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Probing the nature of deficits in the ‘Approximate Number System’ in children with persistent Developmental Dyscalculia
Author(s) -
Bugden Stephanie,
Ansari Daniel
Publication year - 2016
Publication title -
developmental science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.801
H-Index - 127
eISSN - 1467-7687
pISSN - 1363-755X
DOI - 10.1111/desc.12324
Subject(s) - dyscalculia , psychology , typically developing , developmental psychology , perception , audiology , working memory , cognitive psychology , cognition , dyslexia , neuroscience , autism , medicine , reading (process) , political science , law
In the present study we examined whether children with Developmental Dyscalculia ( DD ) exhibit a deficit in the so‐called ‘Approximate Number System’ ( ANS ). To do so, we examined a group of elementary school children who demonstrated persistent low math achievement over 4 years and compared them to typically developing ( TD ), aged‐matched controls. The integrity of the ANS was measured using the Panamath ( www.panamath.org ) non‐symbolic numerical discrimination test. Children with DD demonstrated imprecise ANS acuity indexed by larger Weber fraction (w) compared to TD controls. Given recent findings showing that non‐symbolic numerical discrimination is affected by visual parameters, we went further and investigated whether children performed differently on trials on which number of dots and their overall area were either congruent or incongruent with each other. This analysis revealed that differences in w were only found between DD and TD children on the incongruent trials. In addition, visuo‐spatial working memory strongly predicts individual differences in ANS acuity (w) during the incongruent trials. Thus the purported ANS deficit in DD can be explained by a difficulty in extracting number from an array of dots when area is anti‐correlated with number. These data highlight the role of visuo‐spatial working memory during the extraction process, and demonstrate that close attention needs to be paid to perceptual processes invoked by tasks thought to represent measures of the ANS .