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

for triplets crossing a decade boundary was more pronounced in neglect patients (+ 18.4 %
errors) than in healthy controls (- 0.8 % errors) but not when compared to patient controls (+
7.5 % errors).
Furthermore, a strong main effect for decade-crossing was found for both speed and
accuracy [RT: F(1, 15) = 40.74, p < .001, accuracy: F(1, 15) = 17.38, p < .001]. So, triplets
that did not cross a decade boundary were responded to faster (4164 ms) and more accurate
(4.4 % errors) than triplets which crossed into the next decade (4702 ms and 12.8 % errors).
Moreover, the ANOVA revealed that the three participant groups differed reliably regarding
errors committed [F(2, 15) = 3.78, p < .05] but not RT [F(2, 15) = 2.76, p = .10]. Bonferroni-
Holm corrected t-tests confirmed the hypothesis that neglect patients did more errors
compared to patient controls [+13.7 %, t(10) = 2.22, p = .05, one-sided] as well as healthy
controls [+13.7 %, t(10) = 1.94, p < .05, one-sided].
Multiplicativity: A main effect for multiplicativity was observed neither for RT nor for
errors [RT: F(1, 15) < 1, errors: F(1, 15) = 1.59, p = .23]. However, neglect patients and nonneglect
controls differed significantly for errors committed [F (2, 15) = 5.27, p < .05] but not
for response latencies [F (2, 15) < 1]. Again, Bonferroni-Holm corrected t-tests showed that
neglect patients’ performance was more error prone compared to that of patient controls
[+16.7 %, t(10) = 2.62, p < .05, one-sided] as well as healthy controls [+14.1 %, t(10) = 2.72,
p < .05, one-sided]. Finally, multiplicativity and participant group did not interact reliably for
either RT or errors [RT: F(2, 15) < 1, errors: F(2, 15) < 1].
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