Languages instantiate many different kinds of dependencies, some holding between adjacent elements and others holding between nonadjacent elements. In the domain of phonology-phonotactics, sensitivity to adjacent dependencies has been found to appear between 6 and 10 months. However, no study has directly established the emergence of sensitivity…

It has long been thought that the prefrontal cortex, as the seat of most higher brain functions, is functionally silent during most of infancy. This review highlights recent work concerned with the precise mapping (localization) of brain activation in human infants, providing evidence that prefrontal cortex exhibits functional activation much…

The aim of this study was to examine the combined influences of infants' attention and use of social cues in the prediction of their language outcomes. This longitudinal study measured infants' visual attention on a distractibility task (11 months), joint attention (14 months), and language outcomes (word-object association, 14 months; MBCDI…

Toward the end of their first year of life, infants' overly specified word representations are thought to give way to more abstract ones, which helps them to better cope with variation not relevant to word identity (e.g., voice and affect). This developmental change may help infants process the ambient language more efficiently, thus enabling…

Four experiments investigated infants' preferences for age-appropriate and age-inappropriate infant-directed speech (IDS) over adult-directed speech (ADS). Two initial experiments showed that 6-, 10-, and 14-month-olds preferred IDS directed toward younger infants, and 4-, 8-, 10-, and 14-month-olds, but not 6-month-olds, preferred IDS directed…

This longitudinal study on Finnish families was conducted to identify developmental differences in family-level communication among mothers, fathers, and their infants during the second half of the infant's first year, and associations with infants' later language and communicative skills. We examined coregulated communication of parent-infant…

Although vocalization and mouthing are behaviors frequently performed by infants, little is known about the characteristics of vocalizations that occur with objects, hands, or fingers in infants' mouths. The purpose of this research was to investigate characteristics of vocalizations associated with mouthing in 6 to 9-month-old infants during play…

This study explored the impact of infant-directed speech (IDS) versus adult-directed speech (ADS) on neural activity to familiar and unfamiliar words in 6- and 13-month-old infants. Event-related potentials were recorded while infants listened to familiar words in IDS, familiar words in ADS, unfamiliar words in IDS, and unfamiliar words in ADS.…

We examined infants' recognition of functors and the accuracy of the representations that infants construct of the perceived word forms. Auditory stimuli were "Functor + Content Word" versus "Nonsense Functor + Content Word" sequences. Eight-, 11-, and 13-month-old infants heard both real functors and matched nonsense functors (prosodically…

The experiment reported here investigated infants' concept of intention, as well as the relation among intention understanding, general productive vocabulary, and internal state language production during the 2nd year. Results from an imitation task indicated that 18-month-olds are better able to differentiate between intentional and accidental…

We investigated the developmental trajectory of nonadjacent dependency learning in an artificial language. Infants were exposed to 1 of 2 artificial languages with utterances of the form [aXc or bXd] (Grammar 1) or [aXd or bXc] (Grammar 2). In both languages, the grammaticality of an utterance depended on the relation between the 1st and 3rd…