Asymmetries in unimodal visual vowel perception: The roles of oral-facial kinematics, orientation, and configuration.

Abstract

Masapollo, Polka, and Ménard (2017) recently reported a robust directional asymmetry in unimodal visual vowel perception: Adult perceivers discriminate a change from an English /u/ viseme to a French /u/ viseme significantly better than a change in the reverse direction. This asymmetry replicates a frequent pattern found in unimodal auditory vowel perception that points to a universal bias favoring more extreme vocalic articulations, which lead to acoustic signals with increased formant convergence. In the present article, the authors report 5 experiments designed to investigate whether this asymmetry in the visual realm reflects a speech-specific or general processing bias. They successfully replicated the directional effect using Masapollo et al.'s dynamically articulating faces but failed to replicate the effect when the faces were shown under static conditions. Asymmetries also emerged during discrimination of canonically oriented point-light stimuli that retained the kinematics and configuration of the articulating mouth. In contrast, no asymmetries emerged during discrimination of rotated point-light stimuli or Lissajou patterns that retained the kinematics, but not the canonical orientation or spatial configuration, of the labial gestures. These findings suggest that the perceptual processes underlying asymmetries in unimodal visual vowel discrimination are sensitive to speech-specific motion and configural properties and raise foundational questions concerning the role of specialized and general processes in vowel perception. (PsycINFO Database Record

Bringing the Nonlinearity of the Movement System to Gestural Theories of Language Use: Multifractal Structure of Spoken English Supports the Compensation for Coarticulation in Human Speech Perception

“…For gestural theories, compensation for coarticulation reflects speech perception's capacity to bypass low-dimensional acoustic variability (i.e., in frequency means or intensity patterns) and to find invariant structure in gestures (Fowler, 2006 ). These gestures set up a context that shapes the perception of a target phoneme, but because gestures are themselves context-sensitive, gestural theories encompass a broad set of structures unfolding and interacting with one another across a variety of time scales, e.g., the entire phrase in which a phoneme occurs (Tilsen, 2009 ), the surrounding discourse (Skipper et al, 2017 ), the facial movements implicated in articulation (Massapollo et al, 2018 ), the social setting and concurrent multimodal sensory information (Levinson and Holler, 2014 ), the language itself (Tobin et al, 2017 ). Compared with the extremely stringent just-previous-sound definition of context from general-auditory theorists, the gestural-theoretic context risks seeming sprawling and perhaps unfalsifiably vast.…”

Asymmetric discrimination of nonspeech tonal analogues of vowels.

“…By this account, the foregoing findings do not derive from basic psychoacoustic processes. Indeed, recent results have provided evidence that is compatible with this view (Polka & Bohn, 2011; Masapollo et al ., 2018; Masapollo et al ., under review). For example, Masapollo, Franklin, Morgan and Polka (under review) found that asymmetries in adult vowel perception were diminished in discrimination tasks that reduced demands on phonological working memory.…”

“…Another focus was on how factors such as phonological working memory capacity, attention, and particular task demands interact to influence asymmetries. This framework has been used to guide a number of recent studies of vowel perception with both adults and infants (see, e.g., Pons et al ., 2012; Tyler, Best, Faber, & Levitt, 2014; Kriengwatana & Escudero, 2017; Masapollo, Polka, Molnar, & Ménard, 2017a; Masapollo, Polka, & Ménard, 2017b; Masapollo, Polka, Ménard, Franklin, Tiede & Morgan, 2018; Masapollo, Franklin, Morgan & Polka, under review), which have informed our understanding of the nature of the interplay between initial discrimination abilities and biases and linguistic experience in vowel perception.…”

Asymmetries in Accessing Vowel Representations Are Driven by Phonological and Acoustic Properties: Neural and Behavioral Evidence From Natural German Minimal Pairs

“…Therefore, the authors argued that there is a universal bias towards more focalized vowels in adults, too. These results have been replicated and extended in that the universal bias seems to have an impact not only on the auditory domain of speech processing but also on visual vowel discrimination (Masapollo et al, 2017a , 2018 ).…”