Studies of the McGurk effect have shown that when discrepant phonetic information is delivered to the auditory and visual modalities, the information is combined into a new percept not originally presented to either modality. In typical experiments, the auditory and visual speech signals are generated by the same talker. The present experiment examined whether a discrepancy in the gender of the talker between the auditory and visual signals would influence the magnitude of the McGurk effect. A male talker's voice was dubbed onto a videotape containing a female talker's face, and vice versa. The gender-incongruent videotapes were compared with gendercongruent videotapes, in which a male talker's voice was dubbed onto a male face and a female talker's voice was dubbed onto a female face. Even though there was a clear incompatibility in talker characteristics between the auditory and visual signals on the incongruent videotapes, the resulting magnitude of the McGurk effect was not significantly different for the incongruent as opposed to the congruent videotapes. The results indicate that the mechanism for integrating speech information from the auditory and the visual modalities is not disrupted by a gender incompatibility even when it is perceptually apparent. The findings are compatible with the theoretical notion that information about voice characteristics of the talker is extracted and used to normalize the speech signal at an early stage of phonetic processing, prior to the integration of the auditory and the visual information.Over the past four decades, extensive research has been done on the psychological processes underlying the perception and production of spoken language. Much of this research has focused on how the listener processes the acoustic structure of speech in order to arrive at the intended meaning of an utterance.Although speech perception has primarily been considered an auditory process, recent studies have shown that visual information provided by movements of a talker's mouth and face strongly influences what an observer perceives (Green

Of interest in the current study was how voice inset time (VOT) was influenced by changes in speaking rate across Spanish and English. Three groups of subjects (English monolinguals, Spanish monolinguals and early Spanish-English bilinguals) produced sentences containing voiced and voiceless bilabial stops at different speaking rates. As in previous research, English monolinguals showed rate-dependent effects on their VOT productions: VOT increased as speaking rate decreased. Spanish monolinguals showed a large effect of speaking rate on the duration of prevoicing of the voiced stops. However, they showed only a small effect of rate on the VOT of their voiceless stops. The bilinguals produced VOT values in each language that were nearly identical to their monolingual counterparts. The results from this study indicate that short-lag stops experience minimal variation as a function of speaking rate regardless of the other contrasting phonetic categories within a particular language. In addition, early bilinguals showed evidence of separate representations for voiced and voiceless stops for English and Spanish.

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Three experiments examined whether image manipulations known to disrupt face perception also disrupt visual speech perception. Research has shown that an upright face with an inverted mouth looks strikingly grotesque whereas an inverted face and an inverted face containing an upright mouth look relatively normal. The current study examined whether a similar sensitivity to upright facial context plays a role in visual speech perception. Visual and audiovisual syllable identification tasks were tested under 4 presentation conditions: upright face-upright mouth, inverted face-inverted mouth, inverted face-upright mouth, and upright face-inverted mouth. Results revealed that for some visual syllables only the upright face-inverted mouth image disrupted identification. These results suggest that upright facial context can play a role in visual speech perception. A follow-up experiment testing isolated mouths supported this conclusion.

The acoustic structure of the speech signal is extremely variable due to a variety of contextual factors, including talker characteristics and speaking rate. To account for the listener's ability to adjust to this variability, speech researchers have posited the existence of talker and rate normalization processes. The current study examined how the perceptual system encoded information about talker and speaking rate during phonetic perception. Experiments 1-3 examined this question, using a speeded classification paradigm developed by Garner (1974). The results of these experiments indicated that decisions about phonemic identity were affected by both talker and rate information: irrelevant variation in either dimension interfered with phonemic classification, While rate classification was also affected by phoneme variation, talker classification was not. Experiment 4 examined the impact of talker and rate variation on the voicing boundary under different blocking conditions, The results indicated that talker characteristics influenced the voicing boundary when talker variation occurred within a block of trials only under certain conditions, Rate variation, however, influenced the voicing boundary regardless of whether or not there was rate variation within a block of trials. The findings from these experiments indicate that phoneme and rate information are encoded in an integral manner during speech perception, while talker characteristics are encoded separately.Research over the past 30 years has revealed numerous aspects of the acoustic signal that playa role in phonetic perception, Theories of speech perception have attempted toexplain how these acoustic characteristics are processed, integrated, and mapped onto the underlying phonetic representations, Such explanations have been hampered by the complex relationship between the characteristics of the signal and the underlying phonetic representations.