The Hebb repetition effect in complex span tasks: Evidence for a shared learning mechanism with simple span tasks

The Hebb repetition effect on serial-recall task refers to the improvement in the accuracy of recall of a repeated list (e.g., repeated in every 3 trials) over random non-repeated lists. Previous research has shown that both temporal position and neighboring items need to be the same on each repetition list for the Hebb repetition effect to occur, suggesting chunking as one of its underlying mechanisms. Accordingly, one can expect absence of the Hebb repetition effect in a complex span task, given that the sequence is interrupted by distractors. Nevertheless, one study by Oberauer, Jones, and Lewandowsky (2015, Memory & Cognition, 43[6], 852–865) showed evidence of the Hebb repetition effect in a complex span task. Throughout four experiments, we confirmed the Hebb repetition effect in complex span tasks, even when we included distractors in both encoding and recall phases to avoid any resemblance to a simple span task and minimized the possibility of chunking. Results showed that the Hebb repetition effect was not affected by the distractors during encoding and recall. A transfer cycle analysis showed that the long-term knowledge acquired in the complex span task can be transferred to a simple span task. These findings provide the first insights on the mechanism behind the Hebb repetition effect in complex span tasks; it is at least partially based on the same mechanism that improves recall performance by repetition in simple span tasks.

Reactivated visual masks do not disrupt serial recall. A failed Replication of Rey et al. 2018.

The process of spontaneous refreshing plays a central role in current models of working memory but is yet to be observed directly. In a recent study, Rey and colleagues (Rey, Versace, & Plancher, 2018) introduced a novel approach to investigate the mechanisms underlying refreshing: They presented tones previously associated with a visual mask during the free time of a complex span task, and found that this impaired memory, presumably because reactivation of the masks disrupts refreshing. Here we aimed to replicate their finding under more controlled settings with more observations per participant. We failed to replicate the previous findings, thereby questioning the robustness of the original effect.

Reactivated Visual Masks Do Not Disrupt Serial Recall

The process of spontaneous refreshing plays a central role in current models of working memory but is yet to be observed directly. In a recent study, Rey, Versace, and Plancher (2018) introduced a novel approach to investigate the mechanisms underlying refreshing: They presented tones previously associated with a visual mask during the free time of a complex span task and found that this impaired memory, presumably because reactivation of the masks disrupts refreshing. Here, we aimed to replicate their finding under more controlled settings with more observations per participant. We failed to replicate the previous findings, thereby questioning the robustness of the original effect.

Syntax and working memory in typically-developing children

A growing trend in developmental psycholinguistics is to relate linguistic development to the development of other cognitive systems. Jakubowicz (2005, 2011) in particular argued that the processing of a complex sentence requires considerable working memory (WM) resources and that these resources are limited in young children, which would explain their non-adult grammar. The present research aims to clarify the relationship between WM and complex syntax, in comprehension, repetition, and spontaneous production, in 48 typically-developing children aged 5 to 12. Our results demonstrate a strong age effect for all measures of WM and syntax. They also reveal strong correlations between scores on simple and complex spans and syntactic performance. Finally, we show the highly predictive value of WM capacities on the acquisition of syntactic skills in both comprehension and production. In particular, the complex-span task, measuring counting span, explains the largest part of the variance in the spontaneous production of embedded clauses.

Are working memory training effects paradigm-specific?

A randomized controlled trial compared complex span and n-back training regimes to investigate the generality of training benefits across materials and paradigms. The memory items and training intensities were equated across programs, providing the first like-with-like comparison of transfer in these two widely-used training paradigms. The stimuli in transfer tests of verbal and visuo-spatial n-back and complex span differed from the trained tasks, but were matched across the untrained paradigms. Pre-to-post changes were observed for untrained n-back tasks following n-back training. Following complex span training there was equivocal evidence for improvements on a verbal complex span task, but no evidence for changes on an untrained visuo-spatial complex span activity. Relative to a no intervention group, the evidence supported no change on an untrained verbal complex span task following either n-back or complex span training. Equivocal evidence was found for improvements on visuo-spatial complex span and verbal and visuo-spatial n-back tasks following both training regimes. Evidence for selective transfer (comparing the two active training groups) was only found for an untrained visuo-spatial n-back task following n-back training. There was no evidence for cross-paradigm transfer. Thus transfer is constrained by working memory paradigm and the nature of individual processes executed within complex span tasks. However, within-paradigm transfer can occur when the change is limited to stimulus category, at least for n-back.

When a Reactivated Visual Mask Disrupts Serial Recall

To prevent forgetting in working memory, the attentional refreshing is supposed to increase the level of activation of memory traces by focusing attention. However, the involvement of memory traces reactivation in refreshing relies in the majority on indirect evidence. The aim of this study was to show that refreshing relies on the reactivation of memory traces by investigating how the reactivation of an irrelevant trace prevents the attentional refreshing to take place, and (2) the memory traces reactivated are sensorial in nature. We used a reactivated visual mask presented during the encoding (Experiment 1) and the refreshing (Experiment 2) of pictures in a complex span task. Results showed impaired serial recall performance in both experiments when the mask was reactivated compared to a control stimulus. Experiment 3 confirmed the refreshing account of these results. We proposed that refreshing relies on the reactivation of sensory memory traces.

Measuring the development of working memory capacity: Example of an adaptive complex span task

The aim of this current article is to provide a reflection on how to estimate working memory capacity (WMC), and to investigate its developmental trajectory from eight to twenty-three years-old with a single adaptive and multimodal task. WMC is defined as both storage and manipulation of the information during a cognitive activity. This cognitive aptitude is crucial for the learning and play an important role in the intellectual functioning. WMC is strongly related to some cognitives activities such as the language comprehension, the problems solving or the mathematics. The assessment of WMC therefore seems to be essential throughout lifespan. Although WMC is domain-general, most assessments WMC are based on verbal tasks only. Furthermore, WMC measurement in the developmental studies is limited by the need to preserve discriminating power at all possible ages. The use of a short and composite complex span task adapting itself to the individual’s performance seems meet both requirements. Thus, we created a computerized task that is both multimodal (with verbal and nonverbal subtests) and adaptive to the individual’s abilities: the Adaptive Composite Complex Span (ACCES). With a sample of 724 participants aged between 8 and 23 years-old, our findings show ACCES retains high discriminating power at all chronological ages with no ceiling effect or floor effect. Theoretical and clinical implication are discussed.

The Digit Span Backwards Task

The “digit span backwards” (DSB) is the most commonly used test in clinical neuropsychology to assess working memory capacity. Yet, it remains unclear how the task is solved cognitively. The present study was conducted to examine the use of visual and verbal cognitive strategies in the DSB. Further, the relationship between the DSB and a complex span task, based on the Simultaneous Storage and Processing task ( Oberauer et al., 2003 ), was investigated. Visualizers performed better than verbalizers in the dual task condition (rPB = .23) only when the relevant digits were presented optically. Performance in the DSB correlated only weakly with the complex span task in all conditions (all τ ≤ .21). The results indicate that the processing modality is determined by the preference for a cognitive strategy rather than the presentation modality and suggest that the DSB measures different working aspects than commonly used experimental working memory tasks.