resources used during attention-demanding visual or auditory tasks also contribute to maintaining feature-bound representations in visual working memory—but not necessarily other aspects of working memory.     

Benefits from retrieval practice are greater for students with lower working memory capacity

We examined the effects of retrieval practice for students who varied in working memory capacity as a function of the lag between study of material and its initial test, whether or not feedback was given after the test, and the retention interval of the final test. We sought to determine whether a blend of these conditions exists that maximises benefits from retrieval practice for lower and higher working memory capacity students. College students learned general knowledge facts and then restudied the facts or were tested on them (with or without feedback) at lags of 0–9 intervening items. Final cued recall performance was better for tested items than for restudied items after both 10 minutes and 2 days, particularly for longer study–test lags. Furthermore, on the 2-day delayed test the benefits from retrieval practice with feedback were significantly greater for students with lower working memory capacity than for students with higher working memory capacity (r?=??.42). Retrieval practice may be an especially effective learning strategy for lower ability students.     

Olfactory working memory: exploring the differences in n-back memory for high and low verbalisable odorants

ABSTRACT

We describe four experiments each examining n-back performance for high and low verbalisable odorants. Participants were presented with a sequence of odorants and were required to state if the current odorant was the same or different to the odorant presented two items earlier. Experiment 1 reported superior performance for high, relative to low, verbalisable odorants and was evident despite above-chance memory performance for the low verbalisable odorants. Experiment 2 showed that such superiority persisted with a concurrent articulation condition, suggesting that the memory benefit was not a consequence of verbal recording and rehearsal. Experiment 3 employed metacognitive judgments and showed that correct 2-back responses for high verbalisable odorants received more recollection responses compared to low verbalisable odorants. Experiment 4 compared n-back performance across different stimulus types and showed that, for high verbalisable odorants, performance correlated with both letters and abstract shapes, but such correlations were absent for low verbalisable odorants. Taken together, these findings show differences in n-back performance between high and low verbalisable odorants, and show that high verbalisable odorants exhibit performance similarities with both verbal and visual stimuli. We further argue that n-back performance for low verbalisable odorants operates differently to that of high verbalisable odorants.     

Motor planning between 4 and 7 years of age: Changes linked to executive functions

In the present study, we adopted the conceptual frameworks of Miyake et al. (2000) (organization of executive functions) and Sergeant (2000) (linking executive function to motor behaviour) to assess developmental changes in executive functions and motor behaviour, using a planning task with a sample of 4–7-years old children. More precisely, the aim of the study was to characterize the development of motor response planning between the ages of 4 and 7 as a measure of the integration of multiple executive function processes, namely inhibition, shifting and working memory, and to gain insight into the concurrent developmental contributions of these processes. Participants were divided into two groups: group 1 was composed of 24 children aged 4–5 years and group 2 was composed of 20 children aged 6–7 years. Each participant took tests for shifting, inhibition, working memory and motor planning (the egg-planning task). Our results suggest that the egg-planning task requires the inhibition of a pre-potent but inappropriate response, and to a lesser extent the manipulation of working memory strategies. These results are discussed in relation to the development of each executive function component.     

A secondary task is not always costly: Context‐based guidance of visual search survives interference from a demanding working memory task

Repeatedly encountering a visual search display with the target located at a fixed position relative to the distractors facilitates target detection, relative to novel displays – which is attributed to search guidance by (acquired) long‐term memory (LTM) of the distractor ‘context’ of the target. Previous research has shown that this ‘contextual cueing’ effect is severely impeded during learning when participants have to perform a demanding spatial working memory (WM) task concurrently with the search task, though it does become manifest when the WM task is removed. This has led to the proposal that search guidance by LT context memories critically depends on spatial WM to become ‘expressed’ in behaviour. On this background, this study, of two experiments, asked: (1) Would contextual cueing eventually emerge under dual‐task learning conditions if the practice on the task(s) is extended beyond the short training implemented in previous studies? and given sufficient practice, (2) Would performing the search under dual‐task conditions actually lead to an increased cueing effect compared to performing the visual search task alone? The answer is affirmative to both questions. In particular, Experiment 1 showed that a robust contextual cueing effect emerges within 360–720 dual‐task trials as compared to some 240 single‐task trials. Further, Experiment 2 showed that when dual‐ and single‐task conditions are performed in alternating trials blocks, the cueing effect for the very same set of repeated displays is significantly larger in dual‐task blocks than in single‐task blocks. This pattern of effects suggests that dual‐task practice eventually leads to direct, or ‘automatic’, guidance of visual search by learnt spatial LTM representations, bypassing WM processes. These processes are normally engaged in single‐task performance might actually interfere with direct LTM‐based search guidance.     

The role of the episodic buffer in working memory for language processing

A body of work has accumulated to show that the cognitive process of binding information from different mnemonic and sensory sources as well as in different linguistic modalities can be fractionated from general executive functions in working memory both functionally and neurally. This process has been defined in terms of the episodic buffer (Baddeley in Trends Cogn Sci 4(11):417–423, 2000). This paper considers behavioural, neuropsychological and neuroimaging data that elucidate the role of the episodic buffer in language processing. We argue that the episodic buffer seems to be truly multimodal in function and that while formation of unitary multidimensional representations in the episodic buffer seems to engage posterior neural networks, maintenance of such representations is supported by frontal networks. Although, the episodic buffer is not necessarily supported by executive processes and seems to be supported by different neural networks, it may operate in tandem with the central executive during effortful language processing. There is also evidence to suggest engagement of the phonological loop during buffer processing. The hippocampus seems to play a role in formation but not maintenance of representations in the episodic buffer of working memory.     

Trial distinctiveness in visuospatial working memory: effects on individual differences

ABSTRACT

Previous research has shown that proactive interference (PI) negatively affects performance on working memory (WM) tasks, particularly when to-be-remembered items are similar across trials, and that individuals with low WM spans are more susceptible to PI than those with high spans. The two experiments of the present study further explored individual differences in susceptibility to PI in the visuospatial domain. The similarity of the to-be-remembered locations was manipulated across trials by varying whether locations were presented in different colours and/or accompanied by unique sounds. It was hypothesised that these manipulations would reduce PI, improving participants’ memory. In addition, because of their increased susceptibility to PI, it also was hypothesised that low spans would benefit more than high spans from increases in distinctiveness. The results of both experiments were consistent with these hypotheses, suggesting that even low-span individuals can overcome the effects of PI, given the right task support.     

Effects of age and type of picture on visuospatial working memory assessed with a computerized jigsaw-puzzle task

We investigated the effect of age and color in a computerized version of the jigsaw-puzzle task. In Experiment 1, young and older adults were presented with puzzles in color and black-and-white line drawings, varying in difficulty from 4 to 9 pieces. Older adults performed the task better with the black-and-white stimuli and younger adults performed better with the color ones. In Experiment 2, new older and young adults identified the same fragmented pictures as fast and accurately as possible. The older group identified the black-and-white stimuli faster than those presented in color, while the younger adults identified both similarly. In Experiment 3A, new older and young groups performed the puzzle task with the same color pictures and their monochrome versions. In Experiment 3B, participants performed a speeded identification task with the two sets. The findings of these experiments showed that older adults have a memory not a perceptual difficulty.     

工作记忆中的积极效应：情绪效价与任务相关性的影响

积极效应指相比于年轻人, 老年人更倾向于优先加工积极情绪刺激而非消极情绪刺激。近年来工作记忆的研究发现积极效应会受到情绪效价与任务相关性的影响：情绪效价作为任务相关属性的研究支持工作记忆中存在积极效应, 具体表现为老年人对积极情绪刺激记忆的增强, 以及对消极情绪刺激记忆的减弱; 情绪效价作为工作记忆任务无关属性的研究相对较少, 且未发现一致的积极效应, 提示情绪效价及任务相关性均为影响工作记忆积极效应的关键因素。脑成像的研究初步表明, 工作记忆中情绪加工上的年龄效应与背侧执行系统和腹侧情绪系统的随龄功能变化有关。社会情绪选择理论与双竞争模型对工作记忆中的积极效应具备较大的解释力, 而动态整合理论尚缺乏实证研究支持。未来研究可进一步探究老年人工作记忆不同阶段情绪加工的特点, 澄清不同情绪材料内在编码过程上的差异对积极效应发生机制的潜在影响, 探讨情绪效价及任务相关性影响工作记忆积极效应的关键神经环路, 并揭示情绪工作记忆训练提升老年人认知功能与情绪体验的内在机制及其潜在应用价值。