Abstract
Previous research has shown that infants viewing speaking faces shift their visual fixation from speaker's eyes to speaker's mouth between 4-8 mo. (Lewkowicz and Tift, 2011). It is theorized that this shift occurs in order to facilitate language learning, based on audiovisual redundancy in the speech signal. In a recent study, we found that adult participants gazed significantly longer at speaker's mouths while seeing and hearing unfamiliar language compared with seeing and hearing their native language (VSS, 2013). These findings suggest that there may be a mechanism, common to both infant and adults perceivers, in which gaze fixations to a speaking mouth are increased in response to the uncertainty in the underlying speech. If so, increasing familiarity with a speech signal may reduce this tendency to fixate the mouth. To test this, the current study investigated the effect of familiarization to non-native language on the gaze patterns of adults. We presented English-speaking, monolingual adults with videos of a female reciting short sentences in Icelandic. To ensure they were encoding the speech, participants performed a simple task in which they were presented with video clips of two different sentences, followed by an audio-only recording of one of the sentences, and had to identify whether the first or second video clip corresponded to the audio. In order to familiarize participants with the utterances, the same set of sentences were repeated, in pseudo-random order, across consecutive 'repetition' blocks. In addition, we presented 'novel' blocks, using sentences not previously presented. We found that the proportion of fixations directed at the mouth decreased for repetition blocks, but not for novel blocks. These results suggest that familiarity with utterances, even in a non-native language, serve to reduce auditory uncertainty, leading to reduced mouth fixations.
Meeting abstract presented at VSS 2014