Infants' emerging sense of agency is thought to be supported by caregivers' contingent responsiveness. However, it remains unclear which types of responses are most relevant to this process. Here, we examined the role of contingent vocal imitation, defined as the prompt repetition of an infant's vocalization by an interaction partner. To tease apart the contribution of contingent vocal imitation from other elements of social interactions, we developed a novel vocal contingency paradigm. First, we investigated whether 5- to 6-month-old infants could rapidly learn the contingency between their own vocalizing and a novel imitative response. Then, we examined whether infants tested this newly learned contingency when it was suddenly discontinued. Novel audio-visual imitative responses were delivered and manipulated by an artificial agent. Infants' vocalizations were recorded while they experienced the novel contingency (connect phase) and its discontinuation (disconnect phase). Time-course analyses indicated a significant linear increase in vocalization frequency over time in the connect phase, supporting the hypothesis that contingent vocal imitation enables rapid vocal contingency learning. Descriptively, data suggested a quadratic trend consistent with a vocal extinction burst during the disconnect phase. However, this trend did not reach statistical significance. Therefore, there was only partial support for the role of contingent vocal imitation in the emerging sense of agency (i.e., young infants quickly learned this contingency, but there was no evidence that they tested it upon discontinuation). Overall, our paradigm provided proof of concept that vocal contingency learning can be studied in the absence of a human interaction partner.
Inferring the goals of other people's actions is an important aspect of early social cognitive development. Using an experimental manipulation, we investigated the role of infant motor processes in the processing of action they see performed by another person. We designed a procedure in which we inhibited infants' concurrent access to motor representations of precision grasping as they observed the reach-to-grasp action of an adult experimenter. In a within-subjects design, 48 12-month-olds watched adult reach-to-grasp actions under two conditions of hand posture in randomly-assigned order: (a) hands free and (b) hands constrained in a manner that blocked their grip formation. Infant looking times were measured as an experimenter reached toward large and small objects, using a power or precision grip type. Infants' prior-existing fine motor skills were assessed using a standardized parental report questionnaire. Results showed that infant looking times varied as a function of the interaction between infants' existing fine motor skill and their experimentally-manipulated access to motor representations of the action (p = 0.017). The better an infant's fine motor skills, the greater the reduction in their looking to the object congruent with the actor's grip type under the motor interference induced by hand constraint. This effect was particularly pronounced during the precision grip trials (p = 0.032). These findings advance our understanding of the role that infants' self-experience plays in the processing of the manual actions of others. More generally, such results inform theories about the functional significance of action perception-production links in early human development.
Conversations with caregivers scaffold infant language development. The importance of conversational turn-taking is widely demonstrated in dyadic interactions, particularly in home environments. Less is understood about the dynamics of conversational turns in polyadic classroom environments where educators are responsible for facilitating conversations with multiple young conversational partners. This study used a microanalytical approach to examine conversations during ten-minute recordings from 29 infants sampled from a subset of hour-long videos of infants in early childhood education centers in Sydney, Australia. We examined the qualities of conversations beyond simple adult contingency to focus on both temporal and semantically aligned responses to infants' cues. The characteristics of conversational turns were then decomposed to explore how the likelihood of conversation changes as a function of infant vocal cues, caregiver response patterns, and the number of children present. Infants actively shaped their conversations with educators by directing their vocalizations to capture educators' attention. Directed vocalizations (educator-directed, object-directed) were more likely to receive a response than undirected vocalizations, and more speech-like vocalizations received higher response rates than immature vocalizations. Contingency rates varied across infants, but most responses to infant vocalizations were semantically contingent, regardless of who initiated the conversation. Educator-initiated conversations predicted longer turns than infant-initiated conversations. However, group size did not relate to the length of conversations. Educators were skilled at facilitating multi-turn conversations despite frequent polyadic interactions. The findings enhance understanding of the moment-to-moment interactions that shape language development and highlight characteristics of supportive language environments in classroom settings.
In-person co-play between infants and adults develops rapidly during infancy, but little research has examined how families play together over video chat. Research demonstrates that video chat may support family connections, especially with grandparents and other family members separated by physical location. However, video chat interactions also place significant socio-cognitive demands on infants that may impact the frequency and variety of family play. The present study examines predictors of intergenerational virtual play compared to in-person play. We conducted an OSF pre-registered secondary analysis of data from a longitudinal study of 47 infant-parent-grandparent triads who recorded up to three naturalistic Zoom video chats and a session when they met in person. All instances of attempted infant-grandparent play were coded for playful activity type (e.g., dancing, hide & seek), duration, and whether the infant was successfully engaged in play (e.g., responded by smiling, vocalizing or imitating). Descriptive analyses revealed variability in play between families and across sessions. To capture the variety of ways in which grandparents, parents and infants played together, we fit growth models to predict the frequency of play bouts, the number of different types of playful activities observed (play repertoire), the proportion of time engaged in play, the proportion of play bouts for which infants were positively engaged, and the proportion of play bouts initiated by infants during video chat sessions. Across analyses, age was the strongest predictor of infant play on video chat. We then compared video chat play to play during the in-person session and found that play repertoire was significantly greater on video chat than in person. This study highlights the potential of digital tools to enhance intergenerational family relationships and social interactions through play. Video chat may serve as a high-quality supplemental activity for separated families.
Post-encoding sleep facilitates memory consolidation from early infancy. Learning from digital content might also benefit from post-encoding sleep. However, infants find it more difficult to learn and remember screen content (transfer deficit) and may only recognize its relevance when scaffolded by caregivers. We investigated infants' memory performance as a function of presentation mode (live or video), post-encoding sleep, and caregiver scaffolding with the aim of replicating the transfer deficit and the beneficial effect of a post-encoding nap. We expected the nap benefit to be less pronounced when information was encoded from videos. We compared data from a live (n = 68) and a video experiment (n = 69). In both experiments, 15- and 24-month-olds watched demonstrations of two deferred imitation tasks (live or on prerecorded video). During one of the demonstrations, caregivers scaffolded the task. Half of the infants in each age-group napped for ≥ 30 min after demonstration, whereas the others remained awake for ≥ 4 h. Memory performance was assessed after 24 h counting the reproduced target actions. Contrary to expectations, the nap benefit did not replicate in the live demonstration sample. However, when both samples were examined together there was a main effect of nap condition showing that infants who had napped retrieved more target actions than awake infants. Moreover, cross-experiment comparisons revealed a transfer deficit and an unexpected disruptive effect of caregiver scaffolding on memory performance in 15-month-olds. Results are discussed in light of limits on detecting sleep-mediated memory effects and the challenges of remembering digital information in infancy due to cognitive load.
Maternal responsiveness to infant bids for attention predicts a variety of child outcomes including language, social-emotional, and cognitive functioning. Recently, a study demonstrated that greater maternal redirection (but not acceptance) of infant bids for attention predicted lower distractibility and, in turn, better receptive language outcomes in infants. To learn more about the potential basis for these relations, the current study took an in-depth look at differences in mother-infant dyadic behaviors as a function of whether mothers responded to infant bids for attention by redirecting versus accepting bids. We examined differences in infant gaze, mother-infant dyadic gaze, maternal multimodality (combining gaze, touch, and vocalizing), and maternal response speed. When infants (N = 67) were 12 months of age, we coded mother-infant interactions for maternal responses (accepted, redirected, ignored) to infant bids for attention. Maternal responses were further coded for multimodal behaviors (unimodal, bimodal, and trimodal) and speed of responding. The focus of infant gaze and maternal gaze were also coded (toy, partner, other). Results indicate that mothers engaged in more attentionally salient behaviors (e.g., more multimodal behaviors) when redirecting than accepting infant bids for attention, and that infants responded to those redirections with more joint attention and more looking to toys. The current study builds upon prior work and illustrates a potential process through which maternal redirection of infant bids for attention may facilitate attention control and language.
Functional magnetic resonance imaging (fMRI) in awake infants has the potential to reveal how the early developing brain gives rise to cognition and behavior. However, awake infant fMRI poses significant methodological challenges that have hampered wider adoption. The present work takes stock after the collection of a substantial amount of awake infant fMRI data across multiple studies from two labs, at Yale University and Massachusetts Institute of Technology (MIT). These data were leveraged to glean insights on participant recruitment, experimental design, and data acquisition that could be useful to consider for future studies. Across 766 fMRI sessions with awake infants aged 1-36 months, the authors explored the factors that influenced how much usable data were obtained per session. The age of an infant predicted whether they would successfully enter the scanner (younger more likely) and, if they did enter, the number of minutes of functional data collected (linear, younger more) and retained after preprocessing with lab-specific protocols or harmonized motion exclusion thresholds (quadratic, 12-24 months more than younger and older). The amount of functional data retained was also influenced by assigned sex (female more), experimental paradigm (movies better than blocks and events), and stimulus content (social better than abstract). There were many differences in the research approach between labs making head-to-head comparisons difficult, but Yale was more likely to get infants into the scanner, MIT collected more data from infants who entered, and the amount of data retained after preprocessing did not differ statistically between labs (9 min). In addition, the authors assessed the value of attempting to collect multiple experiments per session, an approach that yielded more than one usable experiment averaging across all sessions. Although any given scan is unpredictable, these findings support the feasibility of awake infant fMRI and suggest practices to optimize future research.
Social odor plays an important role for various facets of early development, including communication and social processing. Previous research focusing on maternal odor has shown that smelling the mother can influence face processing in general as well as emotion processing more specifically. However, it is unclear to what extent these effects are specific to maternal odor or can also be found for other familiar social odors. To address this question, we investigated the impact of the father's odor on emotional face processing in 7-month-old infants (age at appointment 1: 209 ± 6 days [mean ± SD], range: 199-225 days; age at appointment 2: 217 ± 6 days, range: 206-231 days; gender: 15 girls and 15 boys). We recorded the infant's EEG response to female and male happy and fearful faces while infants were exposed to either their father's odor or the odor of a different infant's father. Analysis of the frontocentral Nc amplitude revealed an enhanced response to fearful compared to happy male faces only when infants smelled their own father but not when they smelled an unfamiliar father. In contrast, emotion processing at the occipital N290 was not affected by the presence of paternal odor, suggesting an impact of social odor on attention allocation rather than structural face processing. Interestingly, all effects were specific to male faces, pointing to a gender-specific impact of social odor. Our findings therefore provide first evidence for an influence of the father's odor on face processing, specifically male faces, in infancy.
Values help shape behavior and influence how individuals assess themselves and others. Previous research on the relation between values and parenting has largely overlooked the impact of values on parenting during infancy. This study is the first to link parents' value systems to contexts meaningful to parents of infants-sleep and parent-child interactions. We explored the value systems underlying individual differences in parents' cognitions about their infants' sleep, including whether there were gender differences in parents' values. We examined whether those values directly related to their own parenting behaviors and interactions with their infants, and whether those values subsequently related to the quality of their infants' sleep. 1685 parents of infants (3-18 months) participated in an online survey on values and parenting-related choices and beliefs. Families used Nanit, a video baby monitoring system that uses computer vision technology to calculate nightly summary sleep characteristics (e.g., quality of night sleep, parent visits, night wakings). Value profiles depended on parent gender and were associated with cognitions about infant sleep and with parents' interactions with their infants, but were not associated with the quality of infants' sleep. These findings have implications for anticipating factors that could be stressful around the transition to parenthood and for interventions targeting parents' mental health and infants' sleep health.
In this study, the psychometric properties of the 6-month age interval of the Ages and Stages Questionnaires: Social-Emotional, Second Edition (ASQ:SE-2) in its English and traditional Chinese versions were examined by using item response theory. A total of 2612 and 915 caregivers from the United States and Taiwan, respectively, were asked to complete the ASQ:SE-2 to evaluate the social-emotional development of their infants, aged 3 months and 0 days to 8 months and 30 days. Psychometric analysis revealed promising item fit, with item difficulty consistent with the instrument's intended purpose. Nevertheless, low reliability was observed, with scores of 0.64 for the US sample and 0.66 for the Taiwanese sample. Differential item functioning (DIF) analysis identified significant differences in item function between the two cultural samples, with 40.9% (9 of 22) of the items having moderate to large DIF values. These items belonged to the self-regulation, adaptive functioning, social communication, and interaction domains of the ASQ:SE-2. These differences likely stemmed from differences in culture. Overall, these findings contribute to a deeper understanding of how this parent-reported instrument functions across cultural groups, and they underscore the importance of culturally sensitive adaptations in international contexts.
Positioning-the body's physical configuration and relations to supports and restraints-is a fundamental aspect of infants' everyday experiences. How do everyday positioning experiences (the amount of time spent in different positions during daily life) change with the acquisition of postural skills like sitting? This study investigated relations between sitting status (whether infants have achieved a sitting milestone), sitting age (amount of time before or after that milestone), and everyday positioning experience. Forty-three infants participated at 4, 5, 6, and/or 7 months of chronological age. Everyday experience was measured using Ecological Momentary Assessment: Caregivers reported infants' current position repeatedly throughout their daily activities. The best predictors of everyday sitting experience (proportion of responses in which the infant was in an unrestrained sitting position) were chronological age and overall sitting age, calculated from the first day infants sat using hands for support; hands-free sitting age, calculated from the first day infants sat without hands, did not uniquely contribute. Sitting experience supplanted supine experience, which decreased with overall sitting age; the effect of overall sitting age on prone experience varied with chronological age. Time restrained by an adult decreased only with chronological age, and time restrained by a device was not related to chronological or sitting age. Results suggest that the continuous development of sitting skill changes the positioning composition of infants' everyday unrestrained floor time.
Parents use digital media to manage children's emotions-known as media emotion regulation. While research has focused on toddlers/preschoolers, media emotion regulation may begin in early infancy, potentially influencing media habits and socio-emotional development. Guided by the DREAMER framework, this longitudinal study examined media emotion regulation among 163 mother-infant dyads when infants were 2, 3, 4, and 5 months old. We also examined maternal, family, and infant characteristics associated with media emotion regulation (e.g., maternal depression, smartphone use, infant stressful behavior) and potential changes in infant socio-emotional outcomes (e.g., infant clarity of cues, responsiveness to mother). Data sources included monthly surveys, ecological momentary assessment (EMA) surveys, passive sensing of maternal smartphone use, and feeding observations at 2 and 5 months. Results revealed the prevalence of media emotion regulation increased from 12% at 2 months to 23% at 5 months. At 2 months, media emotion regulation was associated with greater maternal emotional dysregulation and negative perceptions of infant behavior. By 4 or 5 months, smartphone use and sensitivity began to be associated with media emotion regulation. These and other results suggest media emotion regulation may stem from maternal emotional dysregulation and stress during the early months but may become habitual over time.
Grasping is a fundamental skill that enables people to interface with and explore objects around them. The emergence of precision (thumb-to-forefinger) grasping during infancy represents a developmental shift in this skill and has been linked to more advanced action perception, particularly in detecting action incongruencies. In this study, ERPs known to be elicited in response to action were studied in 9- and 11.5-month-old infants as they watched whole-hand and precision grasping actions congruent or incongruent with a target object. Components related to attentional (Nc, P400) and semantic (N400) processes were examined to determine whether infants' perception of grasp is based on attention and recognition, on higher-level representations of action, or a mix of these two levels of processing. Effects of congruence were found for the P400 and the N400. The P400 effect was greater among the older age group. Infants' ability to produce a precision grip did not significantly affect their ERPs in response to actors' incongruent versus congruent grasps, which would have been expected if recognition of incongruous grasping actions were based on motor experience. Results indicate that infant ERPs differ between grasps that are congruent or incongruent with the form of a target object via multiple cognitive processes.
While early life sets the stage for later learning, comparatively less is known about newborns' cognition than that of older infants. A striking example is the lack of consensus regarding the extent to which newborns spontaneously mimic gestures, and whether such behavior drives bonding and learning. Despite the theoretical importance of these questions, practical challenges limit researchers' ability to engage newborns in behavioral research. Webcam-based, asynchronous online studies have expanded developmental science's capacity to reach older infants. However, such scalable and replicable methods have yet to be deployed with younger infants. Taking a commonly-used neonatal mimicry paradigm as a test case, we assessed the feasibility of leveraging an open-source online platform (Children Helping Science) for asynchronous research with 0-6-week-olds and their caregivers. Caregivers modeled face movements to their 4-45 days-old infants (N = 29, N = 17 included) while webcams filmed their infants' responses; 13 dyads participated more than once (72 included test videos). Preliminary evidence suggested that infants do not mimic caregivers' tongue protrusions (Bayes Factor ∼ ⅓). Data on the mimicry of caregivers' mouth openings was inconclusive (⅓ < BF < 3). Additional analyses identified a target sample size for future studies. Finally, we asked whether caregivers perceived their newborns' behavior as imitative. Caregivers' perceptions of mimicry reflected infants' behaviors but did not align with an often-used metric of mimicry ("imitators"). These results demonstrate the feasibility of asynchronous online behavioral studies with newborns and provide a foundation for future research on neonatal mimicry of caregivers.
Interactions with caregivers play a crucial role in early development. While most of the world's children live in Majority World countries, research on caregiving predominantly uses measures developed in the Minority World (particularly North America and Europe), potentially biasing characterizations of parenting in understudied populations. This study describes the development of the "Demba Yaal Interaction Scale (DYIS)", a behavioral micro-coding scheme to assesses caregiver responsiveness in a rural, low-resource, collectivist caregiving community in The Gambia. We adopted a contextually sensitive approach by co-creating the scheme partnering Gambian researchers, familiar with the caregiving context, and UK researchers familiar with behavioral coding. The scheme was piloted on 5-min videorecorded mother-infant interactions, when infants were aged 12-months (N = 50, 48% female). There were substantial individual differences in maternal responsiveness levels. Modality-wise, responses were most likely to be non-verbal, compared to verbal or bimodal. Mothers with some formal education were significantly more responsive and more readily engaged in bimodal responsiveness. Negative associations between these interactive behaviors and maternal demographic and socioeconomic variables (age, number of children, household size) were present but did not remain significant after correction for multiple comparisons. Moreover, associations emerged between infant physical growth and infant behaviors, as well as between maternal responsiveness and infant communication, although these too, did not remain significant after correction for multiple comparison. Our work provides a potential framework for future research seeking to develop contextually tailored assessments of caregiving practices and highlights important demographic and health variables that warrant further examination in larger samples.
Positive social bidding refers to moments when infants look at an unresponsive caregiver and try to re-engage the social partner via smiling and/or vocalizing. Prior to six months of age, there is considerable variability in the extent to which infants engage in positive social bidding. In this study we explore whether infants' and mothers' cardiac vagal tone is associated with these individual differences. Mothers and their 4- to 6-month-old infants (n = 132) participated in the Face-to-Face Still-Face Paradigm (FFSF); social behaviors and respiratory sinus arrhythmia (RSA) were recorded on a moment-to-moment basis. More frequent vocal bidding during the Still-Face episode was related to infants' and mothers' physiological synchrony, as well as lower levels of infants' negative affect and higher levels of infants' RSA during face-to-face Social Play. Also, infants demonstrating more vocal bidding exhibited greater increases in RSA at the beginning and end of the Reunion phase following the Still-Face stressor. Critically, the relation between infants' physiological regulation and vocal bidding differed as a function of the FFSF episode in which RSA was measured. The implications of adopting a biobehavioral perspective on the development of positive social bidding are discussed.
Smartphones can absorb attention and abruptly interrupt social interactions, a dynamic particularly critical in early parent-infant exchanges where infants rely on emotionally available caregivers for regulation. While previous research highlights the negative effects of parental media use on parenting and infant behavior, little is known about how maternal smartphone use affects both mothers' and infants' physiological and behavioral stress responses during early interactions. Consequently, we observed 67 mothers and their 6-month-old infants during an extended still-face paradigm including five phases in total: (1) an interaction baseline, (2) a still-face interruption, (3) a subsequent reunion, (4) a smartphone interruption, and (5) a subsequent reunion. The order of interruptions was randomized. Maternal and infant heart rates were continuously recorded via electrocardiogram. Infant protest and self-regulatory behaviors, as well as maternal co-regulatory behaviors, were coded from video recordings on a frame-by-frame basis. Infants showed significantly more protest behavior, higher cardiac arousal, and reduced parasympathetic activity during maternal smartphone use compared to baseline. During smartphone use, mothers reduced social engagement, accompanied by increased parasympathetic activity and decreased physiological arousal, which remained lower during reunions. We also found that dyadic physiological coupling emerged during still-face and smartphone disruptions, whereas dyadic behavioral coupling was observed only during the baseline interaction. These findings highlight the disruptive effects of maternal smartphone use and raise important questions about the potential cumulative effects of repeated smartphone interruptions on early socioemotional development.
Infants are growing up in a complicated digital world, where media within the household is used to meet varying needs of the family. This paper is a version of the Presidential Address I gave in 2024 to the International Congress on Infant Studies in Glasgow. The address focused on convergence, defined as the replication of core findings across multiple methodological approaches, using examples drawn from family media ecology. The CAFE consortium is provided as an illustration of a global collaboration which created more precise measures of family media ecology and measured more diverse populations. The Dynamic Relational Ecological Approach to Media Effects Researcher (DREAMER) framework shaped the discussion from the role of individual child factors to broader structural factors. Converging findings on infant cognitive constraints on learning from media via the transfer deficit were discussed. Then both amelioration of the transfer deficit via joint engagement and exacerbation of negative outcomes due to technoference demonstrated the dynamic and relational nature of family media ecology. Structural factors, such as the COVID pandemic, drastically changed family media ecology globally. For some digital inequity led to underconnectivity and poorer outcomes and for others digital connection via videochat supported infant outcomes. Taken together the review concluded that multiple converging evidence-based findings are needed to tackle complex problems like growing up the digital age.
The literature on alternative approaches to complementary feeding, especially Baby-Led Weaning (a complementary feeding approach in which infants participate in family meals and eat finger food independently), has gradually increased in recent years. The present study aims to investigate whether there is a relation between the complementary feeding approach chosen by parents (Baby-Led Weaning or Parent-Led Weaning, in which infants are fed puréed food on a spoon) and maternal communicative functions produced during a typical meal. We analyzed the transcripts of mother-infant interactions occurring during mealtimes of 136 12-month-old typically developing infants, by means of a validated coding scheme that allows to identify five different communicative functions (Tutorial, Didactic, Conversational, Control and Asynchronous). The results highlighted a slightly different pattern of communicative style depending on the feeding method adopted by the parents (BLW vs. PLW). In particular, mothers of infants exposed to the PLW approach used the Tutorial function more often than mothers of infants exposed to the BLW method. The two groups did not differ in their use of the other functions. The implications for the promotion of healthy eating behaviors within family interactive contexts are discussed.
This study explores how physical contact is used in parent-infant dyads from 9 to 12 months of age, focusing on the role of touch and the use of objects in supporting language development. Thirty-five monolingual Spanish-speaking dyads were observed longitudinally in a free play situation. We analyzed physical contact, considering who initiated the contact, its function, the use of objects and the coordination with speech. Results showed that adults initiated physical contact more frequently than infants, particularly at 9 months, while infant-initiated touch tended to be longer in duration and predominantly affective in nature. In contrast, adult-initiated touch was often functional and, when involving objects, frequently accompanied by verbal input. Notably, these object-mediated tactile cues were used to convey social meanings and were synchronized with speech, suggesting a scaffolding function for lexical development. As infants' comprehension increased, the frequency of these cues decreased, indicating a developmental shift toward more distal communication strategies. These findings highlight the importance of tactile interaction in multimodal communication and in the establishment of joint attention frames, especially during the period of transition to first words, underscoring the need for a broader understanding of language as a multimodal phenomenon.