Asst. Professor
The University of California at Santa Cruz
Department of Linguistics
Stevenson Faculty Services
Santa Cruz, CA 95064
gmcguir1 (at) ucsc (dot) edu
I am primarily studying perception as it relates to phonetics and phonology. My current research is aimed at perceptual learning, phonetic categorization and language specific perception. I have been tackling these issues through training and discrimination experiments. Previously, I have looked into interdental fricative substitution and am generally interested in perception and laboratory phonology.
Selective attention and dimensional sensitivity
This project, using both speech and non-speech stimuli, explores how selective attention to different dimensions affects categorization and sensitivity to contrasts. So far results demonstrate that attending to a dimension relevant to categorization increases sensitivity to that dimension relative to unattended dimensions. Moreover, learning to attend to a dimension can generalize to new areas of perceptual space.
Cue covariance and the formation of higher-level perceptual units (with Angela Aiello and Ryan Bennett, UCSC)
Certain speech cues are known to be integrated, or fused, into larger perceptual units. The reasons why some cues are integrable while others are separable is still controversial. The goal of this study is to examine the hypothesis that the predictable co-variance of cues drives integration, even when those cues have disparate perceptual effects or the gestures that give rise to them are not articulatorily related.
Effects of the distribution of acoustic cues on infants' perception of speech sounds (with Alejandrina Cristia, École Normale Supérieure, Amanda Seidl and Alex Francis, Purdue)
This is an infant perception study examining how 4mth olds learn categories from multidimensional distributions. We found that infants displayed different patterns of attention depending on the acoustic distribution of cues they heard during initial exposure, and their performance was equally good for the vocalic and the consonantal dimensions. However, this learning occurred only in one perceptual region, close to one category. In a second experiment, infants heard a highly kurtotic unimodal distribution, with the mode centered in the previously unlearned category. However there was no evidence of learning in this condition.
The phonetic effects of exercise-induced hyperpneic speech (with Sam Tilsen, USC)
This study examines the phonetic effects of hyperpneic, or out-of-breath speech. This condition is especially interesting because the strongest physical urge due to hyperpnea is not a need to inhale, but a need to exhale CO2. This conflicts with the need to maintain steady subglottal pressure for modal phonation. By putting in conflict these two needs we hope to better understand the roles of automaticity and control in speech production more generally.
The role of visual cues in non-sibilant fricative perception (with Molly Babel, U of British Columbia)
Though speech perception has generally focused on auditory cues, visual cues are known to play a significant role. This project examines how much visual cues contribute to the identification of a challenging contrast, /f/ 'deaf' and /th/ 'death'. These sounds are acoustically very similar, but have different visual cues. Across languages and various English dialects, /th/ frequently changes to /f/, but the reverse rarely happens. Our project examines the extent to which the salience of visual information contributes to the direction of this trend and how individual talkers modulate this effect.
Exploring the bases of vowel dispersion (with Jaye Padgett, UCSC)
While the shapes of vowel systems are often seen as the product of perceptual dispersion, the cause of this phenomenon is debated. Though Lindblom attributes dispersion to the communicative needs of speakers, others attribute it to automatic processes independent of communicative saliency. This project attempts to test these two concepts by examining dispersion over a brief time-course in a highly localized context.
I am currently teaching Language and Social Identity.
Previously I have taught Phonetic Analysis and a seminar on Perceptual Learning