scholarly journals Lexically guided perceptual tuning of internal phonetic category structure

2016 ◽  
Vol 140 (4) ◽  
pp. EL307-EL313 ◽  
Author(s):  
Julia R. Drouin ◽  
Rachel M. Theodore ◽  
Emily B. Myers
Keyword(s):  
Category Structure ◽  
Phonetic Category

Phonetic Category Structure of [I]

1997 ◽  
Vol 40 (6) ◽  
pp. 1406-1424 ◽  
Author(s):  
Joan E. Sussman ◽  
Brian Gekas
Keyword(s):  
Category Structure ◽  
Prototype Theory ◽  
Current Investigation ◽  
Phonetic Category ◽  
Phonetic Categories ◽  
Vowel Categories ◽  
Fixed Standard

The current investigation examined the structure of the phonetic category [I] for 13 listeners. Experiments reported are results from identification, "best exemplar," and discrimination tasks using 105 [I] stimuli. The tokens were synthesized along a mel-spaced vowel continuum that differed in first and second formants. All stimuli ended in a 30 ms [b] sound. Results showed that 10 of 13 listeners demonstrated differing choices of the best exemplars, although most were within 37.5 mels of the central best exemplar chosen in the first experiment. Seven of the participants demonstrated "circular" patterns in identification of the [I] category that appeared to be organized around a central "best exemplar." Six participants showed other identification patterns: "downward, " "upward," and "left-extending," with "best exemplars" on an edge or border of the phonetic categories. Graded category structure from a central "best exemplar" was apparent only in the averaged identification results, and not for individual participants. The size of the [I] category was significantly smaller than that surrounding the [i] best exemplar reported in a prior study by Sussman and Lauckner-Morano (1995). Finally, listeners had equivalent or better discrimination sensitivity with the best exemplar as the fixed standard compared to that for a "poor" exemplar token 45 mels away from the best exemplar. Results showed that phonetic category structure for the lax vowel [I] was different from the similar, but tense vowel [i]. The findings question whether prototype theory is generalizable to vowel categories other than [i].

Talker-specific influences on phonetic category structure

2015 ◽  
Vol 138 (2) ◽  
pp. 1068-1078 ◽  
Author(s):  
Rachel M. Theodore ◽  
Emily B. Myers ◽  
Janice A. Lomibao
Keyword(s):  
Category Structure ◽  
Phonetic Category

The Perception of Voice Onset Time: An fMRI Investigation of Phonetic Category Structure

2005 ◽  
Vol 17 (9) ◽  
pp. 1353-1366 ◽  
Author(s):  
Sheila E. Blumstein ◽  
Emily B. Myers ◽  
Jesse Rissman
Keyword(s):  
Voice Onset Time ◽  
Inferior Frontal Gyrus ◽  
Onset Time ◽  
Superior Temporal Gyrus ◽  
Category Boundary ◽  
Category Membership ◽  
Category Structure ◽  
Angular Gyrus ◽  
Middle Temporal Gyrus ◽  
Phonetic Category

This study explored the neural systems underlying the perception of phonetic category structure by investigating the perception of a voice onset time (VOT) continuum in a phonetic categorization task. Stimuli consisted of five synthetic speech stimuli which ranged in VOT from 0 msec ([da]) to 40 msec ([ta]). Results from 12 subjects showed that the neural system is sensitive to VOT differences of 10 msec and that details of phonetic category structure are retained throughout the phonetic processing stream. Both the left inferior frontal gyrus (IFG) and cingulate showed graded activation as a function of category membership with increasing activation as stimuli approached the phonetic category boundary. These results are consistent with the view that the left IFG is involved in phonetic decision processes, with the extent of activation influenced by increased resources devoted to resolving phonetic category membership and/or selecting between competing phonetic categories. Activation patterns in the cingulate suggest that it is sensitive to stimulus difficulty and resolving response conflict. In contrast, activation in the posterior left middle temporal gyrus and the left angular gyrus showed modulation of activation only to the “best fit” of the phonetic category, suggesting that these areas are involved in mapping sound structure to its phonetic representation. The superior temporal gyrus (STG) bilaterally showed weaker sensitivity to the differences in phonetic category structure, providing further evidence that the STG is involved in the early analysis of the sensory properties of speech.

Sign in / Sign up

Export Citation Format

Share Document