Impaired large numerosity estimation and intact subitizing in developmental dyscalculia

Gisella Decarli, Emanuela Paris, Chiara Tencati, Chiara Nardelli, Massimo Vescovi, Luca Surian, Manuela Piazza, Jérôme Prado
2020 PLoS ONE  
It is believed that the approximate estimation of large sets and the exact quantification of small sets (subitizing) are supported by two different systems, the Approximate Number System (ANS) and Object Tracking System (OTS), respectively. It is a current matter of debate whether they are both impaired in developmental dyscalculia (DD), a specific learning disability in symbolic number processing and calculation. Here we tackled this question by asking 32 DD children and 32 controls to perform
more » ... controls to perform a series of tasks on visually presented sets, including exact enumeration of small sets as well as comparison of large, uncountable sets. In children with DD, we found poor sensitivity in processing large numerosities, but we failed to find impairments in the exact enumeration of sets within the subitizing range. We also observed deficits in visual short-term memory skills in children with dyscalculia that, however, did not account for their low ANS acuity. Taken together, these results point to a dissociation between quantification skills in dyscalculia, they highlight a link between DD and low ANS acuity and provide support for the notion that DD is a multifaceted disability that covers multiple cognitive skills.
doi:10.1371/journal.pone.0244578 pmid:33382740 fatcat:najo42tij5bhvpko3z3fcgurtm