Speech perception in early infancy: Perceptual constancy for spectrally dissimilar vowel categories

“However, exemplars from a single category were much more similar than those typically used in categorizing tasks (cf Kuhl, 1979).”

“by Grieser and Kuhl (1989). The stimuli were generated and goodness ratings were obtained from adult listeners in Experiment 1.”

“In the study, Iverson and Kuhl (79) used computersynthesized syllables beginning with yry and yly, spacing them at equal physical intervals in a two-dimensional acoustic grid (Fig.”

“The use of the HT technique permits the calculation of a percent correct measure and the calculation of an unbiased estimate of sensitivity, d’. However, these experimenters only reported data on the proportion of infants who met a preestablished criterion threshold (e.g., Werker & Tees, 1984) or the average number of…”

“For example, Kuhl and her colleagues ( Kuhl, 1979, 1983 ) have shown that infants can categorize stimuli according to vowel color across discriminably different variations in speaker and pitch contour.”

“In addition, young infants appear to have some form of perceptual constancy for speech, which allows them to ignore variations introduced by changes in intonation or in talkers' voices ( Kuhl, 1979, 1983 ).”

“, & Kuhl, P. K. (1979). Investigating the MESA (Multipoint Electrotactile Speech Aid): The transmission of connected discourse. Journal of the Acoustical Society of America, 65, 810-815. Spelke, E. S. (1976). Infants' intermodal perception of events.”

“Moreover, infants two to four months of age, could discriminate the /a/ – / i / native contrast using several speakers and pitch variations, thus showing that perceptual constancy for these vowel elements could be easily achieved early in development (Kuhl, 1979).”

“The ability to identify the same phoneme in different contexts and across speakers has been demonstrated at 6 months of age (Kuhl, 1979), and language specificity in this phonetic perception has also been demonstrated in 6-month- old infants (Kuhl, Williams, Lacerda, Stevens, & Lindblom, 1992).”

“However, even younger infants are able to ignore talker-specific properties under other circumstances—in particular, infants readily exhibit vowel normalization, categorizing individual exemplars according to vowel identity despite differences in speaker sex (Kuhl, 1979, 1983).”

“To date, this ability has only been reported in infants aged 4 months and older (Kuhl & Meltzoff, 1982, 1984; MacKain et al. , 1983; Walton & Bower, 1993; Patterson & Werker, 1999). The mean looking time to the match observed with infants aged 2 months (PTLT = 63.9) was virtually identical to that observed with 4.5-mo…”

“For example, 6-month-old infants recognize the acoustic categories correlated with vowel identities despite the dissimilarity of vowels produced by different speakers and in different contexts (e.g., Kuhl, 1979, 1983).”

“(e.g., Aslin, Pisoni, Hennessey, & Perey, 1981; Eilers, Wilson, & Moore, 1979; Kuhl, 1979; Menary, Trehub, & McNutt, 1982; Miller, Younger, & Morse, 1982; Werker, Gilbert, Humphrey,”

“The ability to identify a phoneme in different contexts and across speakers has been demonstrated at months of age (Kuhl 1979), and language-specific categorical perception is evident by 10-12 months of age Werker and Tees 1984).”

“By 6 mo of age, infants can distinguish speech sounds even when emitted by different speakers (Kuhl 1979).”

“As noted earlier, several previous studies have demonstrated that infants younger than 7.5 months are able to ignore talker differences in discriminating certain phonetic contrasts (e.g., Jus-czyk et al., 1992; Kuhl, 1979, 1983).”

“, & Kuhl, P. K. (2003). Investigating the role of infant-directed”

“Although one study used highly distinct vowels in the female range (Kuhl, 1979), infants’ discrimination of vowels in the range of the ID speech that infants typically hear has not been tested previously.”

“Our results also parallel those from studies of infants’ encoding of speech stimuli, which show that young infants are able to recognize particular phonetic units across changes in pitch (Cheour et al., 2002; Jusczyk, Pisoni, & Mullennix, 1992; Kuhl, 1979).”

“This was demonstrated in English infantsÕ discrimination of English /i/ versus / / (Kuhl, 1979; Marean et al., 1992) and / / versus / c / (Kuhl, 1983), two contrasts involving at least one peripheral vowel.”

“In a discrimination task, 6-month-olds weight talker differences as less important than changes in phonetic (vowel) category (Kuhl, 1979), and in a word recognition task the performance of 7.”

“In studies using vowel categories such as /a/, as in pop, compared with /i/, as in peep (Kuhl, 1979), and /a/, as in cot, compared with /a/, as in caught (Kuhl, 1983), most infants correctly classified novel instances from the two vowel categories on the first trial.”

“Kuhl and Meltzoff (1988, 1996) reported that, in a preferential-looking paradigm, 4.5-month-olds imitated the vowel that matched the vowel they both saw and heard. Legerstee (1990) presented audio and visual components of the vowels /a/ and /u/ independently to 3-month-olds.”

“Contents lists available at ScienceDirect Journal of Phonetics 0095-44 doi:10.1 Corr E-m adscut@ 1 Cu Psychol Philade Pleas perc journal homepage: www.elsevier.com/locate/phonetics Rhythmic distance between languages affects the development of speech perception in bilingual infants Megha Sundara , Adrienne Scutellaro…”

“, & Kuhl, P. K. (1993). Perceptual strategies in prelingual speech segmentation.”

“For example, it has been shown that infants exhibit some ability to deal with talker changes (Jusczyk, Pisoni & Mullenix, 1992b; Kuhl, 1979, 1983).”

“The results show definitively that infants remember the tempo and timbre of the familiarized melodies over long periods of time, because changing the tempo or timbre at test eliminates their preference for the novel melody. Thus, their long-term memory representations are not simply of the abstract musical structure,…”

“For example, in processing musical sequences, infants focus on relations among notes (i.e., melodic contour) rather than absolute pitch (Trehub, Bull, & Thorpe, 1984), much the same way that they do in generalizing across different speakers’ voices ( Kuhl, 1979 ).”

“Thus, although the primary focus of earlier research asked about what speech perception capacities are, current investigations center more on how such capacities are used in understanding and learning language.”

“Some research has suggested that in many situations infants indeed readily extract the abstract linguistic message from speech in the face of indexical variation (e.g. Jusczyk, Pisoni & Mullennix, 1992; Kuhl, 1979; Van Heugten & Johnson, 2009).”

“By 1;0, they have honed their discriminative capacities to concentrate on those speech sounds used phonemically in their native language ( Kuhl, 1979, 1983 ; Hillenbrand, 1984 ; Werker & Tees, 1984 ; Jusczyk, Pisoni & Mullennix, 1992), how often they occur (Jusczyk, Luce & Charles-Luce, 1994), how they are combined to…”

“Kuhl (1979, 1983) used this conditioned head-turning paradigm to assess categorization by beginning the task with a simple discrimination (a single repeating background token and a single target token) and then adding multiple tokens to these background and target sets.”

“By 6 months, infants can discriminate many of the speech contrasts used across the world’s languages (Kuhl, 1979; Werker & Tees, 1984).”

“During the first 6 mo, infants are sensitive to clause boundaries in connected discourse (see Table 2, Jusczyk & Luce, 2002) and are able to recognize syllables spoken by different talkers (Kuhl, 1979).”

“This procedure-as we implemented it-involves conditioning the infant to provide an operant head-turn in response to a change of phonetic category within a series of speech stimuli (Kuhl, 1979).”

“That they do so using synthesized speech or unfamiliar talkers implies that infants generalize across talkers under some conditions (Johnson, Seidl, & Tyler, 2014; Kuhl, 1979; Kuhl et al., 2006; Polka & Werker, 1994; van Heugten & Johnson, 2012; Werker & Tees, 1984, inter alia).”

“Furthermore, by about 6 mo of age, infants can form equivalent classes of phonetic categories, despite the acoustic variation from different speakers, intonation, and phonetic context (Kuhl 1979, 1983; Kuhl et al. 2003).”

“First, the CSVs cannot be just reduced realization of OSVs, although CSVs were much shorter and short vowels are commonly realized with undershot vowel targets of their longer counterparts (Lindblom, 1963; see empirical support from Japanese (Keating & Huffman, 1984), Scottish Gaelic (Ladefoged, Ladefoged, Turk, Hind,…”

“Studies have shown that infants can discriminate between different speakers (DeCasper & Fifer, 1980; Jusczyk, Pisoni, & Mullennix, 1992) and can generalize speech sounds across different speakers (Kuhl, 1979, 1983).”

“The supporting facts are partially observed in developmental psychology [12, 13].”

“An operant headturning paradigm might be a viable training procedure by which to test these proposals (e.g., Husaim & Cohen, 1981; Kuhl, 1979).”

“…perception, research on infant speech perception has shown that perceptual normalization of segmental variability in vowels and consonants has already happened in infants before the onset of speech production (e.g., Kuhl, 1976, 1979, 1983; Kuhl & Miller, 1982; Jusczyk, Pisoni, & Mullenix, 1992).”