The gestural repertoire and its evolution over the second year

The entire repertoire of communicative gestures was documented in a longitudinal, observational study of 10 infants, whose combined ages covered the range from 9 to 22 months. Early in the second year, giving as a request to do something with the object increased, while emotive gestures decreased. Later in the second year, pointing gestures increased, while protest gestures tended to decrease. Combining gestures with vocalization tended to increase only for protest gestures later in the second year. Eye contact showed a small but continuous increase in coordination with gestures over the second year, particularly with comment, request, and emotive gestures. These findings indicate an increasing use of the parent as an agent and of the informative function in non-verbal communication during this period of transition to verbal communication.     

A time series analysis of the relation between motor skill acquisition and sleep in infancy

To systematically examine the relation between motor milestone onset and disruption of night sleep in infancy, three families kept microgenetic, prospective, daily checklist diaries of their infants’ motor behavior and sleep (197-313 observation days; 19,000 diary entries). Process control and interrupted time series analyses examined whether deviations from the moving average for night wakings and evening sleep duration were temporally linked to motor skill onset and tested for meaningful differences in individual sleep patterns before and after skill onset. Model assumptions defined skill onset as first day of occurrence or as mastery and moving average windows as 3, 7, or 14 days. Changes in infants’ sleep patterns were associated with changing expertise for motor milestones. The temporal relation varied depending on infant and sleep parameter. Intensive longitudinal data collection may increase our understanding of micro-events in infant development.     

Cardiac physiological regulation across early infancy: The roles of infant surgency and parental involvement with mothers and fathers

High baseline respiratory sinus arrhythmia (RSA) and infant temperament are associated with a child’s ability to self-regulate, but moderators of this association have not been thoroughly examined in the literature. Parents who are more involved might have more opportunities to interact with and soothe their children. The current study examined whether parental involvement moderated the association between infant temperament and baseline RSA with mothers and fathers across early infancy. Participants included families (n = 91) assessed at 4 and 8 months of age. Infant temperamental surgency and parental involvement were measured via parent-report when infants were 4 months old, and infant baseline RSA was measured at 4 and 8 months of age. Results revealed differences in mother versus father predictors of infant baseline RSA. A significant Infant Surgency X Maternal Play interaction was revealed; infants of mothers who were low involvement increased in their baseline RSA as their surgency increased. A significant main effect of father care was found; infants with highly involved fathers had higher baseline RSA. In conclusion, mothers and fathers may differentially influence their infant’s cardiac physiological regulation based on their specific type of involvement.     

Words (but not tones) facilitate object categorization: evidence from 6- and 12-month-olds

Recent studies reveal that naming has powerful conceptual consequences within the first year of life. Naming distinct objects with the same word highlights commonalities among the objects and promotes object categorization. In the present experiment, we pursued the origin of this link by examining the influence of words and tones on object categorization in infants at 6 and 12 months. At both ages, infants hearing a novel word for a set of distinct objects successfully formed object categories; those hearing a sequence of tones for the same objects did not. These results support the view that infants are sensitive to powerful and increasingly nuanced links between linguistic and conceptual units very early in the process of lexical acquisition.     

Infant perception of audio-visual speech synchrony in familiar and unfamiliar fluent speech

We investigated the effects of linguistic experience and language familiarity on the perception of audio-visual (A-V) synchrony in fluent speech. In Experiment 1, we tested a group of monolingual Spanish- and Catalan-learning 8-month-old infants to a video clip of a person speaking Spanish. Following habituation to the audiovisually synchronous video, infants saw and heard desynchronized clips of the same video where the audio stream now preceded the video stream by 366, 500, or 666 ms. In Experiment 2, monolingual Catalan and Spanish infants were tested with a video clip of a person speaking English. Results indicated that in both experiments, infants detected a 666 and a 500 ms asynchrony. That is, their responsiveness to A-V synchrony was the same regardless of their specific linguistic experience or familiarity with the tested language. Compared to previous results from infant studies with isolated audiovisual syllables, these results show that infants are more sensitive to A-V temporal relations inherent in fluent speech. Furthermore, the absence of a language familiarity effect on the detection of A-V speech asynchrony at eight months of age is consistent with the broad perceptual tuning usually observed in infant response to linguistic input at this age.     

Individual and relational contributions to parallel and joint attention in infancy

Objective

This study examined the contributions of maternal bids for joint attention, relationship quality, and infant characteristics, to individual differences in infants’ parallel and joint attention.

Method

Fifty-two 10-month-olds and their mothers were assessed in order to investigate concurrent predictors of infant parallel attention, responding to joint attention, and initiating joint attention.

Results

Parallel attention was predicted by infants’ higher mental development, low expression of negative emotionality, and maternal entertaining behaviors. Responding to joint attention was marginally predicted by total maternal bids for joint attention. Initiating joint attention was predicted by the infants’ low expression of negative emotionality, as well as marginally predicted by fewer maternal teaching behaviors.

Conclusion

These results further the understanding of the factors influencing infant parallel as well as joint attention.     

Acquiring verbal reference: The interplay of cognitive,linguistic, and general learning capacities

Verbal reference is the ability to use language to communicate about objects, events, or ideas, even if they are not witnessed directly, such as past events or faraway places. It rests on a three-way link between words, their referents, and mental representations of those referents. A foundational human capacity, verbal reference extends the communicative power of language beyond the here-and-now, enabling access to language-mediated learning and thus fueling cognitive development. In the current review, we consider how and when verbal reference develops. The existing literature suggests that verbal reference emerges around infants’ first birthdays and becomes increasingly robust by their second. In discussing the powerful developmental advantages of acquiring verbal reference we propose that this achievement requires a dynamic interplay among infants’ cognitive and language development, fueled by general learning capacities. We close by describing new research directions, aimed at advancing our understanding of how verbal reference emerges.     

The social context of imitation in infancy

Infants increasingly generalize deferred imitation across environmental contexts between 6 and 18 months of age. In three experiments with 126 6-, 9-, 12-, 15-, and 18-month-olds, we examined the role of the social context in deferred imitation. One experimenter demonstrated target actions on a hand puppet, and a second experimenter tested imitation 24h later. When the second experimenter was novel, infants did not exhibit deferred imitation at any age; when infants were preexposed to the second experimenter, all of them did. Imitating immediately after the demonstration also facilitated deferred imitation in a novel social context at all ages but 6 months. Infants' pervasive failure to exhibit deferred imitation in a novel social context may reflect evolutionary selection pressures that favored conservative behavior in social animals.     

The "what" and "where" of object representations in infancy

Four-month-olds' memory for surface feature and location information was tested following brief occlusions. When the target objects were images of female faces or monochromatic asterisks infants showed increased looking times following a change in identity or color but not following a change in location or combinations of feature and location information. When the target objects were images of manipulable toys, the infants showed increased looking times following a change in location but not identity or the binding of location and identity information. This evidence is consistent with the idea that young infants are unable to maintain the information processed separately in both the dorsal and ventral visual streams during occlusions. Our results suggest that it is the target's affordance for action that determines whether the dorsal or ventral information is selectively maintained during occlusion.     

Basic-level category discriminations by 7- and 9-month-olds in an object examination task

This study examines 7- and 9-month-olds' ability to categorize cats as separate from dogs, and dogs as separate from cats in an object examination task. In Experiment 1, 7- and 9-month-olds (N = 30) familiarized with toy cat replicas were found to form a category of cat that included novel cats but excluded a dog and an eagle. In Experiment 2, 7- and 9-month-olds (N = 30) familiarized with toy dog replicas were found to form a category of dog that included a novel dogs and a novel cat but excluded an eagle. These results mirror those of 3- to 4-month-olds tested with visual preference methods and stand in contrast to previously reported object examination results. Analyses of the distribution of features in the exemplars used to familiarize infants suggest that, like the 3- to 4-month-olds, the 7- and 9-month-olds in these studies form categories within the task, and on the basis of feature distributions.