ATR Human Information Processing Labs, 2-2 Hikaridai, Seika-cho, Soraku-gun, Kyoto 619-02, Japan
Kevin G. Munhall
Queens Univ., Canada
In previous work [Vatikiotis-Bateson et al., Proc. ICSLP-94 2, 527--530 (1994)], listener eye movements were examined during audiovisual perception. Clear effects of masking noise level were observed in the stability and location of the listener's gaze. At higher noise levels, listeners fixated primarily on the mouth and very little on the eyes. Listeners were implicitly directed to focus on phonetic detail in the stimuli, by means of questions used to determine intelligibility of the stimulus; however, attention to phonetic detail is only part of what goes on during audiovisual communication. In the current study, different patterns of eye movement were elicited from 10 English listeners by biasing the listener's focus of attention. Two listener biases were tested---one toward phonetic discriminations, as previously studied, and the other toward practic information, e.g., having to do with perceived characteristics of the speaker. If visual cues during audiovisual perception are only partly phonetic, then differences in the listener's interpretation of the experimental goals may evince different patterns of eye movement. For example, the perceived goal of the experiment may affect the relative proportion of gaze fixations on the eyes and the mouth.