scholarly journals Under-resourced or overloaded? Rethinking working memory deficits in developmental language disorder

2021 ◽  
Author(s):  
Samuel David Jones ◽  
Gert Westermann
Keyword(s):  
Working Memory ◽  
Language Disorder ◽  
Spoken Word Recognition ◽  
Working Memory Capacity ◽  
Memory Capacity ◽  
Spoken Word ◽  
Developmental Language Disorder ◽  
Capacity Limitations ◽  
Speech Representation ◽  
Internal Speech

Dominant theoretical accounts of developmental language disorder (DLD) are unanimous in assuming working memory capacity limitations. In the current report, we present an alternative view: That working memory in DLD is not under-resourced but overloaded due to operating on speech representations with low discriminability. This account is developed through computational simulations involving deep convolutional neural networks trained on spoken word spectrograms in which frequency information is either retained to mimic typical development or degraded to mimic spectral processing deficits identified among children with DLD. We assess not only spoken word recognition accuracy and predictive probability and entropy (i.e., predictive distribution spread), but also use mean-field-theory based manifold analysis to assess; (i) internal speech representation dimensionality, and (ii) classification capacity, a measure of networks’ ability to isolate any given internal speech representation that is used as a proxy for attentional control. We show that instantiating a low-level frequency discrimination deficit results in the formation of internal speech representations with atypically high dimensionality, and that classification capacity is exhausted due to low representation separability. These representation and control deficits underpin not only lower performance accuracy but also greater uncertainty even when making accurate predictions in a simulated spoken word recognition task (i.e., predictive distributions with low maximum probability and high entropy), which replicates the response delays and word finding difficulties often seen in DLD. Overall, these simulations demonstrate an integrated theoretical account of speech representation and processing in DLD in which working memory capacity limitations play no causal role.

scholarly journals Lower verbalizability of visual stimuli modulates differences in estimates of working memory capacity between children with and without developmental language disorders

2020 ◽  
Vol 5 ◽  
pp. 239694152094551
Author(s):  
Seçkin Arslan ◽  
Lucie Broc ◽  
Fabien Mathy
Keyword(s):  
Working Memory ◽  
Visual Memory ◽  
Language Disorder ◽  
Working Memory Capacity ◽  
Visual Stimuli ◽  
Memory Capacity ◽  
Typically Developing ◽  
Developmental Language Disorder ◽  
Typically Developing Children ◽  
Short Term

Background and aims Children with developmental language disorder (DLD) often perform below their typically developing peers on verbal memory tasks. However, the picture is less clear on visual memory tasks. Research has generally shown that visual memory can be facilitated by verbal representations, but few studies have been conducted using visual materials that are not easy to verbalize. Therefore, we attempted to construct non-verbalizable stimuli to investigate the impact of working memory capacity. Method and results We manipulated verbalizability in visual span tasks and tested whether minimizing verbalizability could help reduce visual recall performance differences across children with and without developmental language disorder. Visuals that could be easily verbalized or not were selected based on a pretest with non-developmental language disorder young adults. We tested groups of children with developmental language disorder (N = 23) and their typically developing peers (N = 65) using these high and low verbalizable classes of visual stimuli. The memory span of the children with developmental language disorder varied across the different stimulus conditions, but critically, although their storage capacity for visual information was virtually unimpaired, the children with developmental language disorder still had difficulty in recalling verbalizable images with simple drawings. Also, recalling complex (galaxy) images with low verbalizability proved difficult in both groups of children. An item-based analysis on correctly recalled items showed that higher levels of verbalizability enhanced visual recall in the typically developing children to a greater extent than the children with developmental language disorder. Conclusions and clinical implication: We suggest that visual short-term memory in typically developing children might be mediated with verbal encoding to a larger extent than in children with developmental language disorder, thus leading to poorer performance on visual capacity tasks. Our findings cast doubts on the idea that short-term storage impairments are limited to the verbal domain, but they also challenge the idea that visual tasks are essentially visual. Therefore, our findings suggest to clinicians working with children experiencing developmental language difficulties that visual memory deficits may not necessarily be due to reduced non-verbal skills but may be due to the high amount of verbal cues in visual stimuli, from which they do not benefit in comparison to their peers.

scholarly journals Differences in Working Memory Capacity Affect Online Spoken Word Recognition: Evidence From Eye Movements

2019 ◽  
Vol 23 ◽  
pp. 233121651983962 ◽  
Author(s):  
Gal Nitsan ◽  
Arthur Wingfield ◽  
Limor Lavie ◽  
Boaz M Ben-David
Keyword(s):  
Working Memory ◽  
Word Recognition ◽  
Time Course ◽  
Memory Span ◽  
Spoken Word Recognition ◽  
Working Memory Capacity ◽  
Memory Capacity ◽  
Spoken Word ◽  
High Load ◽  
Low Load

Individual differences in working memory capacity have been gaining recognition as playing an important role in speech comprehension, especially in noisy environments. Using the visual world eye-tracking paradigm, a recent study by Hadar and coworkers found that online spoken word recognition was slowed when listeners were required to retain in memory a list of four spoken digits (high load) compared with only one (low load). In the current study, we recognized that the influence of a digit preload might be greater for individuals who have a more limited memory span. We compared participants with higher and lower memory spans on the time course for spoken word recognition by testing eye-fixations on a named object, relative to fixations on an object whose name shared phonology with the named object. Results show that when a low load was imposed, differences in memory span had no effect on the time course of preferential fixations. However, with a high load, listeners with lower span were delayed by ∼550 ms in discriminating target from sound-sharing competitors, relative to higher span listeners. This follows an assumption that the interference effect of a memory preload is not a fixed value, but rather, its effect is greater for individuals with a smaller memory span. Interestingly, span differences affected the timeline for spoken word recognition in noise, but not offline accuracy. This highlights the significance of using eye-tracking as a measure for online speech processing. Results further emphasize the importance of considering differences in cognitive capacity, even when testing normal hearing young adults.

Children's long‐term retention is directly constrained by their working memory capacity limitations

2021 ◽  
Author(s):  
Alicia Forsberg ◽  
Dominic Guitard ◽  
Eryn J. Adams ◽  
Duangporn Pattanakul ◽  
Nelson Cowan
Keyword(s):  
Working Memory ◽  
Working Memory Capacity ◽  
Memory Capacity ◽  
Capacity Limitations ◽  
Term Retention ◽  
Long Term Retention

scholarly journals Comprehension of Welcher -Questions in German-Speaking Children With and Without Developmental Language Disorder

2021 ◽  
pp. 1-13
Author(s):  
Anne Dorothée Roesch ◽  
Vasiliki Chondrogianni
Keyword(s):  
Working Memory ◽  
Language Disorder ◽  
Working Memory Capacity ◽  
Question Type ◽  
Typically Developing ◽  
Developmental Language Disorder ◽  
Typically Developing Children ◽  
Phonological Working Memory ◽  
Case Marking ◽  
German Speaking

Purpose This study examined whether monolingual German-speaking preschool children with developmental language disorder (DLD) were facilitated by the presence of case-marking cues in their interpretation of German subject and object welcher (“which”)-questions, as reported for their typically developing peers. We also examined whether knowledge of case-marking and/or phonological working memory modulated children's ability to revise early assigned interpretations of ambiguous questions. Method Sixty-three monolingual German-speaking children with and without DLD aged between 4;0 and 5;11 (years;months) participated in an offline picture selection task targeting the comprehension of welcher -questions in German. We manipulated question type (subject, object), case-marking transparency, and case-marking position within the question (sentence-initial/-final). Results The typically developing children outperformed the children with DLD across conditions, and all children performed better on subject than on object wh -questions. Transparent and early cues elicited higher accuracy than late-arriving cues. For the DLD children, their working memory capacity explained their inability to revise early assigned interpretations to ambiguous questions, whereas their knowledge of case did not. Conclusions The results suggest that disambiguating morphosyntactic cues can only partly facilitate comprehension of German welcher -questions in children with DLD, whose poor phonological working memory rather than their knowledge of case-marking mediates performance on these structures.

scholarly journals Chunking as a rational strategy for lossy data compression in visual working memory

2017 ◽  
Author(s):  
Matthew R. Nassar ◽  
Julie C. Helmers ◽  
Michael J. Frank
Keyword(s):  
Working Memory ◽  
Visual Working Memory ◽  
Performance Optimization ◽  
Human Performance ◽  
Storage Capacity ◽  
Working Memory Capacity ◽  
Quantitative Description ◽  
Memory Task ◽  
Memory Capacity ◽  
Capacity Limitations

AbstractThe nature of capacity limits for visual working memory has been the subject of an intense debate that has relied on models that assume items are encoded independently. Here we propose that instead, similar features are jointly encoded through a “chunking” process to optimize performance on visual working memory tasks. We show that such chunking can: 1) facilitate performance improvements for abstract capacity-limited systems, 2) be optimized through reinforcement, 3) be implemented by center-surround dynamics, and 4) increase effective storage capacity at the expense of recall precision. Human performance on a variant of a canonical working memory task demonstrated performance advantages, precision detriments, inter-item dependencies, and trial-to-trial behavioral adjustments diagnostic of performance optimization through center-surround chunking. Models incorporating center-surround chunking provided a better quantitative description of human performance in our study as well as in a meta-analytic dataset, and apparent differences in working memory capacity across individuals were attributable to individual differences in the implementation of chunking. Our results reveal a normative rationale for center-surround connectivity in working memory circuitry, call for re-evaluation of memory performance differences that have previously been attributed to differences in capacity, and support a more nuanced view of visual working memory capacity limitations: strategic tradeoff between storage capacity and memory precision through chunking contribute to flexible capacity limitations that include both discrete and continuous aspects.

scholarly journals The origin of the visual working memory capacity limitations

2016 ◽  
Vol 16 (12) ◽  
pp. 1060
Author(s):  
Marjan Persuh ◽  
Emmanuel Delgado ◽  
Aharon Zarzar
Keyword(s):  
Working Memory ◽  
Visual Working Memory ◽  
Working Memory Capacity ◽  
Memory Capacity ◽  
Capacity Limitations
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