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

strong influence on numerical development in children (cf. Study 3) and that, regarding
individual differences, sufficient place-value understanding in early years is a building block
for later arithmetical competencies (cf. Study 4).
CONCLUSIONS
All in all, a recapitulated view on the results provided by this thesis reveals a number
of important new insights in the influence of the place-value structure of the Arabic number
system on numerical cognition. (i) Empirical evidence on decomposed processing of multidigit
numbers obtained from different numerical tasks administered to different populations
(i.e., German- and Italian-speaking children, healthy adults, and neglect patients) and assessed
using different experimental methodologies (i.e., reaction time, eye-tracking , and fMRI
paradigms) further corroborates the notion that the place-value structure of the Arabic number
system is retained whenever multi-digit numbers are processed. (ii) Consolidated evaluation
of the results of the individual studies provides converging evidence that place-value
constraints exhibit a task invariant influence on human numerical cognition and its
development. In particular, evidence for the general validity of place-value influences
originates from studies revealing (i) that the mental number line is not analogue holistic in
nature but incorporates place-value information as well (cf. Studies 1, 5, and 6), (ii) that
decomposed processing of two-digit numbers could be observed for new basic numerical as
well as basic arithmetical tasks [i.e., number line estimation (cf. Study 3) and addition (cf.
Study 2), respectively], (iii) that decomposed processing is reliably influenced by a
language’s number word system but seems to develop culture invariant (cf. Study 4), (iv) that
(computational) models realizing and/or reflecting decomposed processing of tens and units
outperformed models of holistic processing when compared directly (cf. Studies 3 and 7), and
(v) that on a neurofunctional level specific neural correlates of processing place-value
information can be identified. Hence, the results of this thesis can be recapitulated as
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