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

% overall Estimation Error
25
20
15
10
Italian children
Austrian children
Small
Large
A
Figure 5: The mean estimation
error in percent for Italian- and
German-speaking children separated
for items with a small and large
interdigit distance is depicted in
Panel A. The relative under-/overestimation
of specific numbers as
possibly caused by confusing tens
and units is given in Panel B, again
separated for the two langusge
groups. Error bars indicate 1 SEM.
Interdigit Distance
% Relative Estimation Error
8
6
4
2
0
-2
-4
Italian Children
Austrian Children
B
-6
Underestimation
provoked
e.g., 82 --> 28
Overestimation
provoked
e.g., 27 --> 72
DISCUSSION
This study set out to examine the role of language in the development of the mental
number-line in children. Indeed, we observed two major differences between Italian- and
German-speaking first graders. First, the Italian children showed a reliably more accurate
estimation performance than the Austrian children despite somewhat lower general cognitive
abilities in our sample. Second, on the 0-to-100 scale estimation performance was determined
significantly by interdigit distance for German- but not for Italian-speaking children: when
processing the inversion property of German number words incorrectly lead to a number
deviating largely from the correct number (e.g., 72 instead of the correct 27) number-line
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