Laterality in visual speech perception.

Abstract

The lateralization of visual speech perception was examined in 3 experiments. Participants were presented with a realistic computer-animated face articulating 1 of 4 consonant-vowel syllables without sound. The face appeared at 1 of 5 locations in the visual field. The participants' task was to identify each test syllable. To prevent eye movement during the presentation of the face, participants had to carry out a fixation task simultaneously with the speechreading task. In one study, an eccentricity effect was found along with a small but significant difference in favor of the right visual field (left hemisphere). The same results were found with the face articulating nonlinguistic mouth movements (e.g., kiss). These results suggest that the left-hemisphere advantage is based on the processing of dynamic visual information rather than on the extraction of linguistic significance from facial movements.

Activation in Primary Auditory Cortex during Silent Lipreading Is Determined by Sex

“…This is in agreement with previous results on laterality in lipreading [Campbell et al, 1996;Smeele et al, 1998]. Also heard speech is strongly left lateralized in subjects [for review see Tervaniemi and Hugdahl, 2003].…”

Gaze behavior in audiovisual speech perception: The influence of ocular fixations on the McGurk effect

“…The reported visual field advantages are, however, not fully consistent. Although both left-field (R. Campbell, 1986) and right-field (R. Campbell, de Gelder, & de Haan, 1996) advantages have been observed for static face tasks, a right visual field advantage was reported for silent speechreading (Smeele, Massaro, Cohen, & Sittig, 1998). Two other studies (Baynes, Funnell, & Fowler, 1994;Diesch, 1995) also showed a right visual field advantage for the audiovisual fusion effect provided by incongruent McGurk stimuli such as ours.…”

“…Two other studies (Baynes, Funnell, & Fowler, 1994;Diesch, 1995) also showed a right visual field advantage for the audiovisual fusion effect provided by incongruent McGurk stimuli such as ours. Most of these studies used small gaze displacements (,5º from central fixation) and did not directly manipulate stimulus eccentricities, with the exception of Smeele and colleagues (Smeele et al, 1998), who reported a reliable decrease in speechreading performance when the subject's gaze was displaced eccentrically (but within 10º) from the talking face. Although different in design, the small decrease in speechreading performance reported in the latter study is consistent with the effects of gaze fixation position on the perception of the McGurk effect that we observed.…”

Optimizing Visual Feature Perception for an Automatic Wearable Speech Supplement in Face-to-Face Communication and Classroom Situations

“…The side of the face that is closest to the display may be an important variable, since this determines whether the visual features well be seen to the right or left of the talking face. There is a large literature on hemifield effects in visual perception and language processing and, although the research is not conclusive (Smeele et al, 1998), it would be advantageous to choose the side that leads to best performance. Thus, we will systematically vary whether the LED display is shown on the left side of the left lens or on the right side of the right lens.…”

“…To obtain information from the face, the perceiver does not have to fixate directly on the talker's lips but can be looking at other parts of the face or even somewhat away from the face [9]. Furthermore, accuracy is not dramatically reduced when the facial image is blurred (because of poor vision, for example), when the face is viewed from above, below, or in profile, or when there is a large distance between the talker and the viewer [5,10,11].…”