Neural Correlates of Processing Syntax in Music and ... - PubMan

Experiment IV 148
tion cross vs. silent movie), and the between-subjects factor subgroup (MT vs. NM) was
used to evaluate these ERP responses. An overview of the results can be found in Table
12-2 (column 3). The ANOVA revealed interactions of syntactic regularity × anteriorposterior
distribution, of syntactic regularity × anterior-posterior distribution × hemisphere,
and of syntactic regularity × hemisphere. These interactions are due to the larger
amplitudes in response to the syntactic violation which was most prominent at the left
anterior electrodes. Planned comparisons to investigate the site of effect revealed,
firstly, a significant difference in the left-anterior ROI (F(1,39) = 14.93, p < 0.001) when
both groups are considered, and, secondly, a significantly larger ELAN amplitude for
the MT group in the right-anterior ROI (F(1,39) = 4.58, p = 0.039). Since the ELAN amplitude
(in the anterior ROIs) was much larger in the MT group compared to the NM
group, it was expected to find an interaction of syntactic regularity × subgroup. However,
this interaction was minimally above the significance threshold (p = 0.052).
To account for the lack of interaction of syntactic regularity × subgroup in the above
ANOVA, a further assumption was tested: As the ELAN develops until around 12 to 13
years of age (for sentences with passive mode construction; Hahne et al., 2004), it was
not expected to find an ELAN in all children. A further ANOVA with the same factors
as the ANOVA above, but with age (in months) as a covariate was computed. In this
ANOVA, the interaction of syntactic regularity × subgroup was clearly significant
(F(1,38) = 5.91, p = 0.020). Further, it revealed an interaction of syntactic regularity ×
anterior-posterior distribution × hemisphere (F(1,38) = 4.21, p = 0.047) indicating a significant
difference between the two experimental conditions that was most obvious in
the left-anterior ROI, and an interaction of syntactic regularity × anterior-posterior distribution
× hemisphere × age (F(1,38) = 4.96, p = 0.032) demonstrating an influence of
age on the ELAN amplitude. 29
Since the ANOVA with age as a covariate found an interaction of syntactic regularity ×
subgroup, the ELAN amplitude was further evaluated in two ANOVAs (with the same
within-subject factors as above) separately for each of the two sub-groups. In the MT
group, the ANOVA with age as a covariate revealed an interaction of syntactic regularity
× anterior-posterior distribution × hemisphere (F(1,19) = 9.50, p = 0.006) and an interaction
of syntactic regularity × anterior-posterior distribution × hemisphere × age
(F(1,19) = 11.29, p = 0.003). The ANOVA without age as a covariate revealed a main
effect of syntactic regularity (F(1,20) = 7.22, p = 0.014), an interaction of syntactic regularity
× anterior-posterior distribution (F(1,20) = 7.53, p = 0.012), and of syntactic regu-
29
It was not possible to use planned comparisons within this ANOVA since it is, to my knowledge, not
possible to account for a between-subjects factor and a covariate at the same time. Thus, results of the
planned comparisons from the ANOVA without age as covariate are presented in Figure 4.