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

epresented separately also in the internal representation of two-digit numbers as the authors
observed a reliable compatibility effect for comparisons of a given number to an internally
memorized standard (RT for compatible comparisons: 492 ms vs. incompatible comparisons:
504 ms, see Figure 3, Panel A). Furthermore, this compatibility effect was found to be
particularly driven by the compatibility effect for comparisons with a large unit distance (+ 16
ms) while it could not be obtained for comparisons with a small unit distance (+ 8 ms).
Holistic Model
ANCOVA
A regression analysis revealed that modelled RT data accounted for only 10% of the
variance in the empirical RT data [r = .32; F(2, 86) = 9.73, p < .01]. Furthermore, analyzing
the RT estimates produced by the holistic model showed that neither the main effect of
compatibility nor its interaction with unit distance was statistically reliable [all F < 1].
Additionally, separate analyses for comparisons for large and small unit distances revealed
that the compatibility effect was not significant in both analyses [both F < 1] indicating no
modulation of the compatibility effect by unit distance (see Figure 3, Panel B). Nevertheless,
the influence of the covariate problem size was significant in all analyses [two-way ANOVA:
F(1, 39) = 14.53, p < .001; large unit distance: F(1, 9) = 6.22, p < .05; small unit distance:
F(1, 29) = 9.16, p < .01]. Thus, as has been the case for comparisons to a variable standard
(see above) the holistic model could not account for the unit-decade compatibility effect.
Regression
The final regression model for the data produced by the holistic model accounted for a
significant amount of variance [adj. R 2 = .31, R = .59, F(2, 37) = 9.67, p < .001] and included
the predictors absolute problem size and difference between the logarithmic magnitudes of the
two to-be-compared numbers (see Table 4). Evaluation of the beta weights revealed that
260