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

one even before having seen the second number. Thereby, when the second number is
presented this expectation is either confirmed or disconfirmed. In the first case, no further
processing of the two numbers magnitude is required and only in the latter case additional
evaluations of the magnitude relations between tens and units may be initiated. Thereby, the
results for simultaneous and sequential presentation conditions may stem from two
completely different underlying processes and thus direct comparisons should be treated with
caution.
Moreover, the issue of confirming / disconfirming expectations about the second
number may be even aggravated by the realization of the sequential presentation condition.
From a methodological point of view it seems problematic that to-be-compared numbers were
presented sequentially at exactly the same position and with an inter-number-interval of only
200 ms without using a backward mask. Even when about one-third within-decade trials such
as 43_49 were included to prevent participants from focusing on the tens position only (see
Experiment 2 of Ganor-Stern et al., 2008), at this speed the task is more like a visual
discrimination task on the tens position than a number magnitude comparison task requiring
the processing of both tens and units. Imagine the case of a within-decade trial, with an internumber-interval
of just 200 ms and both numbers being presented at exactly the same position
such an item is identified immediately by a change of the visual input at the unit position
only. On the other hand, between-decade trials can be identified 100 % correct by a change of
visual stimulus properties at the tens position. Thereby, the sequential condition as realized by
Ganor-Stern et al. (2008) includes visual cues coding which digit is relevant for which trial
that are 100 % valid. Based on this methodological flaw synced with above considerations on
possible representational differences between sequential and simultaneous presentation
conditions the claim of a holistic magnitude representation engaged in the sequential
processing condition seems much too strong. A future study preventing visual cues to be 100
% valid by e.g., employing a backward mask presented after each individual number or
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