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

particular theoretical considerations on the mental representation of number magnitude into
computational neural network models to evaluate differing notions regarding scaling
properties of the mental number line, for instance (e.g., Zorzi & Butterworth, 1999; Dehaene
& Changeaux, 1993; Grossberg & Repin, 2003; Verguts & Fias, 2004; 2008; Verguts, Fias, &
Stevens, 2005). However, there is currently no computational model trying to realize a
decomposed representation of two-digit number magnitude. Actually, most models did not
even aim to account for two-digit number magnitude but were focused on single-digit or, at a
maximum, teen numbers (but see Grossberg & Repin, 2003). Therefore, apart from promoting
the generalizability of the notion of decomposed processing of two-digit numbers, an integral
aim of the current thesis was to provide first computational evidence corroborating recent
empirical results. In this vein, Study 7 pursued this goal by a direct comparison of three
computational model each reflecting one of the current models of number magnitude
representation (i.e., holistic, strictly decomposed, or hybrid, see above) by evaluating in how
far modelled data replicated empirical effects such as the distance and unit-decade
compatibility effect. Thereby, we wished to add a further line of evidence for the validity of
the notion of decomposed processing of two-digit number magnitude the findings from classic
behavioural (Studies 1 and 2), developmental (Studies 3 and 4), and neuro-psychological
(Studies 5 and 6) experiments.
In the following section, the theoretical background and the intention of the studies
pursuing above introduced issues will be discussed briefly to serve as an outline of what will
be investigated why and in which way in each of the individual studies.
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