The temporal coordination of early infant communication

The ability to coordinate expressive behaviors is crucial to the development of social and emotional communication. Coordination involves systematic sequencing of behaviors from two different modalities that have some temporal overlap. A bootstrapping procedure was used to determine whether preverbal 3- and 6-month-old infants sequence vocalizations, gazes at their mothers' faces, and facial expressions into pairs of coordinated patterns nonrandomly. Smiles and frowns were highly coordinated with vocalizations. Smiles were also coordinated with gazes at mothers' faces, which became stronger with age. Vocalizations were not coordinated with gazes at mothers' faces. These findings illustrate the manner in which infants temporally coordinate communicative actions and provide new evidence that facial expressions (particularly smiles) are central to early infant communications.     

Synchrony in mother-infant vocal interactions revealed through timed event sequences

This report extends a previous cross-cultural study of synchrony in mother-infant vocal interactions (Bornstein et al., 2015) to immigrant samples. Immigrant dyads from three cultures of origin (Japan, South Korea, South America) living in the same culture of destination (the United States) were compared to nonmigrant dyads in those same cultures of origin and to nonmigrant European American dyads living in the same culture of destination (the United States). This article highlights an underutilized analysis to assess synchrony in mother-infant interaction and extends cross-cultural research on mother-infant vocal interaction. Timing of onsets and offsets of maternal speech to infants and infant nondistress vocalizations were coded separately from 50-min recorded naturalistic observations of mothers and infants. Odds ratios were computed to analyze synchrony in mother-infant vocal interactions. Synchrony was analyzed in three ways -- contingency of timed event sequences, mean differences in contingency by acculturation level and within dyads, and coordination of responsiveness within dyads. Immigrant mothers were contingently responsive to their infants’ vocalizations, but only Korean immigrant infants were contingently responsive to their mothers’ vocalizations. For the Japanese and South American comparisons, immigrant mothers were more contingently responsive than their infants (but not robustly so for South American immigrants). For the Korean comparison, mean differences in contingent responsiveness were found among acculturation groups (culture of origin, immigrant, culture of destination), but not between mothers and infants. Immigrant dyads’ mean levels of responsiveness did not differ. Immigrant mothers’ and infants’ levels of responsiveness were coordinated. Strengths and flexibility of the timed event sequential analytic approach to assessing synchrony in mother-infant interactions are discussed, particularly for culturally diverse samples.     

Co‐occurences of preverbal vocal behavior and motor action in early infancy

This study reports on co‐occurrence of vocal behaviors and motor actions in infants in the prelinguistic stage. Four Japanese infants were studied longitudinally from the age of 6 months to 11 months. For all the infants, a 40 min sample was coded for each monthly period. The vocalizations produced by the infants co‐occurred with their rhythmic actions with high frequency, particularly in the period preceding the onset of canonical babbling. Acoustical analysis was conducted on the vocalizations recorded before and after the period when co‐occurrence took place most frequently. Among the vocalizations recorded in the period when co‐occurrence appeared most frequently, those that co‐occurred with rhythmic action had significantly shorter syllable duration and shorter formant‐frequency transition duration compared with those that did not co‐occur with rhythmic action. The rapid transitions and short syllables were similar to patterns of duration found in mature speech. The acoustic features remained even after co‐occurrence disappeared. These findings suggest that co‐occurrence of rhythmic action and vocal behavior may contribute to the infant’s acquisition of the ability to perform the rapid glottal and articulatory movements that are indispensable for spoken language acquisition.     

Effects of multilingualism on Australian infants’ language environments in early childhood education centers

This study investigates differences in the language environments experienced by multilingual and monolingual infants in early childhood education and care (ECEC) settings. The Language Environment Analysis (LENA) technology was used to collect day-long audio-recordings from 181 one-year-old infants (age range from 12 to 21 months). We examined whether infants’ multilingual status predicts the amount of educators’ language input (adult word count, AWC), child vocalizations (CVC) and conversational turns (CTC), as well as interaction effects on AWC, CVC and CTC of infants’ multilingual status and other infant, home and ECEC characteristics. Multilevel mixed effects models revealed no main effect of infants’ multilingual status on the language environment outcome variables. Instead, infant gender significantly predicted adult word count, with female infants hearing more words from educators than male infants. There was a significant interaction effect between the infants’ multilingual status and both their age and length of time in an ECEC setting on child vocalizations. While monolingual infants produced more vocalizations as their age increased, multilingual infants did not show this increase in vocalizations with age. Further, the difference between monolingual and multilingual children’s vocalizations decreased as the length of time in ECEC increased. There were no significant predictors of conversational turns. Findings from this study suggest that early childhood educators do not adjust their talk according to the multilingual status of the infants. However, multilingual infants do not increase their vocalizations as their age increases to the same extent as do their monolingual peers. The interaction effect between multilingualism and the length of ECEC attendance also implies that ECEC environments may be particularly beneficial for supporting multilingual infants’ vocalizations. This study highlights the need to provide pedagogical support to educators to help them to encourage multilingual infants’ vocalizations in ECEC settings.     

Do Questions Get Infants Talking? Infant Vocal Responses to Questions and Declaratives in Maternal Speech

Maternal questions play a crucial role in early language acquisition by virtue of their special grammatical, prosodic and lexical forms, and their abundance in the input. Infants are able to discriminate questions from other sentence types and produce rising intonations in their own requests. This study examined whether caregiver questions were related to the quantity of infant vocalizations. Thirty‐six infants aged 10 and 14 months participated in a laboratory play session with their mothers. In separate blocks, mothers were instructed to ask questions and to refrain from asking questions. Both block‐level and utterance‐level analyses found no evidence that maternal questions affected the amount of infant‐response vocalizations. Mothers of 14‐month‐olds (but not 10‐month‐olds) tended to repeat questions. Copyright © 2016 John Wiley & Sons, Ltd.     

Infants’ intentionally communicative vocalizations elicit responses from caregivers and are the best predictors of the transition to language: A longitudinal investigation of infants’ vocalizations,gestures and word production

What aspects of infants’ prelinguistic communication are most valuable for learning to speak, and why? We test whether early vocalizations and gestures drive the transition to word use because, in addition to indicating motoric readiness, they (a) are early instances of intentional communication and (b) elicit verbal responses from caregivers. In study 1, 11 month olds (N = 134) were observed to coordinate vocalizations and gestures with gaze to their caregiver's face at above chance rates, indicating that they are plausibly intentionally communicative. Study 2 tested whether those infant communicative acts that were gaze‐coordinated best predicted later expressive vocabulary. We report a novel procedure for predicting vocabulary via multi‐model inference over a comprehensive set of infant behaviours produced at 11 and 12 months (n = 58). This makes it possible to establish the relative predictive value of different behaviours that are hierarchically organized by level of granularity. Gaze‐coordinated vocalizations were the most valuable predictors of expressive vocabulary size up to 24 months. Study 3 established that caregivers were more likely to respond to gaze‐coordinated behaviours. Moreover, the dyadic combination of infant gaze‐coordinated vocalization and caregiver response was by far the best predictor of later vocabulary size. We conclude that practice with prelinguistic intentional communication facilitates the leap to symbol use. Learning is optimized when caregivers respond to intentional vocalizations with appropriate language.     

Toddlers’ affective responses to sociomoral scenes: Insights from physiological measures

A growing literature suggests that preverbal infants are sensitive to sociomoral scenes and prefer prosocial agents over antisocial agents. It remains unclear, however, whether and how emotional processes are implicated in infants’ responses to prosocial/antisocial actions. Although a recent study found that infants and toddlers showed more positive facial expressions after viewing helping (vs. hindering) events, these findings were based on naïve coder ratings of facial activity; furthermore, effect sizes were small. The current studies examined 18- and 24-month-old toddlers’ real-time reactivity to helping and hindering interactions using three physiological measures of emotion-related processes. At 18 months, activity in facial musculature involved in smiling/frowning was explored via facial electromyography (EMG). At 24 months, stress (sweat) was explored via electrodermal activity (EDA). At both ages, arousal was explored via pupillometry. Behaviorally, infants showed no preferences for the helper over the hinderer across age groups. EMG analyses revealed that 18-month-olds showed higher corrugator activity (more frowning) during hindering (vs. helping) actions, followed by lower corrugator activity (less frowning) after hindering (vs. helping) actions finished. These findings suggest that antisocial actions elicited negativity, perhaps followed by brief disengagement. EDA analyses revealed no significant event-related differences. Pupillometry analyses revealed that both 18- and 24-month-olds’ pupils were smaller after viewing hindering (vs. helping), replicating recent evidence with 5-month-olds and suggesting that toddlers also show less arousal following hindering than following helping. Together, these results provide new evidence with respect to whether and how arousal/affective processes are involved when infants process sociomoral scenarios.     

The Effect of Maternal Depressed Mood on Infant Emotional Reaction in a Surprise‐Eliciting Situation

The purpose of this study is to examine the claim that an infant's ability to respond appropriately to an emotional situation varies according to the emotional state of the mother. Surprise expressions in mother and child were examined both in terms of paralinguistic aspects of surprise vocalizations as well as facial expressions. Seventy‐two infants and their mothers (mean age=8 months, range=5–11 months) were video‐ and audiotaped in their homes. Half of the infants, matched for age and gender, had mothers who reported depressed mood. Infants of mothers with depressed mood showed significantly fewer components of facial expressions of surprise compared with infants of nondepressed mothers. Mothers with depressed mood exclaimed surprise with a significantly lower pitch (mean F₀=386.13 Hz ) compared to nondepressed mothers (mean F₀=438.10 Hz ). Furthermore, mothers with depressed mood showed fewer associations between elements of emotional expression than the nondepressed group. Infants' expressions of surprise are influenced by maternal mood, resulting in reduced expression of the emotion in infants of mothers with depressed mood. These results are discussed in terms of coordination of vocal parameters in mother–infant dyadic interaction.     

Infant-adult vocal interaction dynamics depend on infant vocal type,child-directedness of adult speech,and timeframe

This study explored the temporal contingencies between infant and adult vocalizations as a function of the type of infant vocalization, whether adult caregivers’ vocalizations were infant-directed or other-directed, and the timescale of analysis. We analyzed excerpts taken from day-long home audio recordings that were collected from nineteen 12- to 13-month-old American infants and their caregivers using the LENA system. Three 5-minute sections having high child vocalization rates were identified within each recording and coded by trained researchers. Infant and adult vocalizations were sequenced and defined as contingent if they occurred within 1 s, 2 s, or 5 s of each other. When using 1 s or 2 s definitions of temporal adjacency, infant vocalizations generally predicted subsequent infant-directed adult vocalizations. A reflexive vocalization (i.e. a cry or a laugh) was the strongest predictor. Likewise, within 1–2 s timeframes, infant-directed adult speech generally predicted infant vocalizations with reflexive vocalizations being particularly predictive. Infant vocalizations predicted fewer subsequent other-directed adult vocalizations and were less likely following other-directed adult vocalizations when considering up to 5 s lags. This suggests an understudied communicative role for infants of non-infant-directed adult speech. These results demonstrate the importance of timescale in studying infant-adult interactions, support the communicative significance of reflexive infant vocalizations and other-directed adult speech in addition to more commonly studied vocalization types, and highlight the challenges of determining direction(s) of influence when using only two-event sequences.     

Categorizing coordination from the perception of joint actions

The ability to perceive others’ actions and coordinate our own body movements accordingly is essential for humans to interact with the social world. However, it is still unclear how the visual system achieves the remarkable feat of identifying temporally coordinated joint actions between individuals. Specifically, do humans rely on certain visual features of coordinated movements to facilitate the detection of meaningful interactivity? To address this question, participants viewed short video sequences of two actors performing different joint actions, such as handshakes, high fives, etc. Temporal misalignments were introduced to shift one actor’s movements forward or backward in time relative to the partner actor. Participants rated the degree of interactivity for the temporally shifted joint actions. The impact of temporal offsets on human interactivity ratings varied for different types of joint actions. Based on human rating distributions, we used a probabilistic cluster model to infer latent categories, each revealing shared characteristics of coordinated movements among sets of joint actions. Further analysis on the clustered structure suggested that global motion synchrony, spatial proximity between actors, and highly salient moments of interpersonal coordination are critical features that impact judgments of interactivity.     

Social regulatory effects of infant nondistress vocalization on maternal behavior

This study investigated the social regulatory function of infant nondistress vocalization in modulating maternal response. Thirteen infants and their mothers were observed weekly in a face-to-face interaction situation from 4 to 24 weeks. After the occurrences and the speech quality of infant nondistress vocalization were identified, maternal contingent responses to these vocalizations were also coded. Each responsive action was further classified by the change processes involved. Results showed that it was the occurrence of infant nondistress vocalization rather than its speech quality that regulated maternal verbal response concurrently and that infant nondistress vocalization was more likely to be synchronized with maternal facial expression and touch than with head movements. Developmentally, significant individual differences were found in the linear growth patterns of overall maternal response and within the individual modalities when responding to speechlike vocalizations.     

THREE-MONTH-OLD INFANTS CAN LEARN TASK-SPECIFIC PATTERNS OF INTERLIMB COORDINATION

Three-month-old infants cannot yet coordinate and control their limbs for functional tasks like reaching or locomoting This study demonstrates that given an appropriate, novel task, infants can transform their seemingly spontaneous kicking movements into new and efficient patterns of interlimb coordination even at this early age Three-month-old infants were allowed to control the movement of an overhead mobile by means of a string attached to their left ankles In addition, some groups had their two legs yoked together at the ankle with a soft elastic The elastic permitted kicks to be coordinated in any pattern—alternating, single, or simultaneous—but simultaneous kicks provided the most vigorous activation of the mobile All infants kicked more and faster when their kicks were reinforced by mobile movement than when their kicks did not activate the mobile However, only the yoked infants increasingly moved their legs in a simultaneous, or in-phase, pattern The study suggests that learning processes are in place at 3 months for infants to discover a match between their interlimb coordination patterns and a specific task, and that these learning processes, rather than autonomous brain "maturation," may underlie the acquisition of motor skills     

Face the noise: embodied responses to nonverbal vocalizations of discrete emotions

Extensive prior research has shown that the perception of an emotional facial expression automatically elicits a corresponding facial expression in the observer. Theories of embodied emotion, however, suggest that such reactions might also occur across expressive channels, because simulation is based on integrated motoric and affective representations of that emotion. In the present studies, we examined this idea by focusing on facial and experiential reactions to nonverbal emotion vocalizations. In Studies 1 and 2, we showed that both hearing and reproducing vocalizations of anger, disgust, happiness, and sadness resulted in specific facial behaviors, as well as congruent self-reported emotions (Study 2). In Studies 3 and 4, we showed that the inhibition of congruent facial actions impaired listeners' processing of emotion vocalizations (Study 3), as well as their experiences of a concordant subjective state (Study 4). Results support the idea that cross-channel simulations of others' states serve facilitative functions similar to more strict imitations of observed expressive behavior, suggesting flexibility in the motoric and affective systems involved in emotion processing and interpersonal emotion transfer. We discuss implications for embodiment research and the social consequences of expressing and matching emotions across nonverbal channels.     

Infants' responses to mothers' imitative behaviors

Several investigators have suggested that young infants' smiles and vocalizations following their mothers' imitative behaviors might reflect infant recognition that the mother's behavior is imitative or at least contingent. This study investigated whether infants smile and vocalize more frequently subsequent to maternal imitative than non-imitative behavior during both spontaneous and imitative face-to-face interactions. Fourteen 3 1/2-month-old infants and their mothers were videotaped in these two face-to-face interaction situations. The infants vocalized more frequently during the imitative situation and infant vocalizations plus simultaneous smiling, and vocalizations occurred more often following maternal imitative than non-imitative behavior. Although these data suggest that infant vocalizations and simultaneous smiles and vocalizations may reflect the infants' recognition of maternal imitative behavior, they do not establish definitively that it is the imitation per se vs. the contingency aspect that is recognized by the infant.     

Depressed mothers' and their infants' interactions with nondepressed partners

Twenty depressed adolescent mothers were videotaped interacting with their own infant and with the infant of a nondepressed mother. In addition, nondepressed mothers were videotaped with their own infant as well as with the infant of a depressed mother. Depressed mothers showed less facial expressivity than nondepressed mothers and received less optimal interaction rating scale scores (a summary score for state, physical activity, head orientation, gaze, silence during gaze aversion, facial expressions, vocalizations, infantized behavior, contingent responsivity, and gameplaying). This occurred independent of whether they were interacting with their own infant versus an infant of a nondepressed mother, suggesting that depressed mothers display less optimal behaviors to infants in general. The infants of both depressed and nondepressed mothers received better head orientation and summary ratings when they were interacting with another mother, perhaps because the other mother was more novel. Infants of nondepressed mothers, in particular, had better summary ratings (state, physical activity, head orientation, gaze, facial expressions, fussiness, and vocalizations) than the infants of depressed mothers when interacting with depressed mothers. Thus, it may be that infants of nondepressed mothers are generally better interaction partners than infants of depressed mothers. Another related possibility is that they persist longer in trying to elicit a response from mothers less responsive than their own, given that they have learned to expect a response to their behavior.     

Reinforcement of vocalizations through contingent vocal imitation

Maternal vocal imitation of infant vocalizations is highly prevalent during face-to-face interactions of infants and their caregivers. Although maternal vocal imitation has been associated with later verbal development, its potentially reinforcing effect on infant vocalizations has not been explored experimentally. This study examined the reinforcing effect of maternal vocal imitation of infant vocalizations using a reversal probe BAB design. Eleven 3- to 8-month-old infants at high risk for developmental delays experienced contingent maternal vocal imitation during reinforcement conditions. Differential reinforcement of other behavior served as the control condition. The behavior of 10 infants showed evidence of a reinforcement effect. Results indicated that vocal imitations can serve to reinforce early infant vocalizations.     

The social environments of early infancy in Japan and the United States

The social environments of early infancy in Japan and the United States were compared in terms of the context of caregiving and the quality of the month-infant interaction. Mothers of 17 Japanese infants and 17 infants in the United States were interviewed in their homes about the experiences that they provided for their 4-month-old infants, and mother-infant interactions were recorded on videotape. Levels of parents' education were similar in both countries. The context of the infant's development varied substantially with culture. Mothers in the United States provided a greater variety of experiences on the HOME and care of Japanese infants tended to be more exclusively provided by mothers whereas care of infants in the United States was shared by fathers and other caregivers to a greater extent. Examination of behaviour frequencies during mother-infant interaction indicated that mothers in Japan provided their infants with more vocal input and more physical play than mothers in the United States and Japanese mothers were more vocally responsive to their infants' vocalizations.     

Infants’ expressive behaviors to mothers and unfamiliar partners during face-to-face interactions from 4 to 10 months

Changes in the organization of infant looking, facial expressions, and vocalizations were examined over age (4, 7, and 10 months) and with different social partners. Although infants at all ages accompanied smiling with looking at both mothers and unfamiliar partners, 7- and 10-month infants accompanied vocalization with looking only when they were with mothers. Seven- and 10-month-olds vocalized with unfamiliar partners only when they were smiling at the same time. When mothers stopped talking, infants reduced smiling significantly at all ages, yet vocalized more at 10 months. In the second half of the first year, there are fundamental changes in the coordination of infant expressive behaviors that reveal a keen attunement to variations in maternal behavior and the familiarity of social partners.     

Learning how to learn from social feedback: The origins of early vocal development

Infants’ prelinguistic vocalizations reliably organize vocal turn-taking with social partners, creating opportunities for learning to produce the sound patterns of the ambient language. This social feedback loop supporting early vocal learning is well-documented, but its developmental origins have yet to be addressed. When do infants learn that their non-cry vocalizations influence others? To test developmental changes in infant vocal learning, we assessed the vocalizations of 2- and 5-month-old infants in a still-face interaction with an unfamiliar adult. During the still-face, infants who have learned the social efficacy of vocalizing increase their babbling rate. In addition, to assess the expectations for social responsiveness that infants build from their everyday experience, we recorded caregiver responsiveness to their infants’ vocalizations during unstructured play. During the still-face, only 5-month-old infants showed an increase in vocalizing (a vocal extinction burst) indicating that they had learned to expect adult responses to their vocalizations. Caregiver responsiveness predicted the magnitude of the vocal extinction burst for 5-month-olds. Because 5-month-olds show a vocal extinction burst with unfamiliar adults, they must have generalized the social efficacy of their vocalizations beyond their familiar caregiver. Caregiver responsiveness to infant vocalizations during unstructured play was similar for 2- and 5-month-olds. Infants thus learn the social efficacy of their vocalizations between 2 and 5 months of age. During this time, infants build associations between their own non-cry sounds and the reactions of adults, which allows learning of the instrumental value of vocalizing.