Ansari, D. Effects of development and enculturation on number representation in the brain. Nature Rev. Neurosci. 9, 278-291

Numerical Cognition Laboratory, Department of Psychology and Graduate Program in Neuroscience, University of Western Ontario, Ontario N6G 2K3, Canada.
Nature Reviews Neuroscience (Impact Factor: 31.43). 05/2008; 9(4):278-91. DOI: 10.1038/nrn2334
Source: PubMed


A striking way in which humans differ from non-human primates is in their ability to represent numerical quantity using abstract symbols and to use these 'mental tools' to perform skills such as exact calculations. How do functional brain circuits for the symbolic representation of numerical magnitude emerge? Do neural representations of numerical magnitude change as a function of development and the learning of mental arithmetic? Current theories suggest that cultural number symbols acquire their meaning by being mapped onto non-symbolic representations of numerical magnitude. This Review provides an evaluation of this contention and proposes hypotheses to guide investigations into the neural mechanisms that constrain the acquisition of cultural representations of numerical magnitude.

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    • "Yet no studies to date have systematically investigated whether basic number sense might be a particular strength in children with autism spectrum disorders (ASD). Non-symbolic number sense—the ability to rapidly apprehend approximate quantities—is an evolutionarily conserved capacity (Cantlon and Brannon 2007; Dehaene et al. 1998), while symbolic number sense refers to the uniquely human ability to automatically access quantity information from numerical symbols (Ansari 2008; Dehaene 2011). Emerging research in typically developing (TD) children has suggested that both forms of number sense are predictive of formal mathematics achievement (De Smedt et al. 2013). "
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    • "The distance and size effects are considered to be signatures of the approximate number system (ANS), which is a mental system of approximate magnitude representation that is universal, and is evident very early in life. This system performs non-precise quantity estimation when numerical processing is conducted with nonsymbolic as well as with symbolic stimuli (e.g., Feigenson, Dehaene & Spelke, 2004; Ansari, 2008). Although the issue of the source of the distance effect in symbolic stimuli is currently debated (e.g., Lyons, Nuerk, & Ansari, 2015b), we adopt here the more common view arguing that the facts that comparisons of symbolic and nonsymbolic stimuli show the same ratio and size effects and activate the same areas in the parietal lobes (e.g., Fias, Lammertyn, Reynvoet, Dupont & Orban, 2003) suggest that they are processed by the same mechanism (e.g., Cantlon, Platt, & Brannon, 2009). "
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    ABSTRACT: The present study investigated college students' ability to estimate the results of multi-digit multiplication problems and the extent to which this ability improves with practice. Participants judged whether the results of multiplication problems composed of two-digit numbers were larger or smaller than a given reference number. The reference numbers were either close or far from the exact answer. The effects of practice, size, and distance of the reference number from the exact answer were examined using four measures of performance: speed, accuracy, eye movements, and strategy use. The results show that together with enhanced speed and accuracy with practice, participants also changed the pattern of eye movements and the strategies they used. The eye movement analysis showed longer dwell time and more frequent first fixations toward the reference number with practice, suggesting that participants relied more on the reference number to solve the task with practice. The strategy analysis revealed that with practice participants reduced their use of the approximate calculation strategy, which involves multiplying the rounded operands and comparing the product to the reference number, and increased their reliance on the sense of magnitude strategy which does not involve any calculation, but is grounded in the ANS. This was done especially for trials in which the reference number was far from the exact answer, thus exhibiting enhanced adaptivity in strategy choice with practice.
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    • "These findings suggest that the ITG is influenced by activity in other brain regions with increasing task demands. Representations of numerosity in parietal and frontal brain regions are well investigated in both humans and nonhuman primates (Ansari 2008; Nieder and Dehaene 2009; Dastjerdi et al. 2013; Harvey et al. 2013; Vansteensel et al. 2014). White matter pathways connect ventral temporal cortex to these parietal and frontal regions (Yeatman et al. 2013). "
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