Sign language, like spoken language, promotes object categorization in young hearing infants

The link between non-human primate vocalizations and cognition is not constrained by maturation alone: Evidence from healthy preterm infants

To acquire language, infants must not only identify the signals of their language(s), but also discover how these signals are connected to meaning. By 3 months of age, infants' native language, non-native languages, and vocalizations of non-human primates support infants' formation of object categories-a building block of cognition. But by 6 months, only the native language exerts this cognitive advantage. Prior work with preterm infants indicates that maturation constrains this developing link between the native language and cognition. Here, we assess whether maturation exerts similar constraints on the influence of non-human primate vocalizations on infant categorization. Cross-sectional growth curve analyses of new data from preterm infants and extant data from fullterm infants indicate that developmental tuning of this signal's influence on categorization is best predicted by infants' chronological age, and not gestational status. This evidence, together with prior work, suggests that as infants tune the initially broad set of signals that support early cognition, they are guided by two independent processes: maturation constrains the expression of a link between their native language and cognition, while the influence of non-linguistic signals are guided by other factors, such as postnatal age and experience.

Developmental origin of a language-cognition interface in infants: Gateway to advancing core knowledge?

Spelke's sweeping proposal requires greater precision in specifying the place of language in early cognition. We now know by 3 months of age, infants have already begun to forge a link between language and core cognition. This precocious link, which unfolds dynamically over development, may indeed offer an entry point for acquiring higher-order, abstract conceptual and representational capacities.

A Preliminary Longitudinal Study on Infant-Directed Speech (IDS) Components in the First Year of Life

Infant-directed speech (IDS) is an essential factor of mother–infant interaction and facilitates early language processing and word learning during dyadic interactions. This study aimed to longitudinally investigate emotional and prosodic components of IDS in the first year of life by analyzing children’s responses to the different prosodic trends that mothers use during the observation of mother–child interactions. Seventeen mothers and infants were recruited for this study during their first hospitalization. The study involved observing communication changes in face-to-face interactions between the mother and child at three, six, and nine months after the child’s birth. We analyzed the relationship between gaze direction, smiling, speech speed, and clarity. The results showed that the IDS differs in production when compared to the age of the child; at only nine months, there is high intensity. The same is evident from the results related to the elocution velocity. The verbal sensitivity of the mother and the ability to tune in to the affective states of the child, especially at nine months, can predict the child’s understanding of future language.

I See What You Are Saying: Hearing Infants’ Visual Attention and Social Engagement in Response to Spoken and Sign Language

Infants are endowed with a proclivity to acquire language, whether it is presented in the auditory or visual modality. Moreover, in the first months of life, listening to language supports fundamental cognitive capacities, including infants’ facility to form object categories (e.g., dogs and bottles). Recently, we have found that for English-acquiring infants as young as 4 months of age, this precocious interface between language and cognition is sufficiently broad to include not only their native spoken language (English), but also sign language (American Sign Language, ASL). In the current study, we take this work one step further, asking how “sign-naïve” infants—hearing infants with no prior exposure to sign language—deploy their attentional and social strategies in the context of episodes involving either spoken or sign language. We adopted a now-standard categorization task, presenting 4- to 6-month-old infants with a series of exemplars from a single category (e.g., dinosaurs). Each exemplar was introduced by a woman who appeared on the screen together with the object. What varied across conditions was whether this woman introduced the exemplar by speaking (English) or signing (ASL). We coded infants’ visual attentional strategies and their spontaneous vocalizations during this task. Infants’ division of attention and visual switches between the woman and exemplar varied as a function of language modality. In contrast, infants’ spontaneous vocalizations revealed similar patterns across languages. These results, which advance our understanding of how infants allocate attentional resources and engage with communicative partners across distinct modalities, have implications for specifying our theories of language acquisition.