The Distribution of Talker Variability Impacts Infants’ Word Learning

Infants’ selective use of reliable cues in multidimensional language input.

“…Contrary to our predictions, dividing information streams by speaker did not facilitate infants’ learning in either experiment. Though indexical information may initially be salient for infants (e.g., Jusczyk et al, 1992; Singh et al, 2004; Quam, Knight, & Gerken, 2017), 10-month-old infants can generalize across speakers, suggesting that they learn that differences between speakers are not always meaningful (Houston & Jusczyk, 2000). Indeed, when listening to unfamiliar speech, infants are less sensitive to individual voices, presumably because differences between languages are more salient than differences between speakers (e.g., Johnson, Westrek, Nazzi, & Cutler, 2011; Nazzi et al, 2000).…”

Only the right noise? Effects of phonetic and visual input variability on 14‐month‐olds' minimal pair word learning

“…Another factor that modulates performance is the degree of acoustic variability of repeated instances of the words. In minimal pair word learning settings using the habituation‐switch paradigm, 14‐month‐old infants showed better performance when the acoustic stimuli were drawn from recordings of multiple speakers compared to a single speaker (Quam, Knight, & Gerken, 2017; Rost & McMurray, 2009, 2010) and also when a high number of different exemplars from a single speaker who was instructed to produce them with varying pitch and duration was used as stimuli (Galle, Apfelbaum, & McMurray, 2015). Bortfeld and Morgan (2010) found that even 7.5‐month‐old infants' ability to detect words in fluent speech was enhanced when these words alternated between emphatic and non‐emphatic productions.…”

Infants' discrimination of consonant contrasts in the presence and absence of talker variability

“…The final trial was a post-test, novel trial included to check whether infants were still attending to the task, by confirming that their attention perked up when they heard an entirely new word form: /paez/ for infants familiarized to / bIm/ and /baez/ for infants familiarized to /pIm/. Novel stimuli were pulled from a larger set of /b/-and /p/-initial stimuli recorded for the prior study (Quam et al, 2017) and chosen in particular for being highly distinct from /pIm/-/bIm/ in their nuclei and codas. Statistical analyses are conducted on the looking times recorded online by the experimenter.…”

“…1 It is interesting that rates of fussiness (11) and failure to habituate (two) in Experiment 2 were higher than Experiment 1 (six excluded for fussiness, and zero failed to habituate). In a prior study (Quam, Knight, & Gerken, 2017), training that was more complex, due to pairing talker gender with words, led to more fussiness (23 children excluded of 59 tested, or 39%) than a training context that was simpler, containing talker variability that varied randomly (six children excluded of 24 tested, or 25%; see also Gerken, Wilson, & Lewis, 2005). In Experiment 2, both of the children who failed to habituate and 8/11 of the children excluded for fussiness were tested in the multiple-talker condition.…”