Predictive brain signals of linguistic development
Kooijman, V.M. ; Junge, C. ; Johnson, E.K. ; Hagoort, P. ; Cutler, A. - \ 2013
Frontiers in Psychology 4 (2013). - ISSN 1664-1078
event-related potentials - word segmentation - language-development - speech-perception - electrophysiological evidence - cerebral specialization - american infants - native-language - 1st year - recognition
The ability to extract word forms from continuous speech is a prerequisite for constructing a vocabulary and emerges in the first year of life. Electrophysiological (ERR) studies of speech segmentation by 9- to 12-month-old listeners in several languages have found a left-localized negativity linked to word onset as a marker of word detection. We report an ERR study showing significant evidence of speech segmentation in Dutch-learning 7-month-olds. In contrast to the left-localized negative effect reported with older infants, the observed overall mean effect had a positive polarity. Inspection of individual results revealed two participant sub-groups: a majority showing a positive-going response, and a minority showing the left negativity observed in older age groups. We retested participants at age three, on vocabulary comprehension and word and sentence production. On every test, children who at 7 months had shown the negativity associated with segmentation of words from speech outperformed those who had produced positive-going brain responses to the same input. The earlier that infants show the left-localized brain responses typically indicating detection of words in speech, the better their early childhood language skills.
Rapid recognition at 10 months as a predictor of language development
Junge, C. ; Kooijman, V.M. ; Hagoort, P. ; Cutler, A. - \ 2012
Developmental Science 15 (2012)4. - ISSN 1363-755X - p. 463 - 473.
event-related potentials - word segmentation - continuous speech - phonotactic knowledge - sound patterns - infants - brain - acquisition - nonsense - memory
Infants' ability to recognize words in continuous speech is vital for building a vocabulary. We here examined the amount and type of exposure needed for 10-month-olds to recognize words. Infants first heard a word, either embedded within an utterance or in isolation, then recognition was assessed by comparing event-related potentials to this word versus a word that they had not heard directly before. Although all 10-month-olds showed recognition responses to words first heard in isolation, not all infants showed such responses to words they had first heard within an utterance. Those that did succeed in the latter, harder, task, however, understood more words and utterances when re-tested at 12 months, and understood more words and produced more words at 24 months, compared with those who had shown no such recognition response at 10 months. The ability to rapidly recognize the words in continuous utterances is clearly linked to future language development.