Electronic Thesis and Dissertation Repository

Degree

Doctor of Philosophy

Program

Psychology

Supervisor

Dr. Daniel Ansari

Abstract

What are the cognitive underpinnings of arithmetic and how do they contribute to individual differences in children’s calculation abilities? Behavioural research has provided insights into which domain general (e.g. working memory) and domain specific (e.g. symbol-quantity associations) competencies are important for the acquisition of arithmetic skills. However, how domain general and domain specific skills are related to arithmetic at the neural level remains unclear. This thesis investigates the interplay between arithmetic and both domain general and specific competencies in the brain.

In Chapter 2 I examine how visuo-spatial working memory (VSWM) networks overlap with those for arithmetic in children and adults. While both children and adults recruited the intraparietal sulcus (IPS) for VSWM and arithmetic, children showed more focal activation within the right IPS, whereas adults recruited the bilateral IPS. These findings indicate that the regions underlying VSWM and arithmetic undergo age-related changes and become more left-lateralized in adults.

Chapter 3 provides evidence that basic number processing networks overlap with those for arithmetic in adults and children. Number processing and arithmetic elicited conjoint activity in the IPS in children and adults. Their overlap was also related to arithmetic problem size (i.e. how demanding the problems were of time-intensive procedural strategies); both arithmetic and basic number processing recruited the IPS when the problems relied on procedural strategies that likely involve the manipulation of numerical quantities.

In Chapter 4 I investigate how individual differences in domain general and domain specific competencies relate to the recruitment of the IPS during arithmetic. Both VSWM and symbolic number skills correlated with brain activity in the IPS, however, the relationships depended on the index of brain activity used. VSWM was related to a neural index of arithmetic complexity (neural problem size effect), whereas symbolic number skills were related to overall arithmetic activity (small and large problems).

The present thesis provides the first empirical evidence that shows how domain general and domain specific abilities are related to the neural basis of arithmetic in children and adults. Moreover, this thesis suggests the IPS plays a multifaceted role during arithmetic and cannot be attributed to one function.


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