Table 3. Analyses of ROIs created from trials classified with alternative method.

Participants viewed short trials of audiovisual speech. For each subject, all trials were sorted by the amount of time fixating the mouth region of the talker’s face; trials with greater than 50% of time spent fixating the mouth were classified as mouth trials and the remained were classified as eye trials. The contrast of brain activations between mouth vs. eye trials was used to define mouth and eye selective regions of the pSTS. The response of these mouth and eye ROIs to a separate experimental condition consisting of blocks of auditory-only (A), visual-only (V) and audiovisual (AV) speech were calculated for each participant and entered into a linear mixed-effects model. The linear mixed-effects model had fixed factors of ROI (mouth, eye) and stimulus (A, V, AV) with participant as a random factor and participant × stimulus as a random interaction. The first three rows show the mean response to A, V and AV conditions in mouth and eye ROIs and the contrast between mouth and eye ROIs using reduced linear mixed-effects (tested with chi square tests). The next rows show the parameter estimates for each factor in the model (the baseline condition was the response to A speech in the eye ROI). The final rows show the results of chi square tests of the models.

Mouth ROI vs. Eye ROI	df	χ2	p	Mouth ROI	Eye ROI
A Stim	1	15.24	9.5 × 10−5	0.69%	0.38%
V Stim	1	0.13	0.72	0.27%	0.25%
AV Stim	1	15.29	9.2 × 10−5	1.04%	0.71%

	Estimate	Std. Error	df	t	p
Fixed effects
Baseline (A)	0.387	0.056	228.5	6.91	4.7 × 10−11
Mouth ROI	0.307	0.075	305.4	4.11	5.0 × 10−5
AV Stim	0.325	0.073	290.6	4.42	1.4 × 10−5
V Stim	−0.133	0.073	290.6	−1.81	0.071
Mouth ROI × AV Stim	0.027	0.104	290.6	0.26	0.797
Mouth ROI × V Stim	−0.283	0.104	290.6	−2.71	0.007
Random effects	Variance
Participant	0.000
Participant × AV Stim	0.029
Participant × V Stim	0.004

Main effects	df	χ2	p
ROI	1	26.58	4.7 × 10−7
Stimulus	2	137.83	< 2.2 × 10−16
Interaction
ROI ×Stimulus	2	10.85	0.004