Preference for Dynamic Human Images and Gaze‐Following Abilities in Preterm Infants at 6 and 12 Months of Age: An Eye‐Tracking Study

Preterm children are reported to be at higher risk of social communication problems such as autism spectrum disorder compared with full‐term infants. Although previous studies have suggested that preference for social stimuli in infancy is a possible indicator of later social communication development, little is known about this relation in preterm infants. We examined the gaze behavior of low‐risk preterm and full‐term infants at 6 and 12 months' corrected ages using two types of eye‐tracking tasks, which measured 1) preference for social stimuli by biological motion and human geometric preference and 2) ability to follow another's gaze direction. We found that preterm (compared with full‐term) infants at both 6 and 12 months of age spent less time looking toward dynamic human images, followed another's gaze less frequently, and looked for a shorter time at an object cued by another. Moreover, we found a positive correlation between looking time toward dynamic human images and frequency of gaze following at 12 months of age in full‐term, but not preterm, infants. We discuss the relation between the atypical patterns of gaze behavior in preterm infants and their higher risk of later social communication problems.     

Separable Attentional Predictors of Language Outcome

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 vocabulary size and multi‐word productions at 18 months of age). Path analyses were conducted for two different language outcomes. The analysis for vocabulary revealed unique direct prediction from infants' visual attention on a distractibility task (i.e., maintaining attention to a target event in the presence of competing events) and joint attention (i.e., more frequent response to tester's bids for attention) for larger vocabulary size at outcome; this model accounted for 48% of variance in vocabulary, after controlling for baseline communication status (assessed at 11 months). The analysis for multi‐word productions yielded direct effects for infants' distractibility, but not joint attention; this model accounted for 45% of variance in multi‐word productions, again after controlling for baseline communication status. Indirect effects were not significant in either model. Results are discussed in light of the unique predictive role of attentional factors and social/attention cues for emerging language.     

Emotion regulation from infancy to toddlerhood: Individual and group trajectories of full-term and very-low-birthweight preterm infants

Adaptive emotion regulation begins with infants operating jointly with their parents to regulate their emotions, which fosters the development of independent regulation. Little is known about when or how this transition occurs, or the impact of factors such as parental availability or premature birth status. The current study examined the use of self-soothing, attentional distraction, and dyadic regulation in full-term and healthy very-low-birthweight (VLBW) preterm infant-mother dyads at 5 ½, 12, and 18 months of age. At 5 ½ months, dyads participated in the Still-Face procedure. At 12 and 18 months, dyads participated in two free-play interactions, a puzzle task, and an interference task. Emotion regulation behaviors were coded using two systematic, observational systems. Results indicated that infants used less self-soothing and attentional distraction and more dyadic regulation as they aged. Increased use of self-soothing at earlier ages predicted increased use of dyadic regulation at subsequent ages. Toddlers used more independent, attention-seeking, and escape behavior during periods of maternal unavailability. There were no significant differences between full-term and VLBW/preterm toddlers’ emotion regulation behaviors. Results from the current study contribute to the understanding of normative development of emotion regulation and the risk associated with prematurity.     

Temperamental Susceptibility to Parenting among Preterm and Full‐Term Infants in Early Cognitive Development

The current study examined the interaction between premature birth, temperamental reactivity, and parenting in early cognitive development. Participants were 142 infants (80 preterm; 62 full term) and their parents. Parent–child interactions (maternal, paternal, and co‐parental) were observed at age 6 months to assess parental structuring behaviors. Additionally, both parents reported on infants' temperamental reactivity. At 12 months of age, infants' cognitive abilities were assessed. Consistent with the diathesis–stress model, preterm infants had lower cognitive outcomes than full‐term infants when exposed to low levels of co‐parental structuring, but functioned similarly when exposed to high levels of co‐parental structuring. However, temperamental reactivity moderated this effect: Infants who carried one susceptibility factor (i.e., premature birth or reactive temperament) were similarly affected by co‐parental structuring, whereas infants who carried two or no susceptibility factors were not. Furthermore, consistent with the differential susceptibility hypothesis, infants with highly reactive temperaments had lower cognitive functioning when exposed to low maternal structuring, but higher cognitive functioning when exposed to high maternal structuring compared to infants with lower reactivity. Results from this study highlight the importance of considering both temperamental reactivity and quality of parenting in understanding preterm infants' early cognitive vulnerability.     

Early Segmentation Abilities in Preterm Infants

Infants born preterm have higher risks of developing linguistic deficits. Considering that the ability to segment words from fluent speech is crucial for lexical acquisition, Experiment 1 tested the ability of healthy extremely‐to‐late preterm infants to segment monosyllabic words at 6 months of postnatal age. Results establish basic segmentation skills in these infants. While we failed to find an effect of the degree of prematurity, this issue will need further exploration. Future studies will also have to specify the scope of these early segmentation skills, both in terms of the types of words segmented, the cues used to do so, and in terms of possible differences in performance between subgroups of preterm infants (e.g., based on gestational age or medical risks). Lastly, given that the preterm infants tested had a mean maturational age of 4 months, Experiment 2 explored monosyllabic segmentation in full‐term 4‐month olds. Infants succeeded at the task, providing the earliest developmental evidence of word segmentation in full‐term infants. These findings better specify the early trajectory of segmentation abilities in both full‐term and healthy, low‐risk preterm infants and support the proposal that prematurity might have a differential effect on the early acquisition of various linguistic levels.     

The Value of Vocalizing: 10‐Month‐Olds' Vocal Usage Relates to Language Outcomes at 15 Months

The interaction between infant's communicative competence and responsiveness of caregivers facilitates the transition from prelinguistic to linguistic communication. It is thus important to know how infants' communicative behavior changes in relation to different caregiver responses; furthermore, how infants' modification of communicative behavior relates to language outcomes. We investigated 39 10‐month‐old infants' communication as a function of mothers' attention and responses and the relationship to language outcomes at 15 months. We elicited infants' communicative behavior in three conditions: (1) joint attention: Mothers were visually attending and responding to infants' attention and interest; (2) available: Mothers were visually attending to infants, but not responding contingently to infants' attention and interest; (3) unavailable: Mothers were not attending to infants nor responding to them. Infants vocalized more when mothers attended and responded to them (conditions 1 and 2) than when mothers did not (condition 3), but infants' gesture and gesture‐vocal production did not differ across conditions. Furthermore, infants' production of a higher proportion of vocalizations in the unavailable condition relative to the joint attention condition correlated with, and predicted, infants' language scores at 15 months. Thus, infants who appear to be aware of the social effects of vocalizations may learn words better.     

Infants born full term and preterm increase the height of anti-gravity leg movements during a kick-activated mobile task using a scaffolded task environment

Prior research supports that infants born very preterm (PT), compared with full term (FT), have early differences in rate of learning and motor control that may hinder their ability to learn challenging motor tasks. Four-month-old infants born FT (n = 18) and PT (n = 18) participated in an infant kick-activated mobile task that was scaffolded to motivate progressively higher kicks. We found the FT group learned the association between their leg movements and mobile activation on the second day, but the PT group learned the association on the third day. Both groups of infants increased the height of their kicks on the day they learned the task, compared with their spontaneous kicking height. These findings suggest that infants born PT have the ability to learn challenging motor tasks, such as kicking high, when participating in a task environment that uses scaffolding.     

Infants’ abilities to respond to cues for joint attention vary by family socioeconomic status

The influence of socioeconomic variability on language and cognitive development is present from toddlerhood to adolescence and calls for investigating its earliest manifestation. Response to joint attention (RJA) abilities constitute a foundational developmental milestone that are associated with future language, cognitive, and social skills. How aspects of the family home environment shape RJA skills is relatively unknown. We investigated associations between family socioeconomic status (SES) —both parent education and family percentage of the federal poverty level (FPL)— parent depressive and anxiety symptoms and infant RJA performance in a cross-sectional sample of 173 infants aged 8–18 months and their parents from a variety of socioeconomic backgrounds. Results suggest that, correcting for age and receptive language, infants in families with greater economic resources respond to relatively less redundant, more sophisticated cues for joint attention. Although parent depressive and anxiety symptoms are negatively correlated with SES, parent depressive and anxiety symptoms were not associated with infant RJA. These findings provide evidence of SES-related differences in social cognitive development as early as infancy, calling on policymakers to address the inequities in the current socioeconomic landscape of the United States.     

Neural mechanisms of language development in infancy

Understanding the neural processes underpinning individual differences in early language development is of increasing interest, as it is known to vary in typical development and to be quite heterogeneous in neurodevelopmental conditions. However, few studies to date have tested whether early brain measures are indicative of the developmental trajectory of language, as opposed to language outcomes at specific ages. We combined recordings from two longitudinal studies, including typically developing infants without a family history of autism, and infants with increased likelihood of developing autism (infant-siblings) (N = 191). Electroencephalograms (EEG) were recorded at 6 months, and behavioral assessments at 6, 12, 18, 24 and 36 months of age. Using a growth curve model, we tested whether absolute EEG spectral power at 6 months was associated with concurrent language abilities, and developmental change in language between 6 and 36 months. We found evidence of an association between 6-month alpha-band power and concurrent, but not developmental change in, expressive language ability in both infant-siblings and control infants. The observed association between 6-month alpha-band power and 6-month expressive language was not moderated by group status, suggesting some continuity in neural mechanisms.     

Early social referencing predicts object mastery motivation in infancy: Social antecedents of object mastery motivation

The researchers sought to understand the typical development of social referencing and object mastery motivation in infancy and to determine the relationship between social referencing and object mastery behaviors in infants from 7 to 22 months of age. The study included 36 infants who were followed as part of a longitudinal study of at-risk infants but were not determined to need care in the neonatal intesive care unit at birth. Both mastery behaviors of persistence and success showed a statistically significant effect of age, while social behaviors remained stable from 7 to 22 months. Social behaviors at 7 and 10 months were correlated with persistence at 22 months and success at 16 to 22 months demonstrating that early social referencing predicts object mastery behaviors in later infancy. Further research should determine if this trend extends to early childhood.     

Home Environment,But Not Socioeconomic Status,is Linked to Differences in Early Phonetic Perception Ability

Infants perceptually tune to the phonemes of their native languages in the first year of life, thereby losing the ability to discriminate non‐native phonemes. Infants who perceptually tune earlier have been shown to develop stronger language skills later in childhood. We hypothesized that socioeconomic disparities, which have been associated with differences in the quality and quantity of language in the home, would contribute to individual differences in phonetic discrimination. Seventy‐five infants were assessed on measures of phonetic discrimination at 9 months, on the quality of the home environment at 15 months, and on language abilities at both ages. Phonetic discrimination did not vary according to socioeconomic status (SES), but was significantly associated with the quality of the home environment. This association persisted when controlling for 9‐month expressive language abilities, rendering it less likely that infants with better expressive language skills were simply engendering higher quality home interactions. This suggests that infants from linguistically richer home environments may be more tuned to their native language and therefore less able to discriminate non‐native contrasts at 9 months relative to infants whose home environments are less responsive. These findings indicate that home language environments may be more critical than SES in contributing to early language perception, with possible implications for language development more broadly.     

The Association Between Infants’ Attention Control and Social Inhibition is Moderated by Genetic and Environmental Risk for Anxiety

Infant social inhibition is associated with increased risk for anxiety later in life. Although both genetic and environmental factors are associated with anxiety, little empirical work has addressed how developing regulatory abilities work with genetic and environmental risk to exacerbate or mitigate problem behaviors. The current study was aimed at addressing this gap in research by investigating an early emerging regulatory behavior, attention control, in association with genetic and environmental risk for anxiety. Participants included 9‐month‐old adopted infants, their birth mothers, and adoptive parents (N = 361). Lifetime diagnosis of birth mother social phobia was obtained using structured interviews. Adoptive parents completed self‐report measures of anxiety symptoms. Infant social inhibition and attention control were coded during a stranger interaction and a barrier task, respectively. Neither adoptive nor birth parent anxiety was directly associated with social inhibition. The association of attention control with social inhibition in infants was moderated by birth and adoptive parent anxiety symptoms. When infants of birth mothers with social phobia were raised by adoptive parents with high self‐reported anxiety symptoms, greater attention control was associated with greater social inhibition. However, when raised by adoptive parents with low self‐reported anxiety, greater attention control was associated with less social inhibition.     

Responding to joint attention as a developmental catalyst: Longitudinal associations with language and social responsiveness

Joint attention (JA), infants' ability to engage in triadic attention with another person and a separate object or event, emerges in infancy. Responding to joint attention (RJA) develops earlier than initiating joint attention (IJA) and may benefit from a reconceptualization from a competence to a skill that varies in performance. Investigating associations between RJA performance and important skills of toddlerhood such as language, social responsiveness, and executive function (EF) in typically developing samples can better elucidate how RJA may serve as a developmental precursor to later dimensional skills, with implications for both typical and atypical development. Here, 210 (82% White) infants completed the Dimensional Joint Attention Assessment (DJAA), a naturalistic play-based assessment of RJA, at 8–15 months. At 16–38 months social responsiveness, verbal ability, and EF were assessed. Multilevel models showed that DJAA scores were associated with later verbal abilities and parent-reported social responsiveness. Exploratory analyses showed trend-level associations between RJA and EF. Results establish the content validity of the DJAA as a measure of RJA, and longitudinal associations with later verbal ability and social responsiveness. Future work should examine EF emergence and consolidation, and RJA and later EF associations.     

Predicting Individual Differences in Recall by Infants Born Preterm and Full Term

A heterogeneous sample of infants with preterm histories and infants born full term participated in a study of declarative memory and rate of encoding, as measured in an imitation task and an examining task, respectively. Here we report the comparisons of the performances of infants born very preterm (27–34 weeks gestation) and moderately preterm (35–37 weeks gestation) to infants born full term (38–41 weeks gestation) and tested at 12 months corrected age (from due date). Lower levels of recall were seen among the infants born very preterm. Rate of encoding, weeks gestation, and score on the Mental Development Index (MDI) of the Bayley Scales of Infant Development were tested as possible sources of individual differences in recall. Rate of encoding and MDI predicted delayed ordered recall. Implications for early detection of cognitive difficulties in children with preterm histories are discussed.     

The Developmental Course of Habituation in Infancy and Preschool Outcome

A longitudinal sample of 226 infants were tested monthly on habituation and novelty preference tasks, augmented with simultaneous heart rate recording from 3 to 9 months of age. Infants were then administered the Bayley Scales of Infant Development II (BSID) and MacArthur Communicative Development Inventory (MCDI) at 12, 18, and 24 months. Prior findings regarding the decline in look duration with age were replicated. Age‐based factors were extracted from the monthly assessments, an early attention factor from 3 to 6 months and a late attention factor from 7 to 9 months. A novelty preference factor, which grouped recognition performance at 4 and 6 months of age, was also derived. The late attention factor correlated negatively with a factor score derived from the BSID mental index, and the novelty preference aggregate was correlated positively with a factor score derived from the MCDI production scores. Two clusters of infants were derived based on the developmental course of change from the early attention to late attention look duration aggregates: One cluster (n= 150) decreased strongly, and another (n= 50) increased. Infants belonging to these clusters subsequently differed on both the BSID and MCDI outcomes, with the former cluster showing distinct advantages that increased as the outcome assessments progressed from 12 to 24 months of age. This finding was bolstered by subsequent analyses of data from infants who completed all tests run from 3 to 9 months. The results of this study suggest that the developmental course of attention during infancy is an important clue to cognitive and language outcomes in early childhood.     

Effects of Maternal Responsiveness on Infant Responsiveness and Behavior in the Still‐Face Task

The effects of maternal responsiveness on infant responsiveness and behavior in the Still‐Face Task were longitudinally examined through infants' first 3 months. Maternal vocal responsiveness and infant vocal and smiling responsiveness significantly increased when infants were 2 months of age. Mothers showed continuity of individual differences in vocal responsiveness from the infants' newborn period. Maternal responsiveness predicted infant responsiveness within and across sessions. Compared with infants with low‐responsive mothers, infants with high‐responsive mothers were more attentive and affectively engaged during the Still‐Face Task from 1 month of age. Infants with high‐responsive mothers discriminated between the task phases with their smiling at 1 month, a month before infants with low‐responsive mothers did so. Infants in both groups discriminated between the phases with their attention and nondistress vocalizations throughout their first 3 months. Results suggest that maternal responsiveness influences infant responsiveness and facilitates infants' engagement and expectations for social interaction.     

Clinically depressed and typically developing mother–infant dyads: Domain base rates and correspondences,relationship contingencies and attunement

Maternal depression is associated with adverse outcomes in infants. Unfavorable parenting practices likely constitute one pathway of risk transmission from mother to infant, but definitional and methodological variation in the extant literature precludes a comprehensive or conclusive understanding of potential underlying mechanisms. This study aimed to illuminate the role of maternal clinical depression in mother–infant interaction by turning a microanalytic lens on four substantive relationship issues: base rates, correspondences, contingencies, and attunement. Several maternal parenting practices (aggregated into social, didactic, and language domains) and several infant behaviors (aggregated into social, exploration, and non-distress vocalization domains) were microcoded to 0.10 s from naturalistic hour long interactions of clinically depressed mothers (n = 60) and matched non-depressed controls (n = 60) with their 5-month-olds. Clinically depressed mothers spontaneously engaged their infants less didactically, were less contingent to their infants in social, didactic, and language domains, and were less attuned with their infants than were non-depressed mothers. Infants of clinically depressed mothers vocalized non-distress less than infants of non-depressed mothers. These differences unveil key disadvantages in the everyday lived experiences of infants of clinically depressed mothers. The findings advance understanding of maternal depression and its effects and have implications for identifying infants at risk on account of their mothers’ clinical depression.     

Maternal input and infants’ response to infant‐directed speech

Caregivers typically use an exaggerated speech register known as infant‐directed speech (IDS) in communication with infants. Infants prefer IDS over adult‐directed speech (ADS) and IDS is functionally relevant in infant‐directed communication. We examined interactions among maternal IDS quality, infants’ preference for IDS over ADS, and the functional relevance of IDS at 6 and 13 months. While 6‐month‐olds showed a preference for IDS over ADS, 13‐month‐olds did not. Differences in gaze following behavior triggered by speech register (IDS vs. ADS) were found in both age groups. The degree of infants’ preference for IDS (relative to ADS) was linked to the quality of maternal IDS infants were exposed to. No such relationship was found between gaze following behavior and maternal IDS quality and infants’ IDS preference. The results speak to a dynamic interaction between infants’ preference for different kinds of social signals and the social cues available to them.     

Contrasts in Infant Classical Eyeblink Conditioning as a Function of Premature Birth

The impact of premature birth on associative learning was evaluated using simple delay eyeblink conditioning in which a tone conditional stimulus was paired with an air puff unconditional stimulus. Fourteen preterm (28–31 weeks gestation) and 11 full‐term infants completed at least 3 conditioning sessions, 1 week apart, at 5 months of age (corrected age). Preterm and full‐term groups demonstrated associative learning, as confirmed by comparison with an unpaired control group. Preterm infants, however, exhibited more variability in their learning rates. The majority of full‐term infants and half the preterm infants exhibited rapid acquisition and gradual extinction of conditional responding. A greater proportion of preterm than full‐term infants failed to acquire conditional responding within 2 training sessions. Differences in associative learning rates were not the result of differences in arousal or attentional processes. Diversity in acquisition rates exposed an increased risk for disrupted infant learning due to premature birth.     

Intention or Attention Before Pointing: Do Infants’ Early Holdout Gestures Reflect Evidence of a Declarative Motive?

Gestures are the first signs of intentional communication within prelinguistic infants and can reflect various motives, including a declarative motive to share attention and interest. The ability to use gestures declaratively has been linked to later language development; therefore, it is important to understand the origins of this motive. Previous research has focused on the use of declarative pointing at around 12 months; however, other potential forms of declarative communication, such as holdout gestures, are yet to be studied in detail. The purpose of this study was to examine whether from 10 months, infants use holdouts declaratively. We elicited holdouts from 36 infants and then reacted to these gestures in four different conditions: (1) joint attention: shared interest; (2) infant attention: attended to infant; (3) toy attention: attended to toy; (4) ignore: gesture was not attended to. Infants’ behavioral responses were recorded. When the experimenter engaged in joint attention, infants were significantly more likely to display a positive attitude and produced fewer re‐engagement attempts. In contrast, the three non‐joint attention conditions displayed significantly higher negative attitudes and attempts to re‐engage the experimenter. We conclude that infants display declarative communication prior to 12 months, resetting the age at which these more complex skills emerge.