Mature neural responses to Infant-Directed Speech but not Adult-Directed Speech in Pre-Verbal Infants

Abstract

Infant directed speech (IDS), the speech register adults use when talking to infants, has been shown to have positive effects on attracting infants’ attention, language learning, and emotional communication. Here event related potentials (ERPs) are used to investigate the neural coding of IDS and ADS (adult directed speech) as well as their discrimination by both infants and adults. Two instances of the vowel /i/, one extracted from ADS and one from IDS, were presented to 9-month-old infants and adults in two oddball conditions: ADS standard/IDS deviant and IDS standard/ADS deviant. In Experiment 1 with adults, the obligatory ERPs that code acoustic information were different for ADS and IDS; and discrimination, indexed by mismatch negativity (MMN) responses, showed that IDS and ADS deviants were discriminated equally well; although, the P3a response was larger for IDS suggesting it captured adults’ attention more than did ADS. In infants the obligatory responses did not differ for IDS and ADS, but for discrimination, while IDS deviants generated both a slow-positive mismatch response (MMR) as well as an adult-like MMN, the ADS deviants generated only an MMR. The presence of a mature adult-like MMN suggests that the IDS stimulus is easier to discriminate for infants.

The role of the visual association cortex in scaffolding prefrontal cortex development: A novel mechanism linking socioeconomic status and executive function

“…Children prefer speech with these properties, and these unique acoustic characteristics have been shown to direct children’s attention to different visual information in the environment (Cooper and Aslin, 1990; Golinkoff et al, 2015; Kaplan et al, 1996; Segal and Newman, 2015; Suttora et al, 2017; Werker and McLeod, 1989). Moreover, infants show increased PFC activity in response to child-directed speech but not adult-directed speech (Peter et al, 2016; Santesso et al, 2007; Zangl and Mills, 2007). For example, caregivers highlight important aspects of children’s complex visual world both by drawing their attention to cues the caregiver wants to highlight and by engaging with aspects of the environment in which the child is engaged and helping them pull important features out of a background of visual complexity.…”

Infant‐directed speech to infants at risk for dyslexia: A novel cross‐dyad design

“…For instance, it has been proposed that both these features, despite appearing to counteract each other, may be consistent with acoustic adjustments aimed at facilitating language teaching (Eaves, Feldman, Griffiths, & Shafto, ). In addition, infants have been shown to benefit from exposure to exaggerated versus non‐exaggerated vowels in experiments assessing vowel perception (Peter, Kalashnikova, Santos, & Burnham, ; Zhang et al, ) and lexical processing (Song, Demuth, & Morgan, ). Moreover, the degree to which individual mothers hyperarticulate vowels in IDS is positively related to their infants’ concurrent and later linguistic abilities: Mothers who exaggerate vowels to a greater extent have infants who are more successful in discriminating native phonetic contrasts at the ages of 6–8 and 10–12 months (Liu, Kuhl, & Tsao, ) and have infants who have larger vocabulary sizes in the second year of life (Hartman, Ratner, & Newman, ; Kalashnikova & Burnham, ).…”

Infant-directed speech facilitates seven-month-old infants’ cortical tracking of speech

“…Second, exposure to IDS appears to facilitate linguistic processing during the child’s first years of life. Behavioural and neurophysiological studies indicate that IDS is better than ADS in promoting performance on a variety of linguistic tasks such as speech sound discrimination 30 , 31 , familiar word recognition 32 , 33 , and word learning 34 , 35 . Thus, it is possible that by using IDS, parents unconsciously produce not only the type of speech that their infants attend to and prefer, but also the type of speech that assists their infants in the challenging task of learning their native language 36 .…”