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The influence of the place-value structure of the Arabic number ...

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However, unlike in previous studies (e.g., Holloway & Ansari, 2009) <strong>the</strong> use <strong>of</strong> two-digit<br />

stimuli allowed for <strong>the</strong> evaluation <strong>of</strong> <strong>place</strong>-<strong>value</strong> processing. In Study 3 <strong>of</strong> <strong>the</strong> current <strong>the</strong>sis it<br />

was observed that <strong>the</strong> worse children’s <strong>place</strong>-<strong>value</strong> understanding was in first grade <strong>the</strong> worse<br />

<strong>the</strong>y performaned in an addition task administered in third grade. Notably, a higher <strong>number</strong> <strong>of</strong><br />

inversion transcoding errors in first grade was associated with a larger <strong>number</strong> <strong>of</strong> errors in<br />

carry addition problems and a larger carry effect in third grade, both indicating impaired<br />

processes <strong>of</strong> <strong>place</strong>-<strong>value</strong> integration. Thus, <strong>the</strong>se data not only suggested a reliable <strong>influence</strong><br />

<strong>of</strong> <strong>place</strong>-<strong>value</strong> understanding on numerical development but also indicated ra<strong>the</strong>r direct<br />

developmental trajectories for <strong>the</strong> representation <strong>of</strong> <strong>the</strong> <strong>place</strong>-<strong>value</strong> <strong>structure</strong> <strong>of</strong> <strong>the</strong> <strong>Arabic</strong><br />

<strong>number</strong> system.<br />

Specificities in processing <strong>place</strong>-<strong>value</strong> information<br />

Fur<strong>the</strong>r indication for <strong>the</strong> validity <strong>of</strong> decomposed processing to be a ra<strong>the</strong>r general<br />

characteristic <strong>of</strong> multi-digit <strong>number</strong> processing comes from modelling results. On <strong>the</strong> one<br />

hand a two-linear model suggesting two separate representations <strong>of</strong> single- and two-digit<br />

<strong>number</strong>s fitted children’s estimation pattern in <strong>the</strong> <strong>number</strong> line task reliably better than did a<br />

holistic logarithmic model (see Moeller, Pixner, Kaufmann, & Nuerk, 2009b; Study 3). On<br />

<strong>the</strong> o<strong>the</strong>r hand, directly contrasting all three proposed models <strong>of</strong> two-digit <strong>number</strong> magnitude<br />

representation (i.e., holistic, strictly decomposed, and hybrid) using computational modelling<br />

revealed that <strong>the</strong> compatibility effect could not be simulated by <strong>the</strong> holistic model but by <strong>the</strong><br />

strictly decomposed and <strong>the</strong> hybrid model. Taking into account model proximity it was found<br />

that all empirical effects observed for symbolic two-digit <strong>number</strong> comparison could be<br />

simulated by a strictly decomposed model. Against this background <strong>the</strong> question arises<br />

whe<strong>the</strong>r <strong>the</strong>re is a specific neural correlate associated with <strong>the</strong> processing <strong>of</strong> <strong>place</strong>-<strong>value</strong><br />

properties. Assessed by <strong>the</strong> <strong>number</strong> bisection task, increased activation in posterior parts <strong>of</strong><br />

<strong>the</strong> IPS was found for <strong>the</strong> evaluation <strong>of</strong> triplets crossing a decade boundary that required<br />

300

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