Impaired large numerosity estimation and intact subitizing in developmental dyscalculia

Decarli, Gisella; Paris, Emanuela; Tencati, Chiara; Nardelli, Chiara; Vescovi, Massimo; Surian, Luca; Piazza, Manuela

doi:10.1371/journal.pone.0244578

Cited by 22 publications

(21 citation statements)

References 81 publications

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“…Two broad hypotheses -numerosity deficit and symbolmagnitude mapping deficit -advocate a domain-specific disorder, whereas the executive function (EF) hypothesis posits domain general issues. The numerosity deficit hypothesis proposed a core deficit in processing quantity (Butterworth et al, 2011) and number sense (Dehaene et al, 2004;Decarli et al, 2020). The symbol-magnitude mapping deficit hypothesis proposed a specific weakness in automatically mapping symbols to their internal magnitude representations (Rubinsten and Henik, 2006;Rousselle and Noel, 2007).…”

Section: The Theoretical Perspective: Historymentioning

confidence: 99%

Mathematics Disability vs. Learning Disability: A 360 Degree Analysis

Nicolson

Fawcett

2021

Front. Psychol.

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A fundamental issue for research in mathematics disability (MD) and reading disability (RD) is: If these disabilities are clearly distinct, why is there so high a level of comorbidity, together with the converse; if these disabilities are so similar, why are there clear differences in underlying causes and aetiology? In order to address this puzzle, we introduce the “360 degree analysis” (360DA) framework and apply it to the overlap between RD and MD. The 360DA process starts by analyzing the issue from four perspectives: theoretical, developmental, affective, and pedagogical. Under 360DA, these analyses are then integrated to provide insights for theory, and for individual assessment and support, together with directions for future progress. The analyses confirm extensive similarities between arithmetic and reading development in terms of rote learning, executive function (EF), and affective trauma, but also major differences in terms of the conceptual needs, the motor coordination needs, and the methods of scaffolding. In terms of theory, commonalities are interpreted naturally in terms of initial general developmental delay followed by domain-independent affective trauma following school failure. Dissociations are interpreted in terms of cerebellar vs. hippocampal learning networks, sequential vs. spatial processing, and language vs. spatial scaffolding, with a further dimension of the need for accurate fixation for reading. The framework has significant theoretical and applied implications.

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Section: The Theoretical Perspective: Historymentioning

confidence: 99%

Mathematics Disability vs. Learning Disability: A 360 Degree Analysis

Nicolson

Fawcett

2021

Front. Psychol.

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“…In contrast, individual variability in subitizing capacity has not been reliably associated with arithmetic skills ( Anobile et al, 2019 ). Moreover, individuals with specific difficulties in mathematics (developmental dyscalculia) show impaired numerosity estimation ( Piazza et al, 2010 ; Mazzocco et al, 2011a ) but intact subitizing capacity ( Decarli et al, 2020 ; but see Schleifer and Landerl, 2011 ). Conversely, impaired subitizing (but not estimation) has been observed in individuals with Down syndrome ( Sella et al, 2013 ), who are also known to suffer from visuospatial working memory deficits.…”

Section: Introductionmentioning

confidence: 99%

Electrophysiological Signatures of Numerosity Encoding in a Delayed Match-to-Sample Task

Dolfi

Decarli

et al. 2022

Front. Hum. Neurosci.

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The number of elements in a small set of items is appraised in a fast and exact manner, a phenomenon called subitizing. In contrast, humans provide imprecise responses when comparing larger numerosities, with decreasing precision as the number of elements increases. Estimation is thought to rely on a dedicated system for the approximate representation of numerosity. While previous behavioral and neuroimaging studies associate subitizing to a domain-general system related to object tracking and identification, the nature of small numerosity processing is still debated. We investigated the neural processing of numerosity across subitizing and estimation ranges by examining electrophysiological activity during the memory retention period in a delayed numerical match-to-sample task. We also assessed potential differences in the neural signature of numerical magnitude in a fully non-symbolic or cross-format comparison. In line with behavioral performance, we observed modulation of parietal-occipital neural activity as a function of numerosity that differed in two ranges, with distinctive neural signatures of small numerosities showing clear similarities with those observed in visuospatial working memory tasks. We also found differences in neural activity related to numerical information in anticipation of single vs. cross-format comparison, suggesting a top-down modulation of numerical processing. Finally, behavioral results revealed enhanced performance in the mixed-format conditions and a significant correlation between task performance and symbolic mathematical skills. Overall, we provide evidence for distinct mechanisms related to small and large numerosity and differences in numerical encoding based on task demands.

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“…The association between subitizing and one’s mathematical abilities on surface seems to imply subitizing is numerical in nature. However, recent studies have also shown that subitizing ability does not necessarily predict one’s math abilities ( Anobile et al, 2019 ), as well as that developmental dyscalculia is not always associated with impairment in subitizing ability ( Decarli et al, 2020 ). As such, theorists have proposed other attentional or pattern recognition mechanisms that are not necessarily numerical in nature to account for findings in subitizing.…”

Section: Introductionmentioning

confidence: 99%

Effect of Non-canonical Spatial Symmetry on Subitizing

Hsin

Tseng³

2021

Front. Psychol.

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Subitizing refers to ability of people to accurately and effortlessly enumerate a small number of items, with a capacity around four elements. Previous research showed that “canonical” organizations, such as familiar layouts on a dice, can readily improve subitizing performance of people. However, almost all canonical shapes found in the world are also highly symmetrical; therefore, it is unclear whether previously reported facilitative effect of canonical organization is really due to canonicality, or simply driven by spatial symmetry. Here, we investigated the possible effect of symmetry on subitizing by using symmetrical, yet non-canonical, shape structures. These symmetrical layouts were compared with highly controlled random patterns (Experiment 1), as well as fully random and canonical patterns (Experiment 2). Our results showed that symmetry facilitates subitizing performance, but only at set size of 6, suggesting that the effect is insufficient to improve performance of people in the lower or upper range. This was also true, although weaker, in reaction time (RT), error distance measures, and Weber Fractions. On the other hand, canonical layouts produced faster and more accurate subitizing performances across multiple set sizes. We conclude that, although previous findings mixed symmetry in their canonical shapes, their findings on shape canonicality cannot be explained by symmetry alone. We also propose that our symmetrical and canonical results are best explained by the “groupitizing” and pattern recognition accounts, respectively.

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Impaired large numerosity estimation and intact subitizing in developmental dyscalculia

Cited by 22 publications

References 81 publications

Mathematics Disability vs. Learning Disability: A 360 Degree Analysis

Mathematics Disability vs. Learning Disability: A 360 Degree Analysis

Electrophysiological Signatures of Numerosity Encoding in a Delayed Match-to-Sample Task

Effect of Non-canonical Spatial Symmetry on Subitizing

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