Interestingly, while inverting the orientation of the face
reduced audiovisual integration for stimuli with normal configuration,
it improved audiovisual integration for Thatcherized
stimuli. This could indicate a role for the orientation of the mouth
segment. To investigate this, we conducted a separate two-way,
repeated-measures ANOVA on normal, upright and Thatcherized,
inverted stimuli, which share direction of the mouth segment but
within either a matching or conflicting facial orientation. The
difference in the strength of the McGurk illusion was significant
(F(1,10)=31.36, P