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

verbal recoding of tens and units does not interfere with the order of tens and units in
symbolic notation executing the required unit-decade integrations due to carrying the decade
digit of the unit sum might be less time consuming and/or less susceptible to errors. So, it is
up to future studies to investigate whether differences in place-value coding between different
number word systems has consequences going even beyond the effects reported in this thesis.
Against the background of the accumulating evidence for the importance of place-value
representations such effects should be observable – at least in children whose processing of
numerical (including place-value) information is less automated.
With respect to individual differences, the results of Study 4 indicate that there are
indeed differences in the capability to process place-value information. Also, such differences
in early place-value understanding are predictive not only for later arithmetic performance in
general but also for place-value related aspects of later arithmetic, in particular. Please note
that this is the first time that the longitudinal influence of children’s early place-value
understanding was investigated. The current data suggest that individual differences in placevalue
mastery exist and seem to be relatively stable over time – thereby, implying an
important but so far largely under-investigated role of place-value understanding in numerical
development.
Taken together, Studies 3 and 4 of the current thesis provided evidence for both
individual and cultural differences regarding the mastery of the place-value structure of the
Arabic number system. This is important for at least two reasons: First, it strongly argues for
place-value understanding to be considered a specific numerical representation of its own,
rather than being implicitly subsumed in the representation of number magnitude. Second, it
raises the question whether these observed individual / cultural differences may be of
diagnostic and / or predictive value in the way comparable differences for other numerical
representation have already been employed (see e.g., Delazer et al., 2006; Holloway &
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