Speaker Variations Influence Speechreading Speed for Dynamic Faces

Interactions between the perception of age and ethnicity in faces: an event-related potential study

Face perception models propose that different facial attributes are processed by anatomically distinct neural pathways that partially overlap. Whether these attributes interact functionally is an open question. Our goal was to determine if there are interactions between age and ethnicity processing and, if so, at what temporal epoch these interactions are evident. We monitored event-related potentials on electroencephalography while subjects categorized faces by age or ethnicity in two conditions: a baseline in which the other of these two properties not being categorized was held constant and an interference condition in which it also varied, as modelled after the Garner interference paradigm. We found that, when participants were categorizing faces by age, variations in ethnicity increased the amplitude of the right face-selective N170 component. When subjects were categorizing faces by ethnicity, variations in age did not alter the N170. We concluded that there is an asymmetric pattern of influence between age and ethnicity on early face-specific stages of visual processing, which has parallels with behavioural evidence of asymmetric interactions between identity and expression processing of faces.

Alignment to visual speech information

Speech alignment is the tendency for interlocutors to unconsciously imitate one another's speaking style. Alignment also occurs when a talker is asked to shadow recorded words (e.g., Shockley, Sabadini, & Fowler, 2004). In two experiments, we examined whether alignment could be induced with visual (lipread) speech and with auditory speech. In Experiment 1, we asked subjects to lipread and shadow out loud a model silently uttering words. The results indicate that shadowed utterances sounded more similar to the model's utterances than did subjects' nonshadowed read utterances. This suggests that speech alignment can be based on visual speech. In Experiment 2, we tested whether raters could perceive alignment across modalities. Raters were asked to judge the relative similarity between a model's visual (silent video) utterance and subjects' audio utterances. The subjects' shadowed utterances were again judged as more similar to the model's than were read utterances, suggesting that raters are sensitive to cross-modal similarity between aligned words.

Does face familiarity influence speechreadability?

The impact of face familiarity on the speechreadability of faces is examined. First we measured the baseline speechreading performance of participants, from unfamiliar faces. Next, participants were familiarized with the face and voice of either the same or a different speaker, or were asked to take part in a word puzzle instead. Speechreading performance was measured again, before participants completed a further period of familiarization (or puzzle completion) and a final speechreading performance task. Results showed that speechreading performance increased overall with practice but that performance increased significantly more as participants became increasingly familiar with the same speaker. Our findings demonstrate the importance of talker-specific variations or other instance-based characteristics and suggest that these are a useful source of information for speechreading.