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

Section 2: On task general influences of the place-value structure of the Arabic number
system in human number representation
1. Study 1: Internal number magnitude representation is not holistic, either.
Regarding the way in which two-digit number magnitude is represented there is
still an ongoing controversy among researchers. After the unit-decade compatibility
effect (indicating decomposed processing of tens and units) has been published it was
criticised to be just a perceptual artefact of the column-wise presentation of the two tobe-compared
numbers one below the other. By replicating the compatibility effect
with different display layouts (Nuerk et al, 2004) as well as for German number words
(Nuerk et al., 2005) these notion could be refuted. Nevertheless, in 2005 Zhang and
Wang presented evidence suggesting that decomposed processing of tens and units
may depend on the presentational format employed (see also Zhou et al., 2008; Ganor-
Stern et al., 2009). The authors found evidence for separate processing of tens and
units when the standard to which a given probe number had to be compared and the
probe itself were externally displayed at the same time. On the other hand, they did not
observe any indication of decomposed processing when the probe had to be compared
to an internally memorized standard. In the current study possible reasons why
decomposed processing of tens and units may not have been detected in previous
studies using a fixed internal standard are outlined. Additionally, an experiment is
presented in which most of these confounds were controlled for.
2. Study 2: On the cognitive instantiation of the carry effect – Evidence from eyetracking.
Previously, the carry effect in addition was assumed to reflect the execution of
asemantic procedural rules rather than involving specific magnitude processing. Such
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