This has, to our
knowledge, not been investigated for the McGurk-MMN. To
investigate if the relationship between the perceived difference
and the McGurk-MMN amplitude could be nonlinear we calculated
the minimal behavioral response (difference in percentage
incorrect between congruent and incongruent conditions) that
elicited MMN negativity for all subjects in all conditions. We found
that for behavioral measures of 75 percent points and above there
was a consistent MMN. For behavioral measures below 75 percent
points we found that the MMN was much more variable. This
indicates that the McGurk illusion needs to be very strong to elicit
the MMN consistently.