In order to investigate the apparent discrepancy between the
MMN and behavioral data we calculated the correlation between the
mean MMN amplitude in the 100–140 ms interval and the difference
in incorrect identifications between incongruent and congruent
stimuli conditions across all subjects and conditions (cf. Fig. 3). The
correlation between MMN amplitude and this behavioral McGurk
measure was not significant (P>0.2). As the estimated correlation
may depend on the behavioral measure being constrained to values
between zero and one, we also calculated the correlation between
the MMN amplitude and the Z-score (P>0.2; only for values greater
than zero and less than one); as well as between the MMN amplitude
and the arcsine transformed behavioral measure (P>0.1) but this
only confirmed the lack of correlation.