Effects of talker variability on speechreading.

The effects of talker variability on visual speech perception were tested by having subjects speechread sentences from either single-talker or mixed-talker sentence lists. Results revealed that changes in talker from trial to trial decreased speechreading performance. To help determine whether this decrement was due to talker change--and not a change in superficial characteristics of the stimuli--Experiment 2 tested speechreading from visual stimuli whose images were tinted by a single color, or mixed colors. Results revealed that the mixed-color lists did not inhibit speechreading performance relative to the single-color lists. These results are analogous to findings in the auditory speech literature and suggest that, like auditory speech, visual speech operations include a resource-demanding component that is influenced by talker variability.