Speech Processes in Adults and Children
Research in the Logan lab has focused on several basic and applied projects in the area of spoken word recognition. Our goal has been to understand the representation and processing of acoustic/phonetic information in children and adults using behavioural, electrophysiological and modeling techniques.
- The development of spoken word recognition in children. This research uses experimental procedures to determine the effect of variables such as phonological similarity (neighbourhood density and probabilistic phonotactics) on word recognition in preschoolers and how the effect of these variables changes during development. Computational modeling is also used to help formulate a theoretical account of how spoken word recognition develops in children.
- The structure of phonetic categories. Little in known about the internal structure of phonetic categories and how they accommodate talker variability during speech perception. Current research in my lab is designed to illuminate this area by exploring the whether listeners use phonetic prototypes in the perception of vowels, and if so, how they use these prototypes. Moreover, because previous work in this area only examined the vowel /i/, our research also is examining the vowels /a/ and /u/ to determine if similar characteristics are associated with other portions of the vowel space.
- Nonbehavioural audiometric testing. Traditional behavioural tasks for evaluating hearing cannot be used when manual or verbal responses are impossible. We are currently working with K. Campbell’s lab at the University of Ottawa to develop a test of hearing that does not require a behavioural response but instead utilizes an electrophysiological response to changes in the auditory environment. An initial report on the measurement of an EEG component known as mismatch negativity, which appears to have some promise as a nonbehavioural measure of auditory change, has been published.
SAMPLE OF RECENT RELATED PUBLICATIONS & PRESENTATIONS
Muller-Gass, A., Marcoux, A., Logan, J., & Campbell, K. (2001). The intensity of masking noise affects the mismatch negativity to speech sounds in human subjects. Neuroscience Letters, 299, 197-200.
Marcoux, A., Muller-Gass, A., Logan, J., & Campbell, K.B. (1999). Mismatch negativity to inclusions of noise within complex spectrotemporal sound patterns. NeuroReport, 10, 1-7.