“Count on me!” : Mathematical development, developmental dyscalculia and computer-based intervention

Sammanfattning: A “sense” of number can be found across species, yet only humans supplement it with exact and symbolic number, such as number words and digits. However, what abilities leads to successful or unsuccessful arithmetic proficiency is still debated. Furthermore, as the predictability between early understanding of math and later achievement is stronger than for other subjects, early deficits can cause significant later deficits. The purpose of the current thesis was to contribute to the description of what aspects of non-symbolic and symbolic processing leads to later successful or unsuccessful arithmetic proficiency, and to study the effects of different designs of computer-programs on pre-school class aged children. The cognitive mechanisms underlying symbolic number processing and different arithmetic skills were mapped to discover their contributions to children’s proficiency. Findings show that the non-symbolic system continues to contribute to arithmetic performance, and that the general cognitive abilities’ contributions might vary with development. Moreover, more advanced mathematical skills were supported by less advanced. In order to investigate the underlying core deficit in DD, performance was contrasted with an individually matched control group on general cognitive abilities. Findings indicate that DD children are impaired on both nonsymbolic and symbolic processing, the most impairment on the symbolic measures. Furthermore, the results indicated subgroups. In order to investigate the effects of early intervention, three theoretically different designs of computer programs, designed in accordance to hypotheses of number processing were compared to a passive control group. Results revealed that even brief, daily arithmetic training utilizing theoretically different designs impacted different aspects of symbolic processing. The presented findings indicate that the non-symbolic system is the foundation for the symbolic system, and that DD is caused by a non-symbolic deficit. The present thesis also adds evidence that formal arithmetic is founded on precise representations, rather than approximate.