Biologically inspired models of visual salience-rooted in the architecture of the primate visual system-offer powerful evidence that bottom-up visual attention is one mechanism used to select information from noisy environments across development. In contrast, parallel models of auditory salience remain underdeveloped and, critically, have never been applied to understand attention in early life. Here, we modelled the auditory salience in maternal speech during naturalistic dyadic interactions with 2-5-month-old infants (N = 221 in South Africa and Malawi) using two neurobiologically-informed computational models of auditory salience (Duangudom & Anderson, 2007; Kalinli & Narayanan, 2007). Then, we asked how moment-to-moment changes in salience related to infant looking towards their mother as evidence of bottom-up auditory attention in early life. Our results show that infant looking towards their mother is strongly related to maternal auditory salience, as defined by both models, and in both countries. This work provides the first evidence of bottom-up auditory attention in infancy, and suggests infants respond to changes in the salience of maternal signals to guide attention during naturalistic, dyadic interactions.
In spite of extensive evidence from studies in the Western contexts that maternal sensitivity and infant temperament are associated with emotional and behavioural adjustment in early childhood, we do not know whether this is the case in non-western cultural contexts. We investigated whether early maternal sensitivity to infant's distress and irritable infant temperament predict child's externalizing and internalizing problems at age 1, and whether maternal sensitivity to distress moderated the association between irritable temperament and child mental health outcomes in a sample of mother-infant dyads in India. The sample comprised 195 dyads taking part in the Bangalore Child Health and Development Study (BCHADS) in India. Maternal sensitivity to distress was assessed during a video-recorded free-play interaction at age 6 months and coded using the National Institute of Child Health and Human Development (NICHD) coding scheme. Infant irritable temperament (distress to limitations) was assessed at 6 months using a validated 8-item subset of Infant Behavior Questionnaire - Revised (IBQ-R), and child internalizing and externalizing problems at 1 year using the Brief Infant Toddler Social Emotional Assessment (BITSEA) respectively. Data was analyzed using regression and moderation analysis. After accounting for socio-demographic confounders and maternal depressive symptoms at the time of outcome report, maternal sensitivity to distress and infant's irritable temperament at 6 months independently predicted externalizing behaviors at age 1. High infant irritability and low maternal sensitivity functioned as distinct, additive risks; no significant moderation effect was observed. Neither predictor was associated with internalizing problems. These findings provide the first evidence from India linking early sensitivity to distress with externalizing problems, and are not dissimilar to those reported in Western settings. The independent contributions of temperament and maternal sensitivity suggest a two-pronged intervention approach: enhancing maternal sensitivity while simultaneously providing specific support for parents of irritable infants.
The facial feedback hypothesis suggests that facial muscle activity contributes to emotion perception, but the developmental origins of this mechanism remain underspecified. This theoretical paper argues that caregiver mirroring - specifically caregivers' contingent imitation of infant facial expressions - plays a critical role in establishing the facial feedback mechanism. Drawing on previous empirical findings, we propose that repeated episodes of being mirrored provide infants with reliable sensorimotor contingencies linking facial action, proprioceptive feedback, and emotional states. We further consider situations that impede caregiver mirroring - such as infant dummy (pacifier) use and caregiver botulinum toxin (Botox) treatment - as naturalistic perturbations of these contingencies. This paper highlights how caregiver facial mirroring may scaffold infants' developing emotion processing, offering a socially embedded perspective on the early development of embodied emotional understanding.
Examining how toddlers’ emerging self-regulatory capabilities relate to later behavioral outcomes is important for understanding internalizing and externalizing problems during early childhood. Child self-regulation may serve as a promotive factor, with children demonstrating stronger self-regulation showing resilience against adverse environmental influences. In the current study, we examined the longitudinal relations between toddler temperament, self-regulation, and maternal internalizing symptoms assessed at 18 months, and toddler internalizing and externalizing problems at 24 months. Data were drawn from a longitudinal study on attention and temperament (name masked for review; 24-month follow-up sample: n = 52; 55.8% girls and 44.2% boys; complete-case analytic sample: n = 44). Toddler self-regulation was assessed using a modified Still-Face Paradigm designed to reflect technoference, capturing regulatory behaviors in the context of modern digital parenting. We found that specific temperamental dimensions differentially predicted internalizing and externalizing problems, while maternal internalizing symptoms and toddler behavioral regulation were associated with both internalizing and externalizing problems at 24 months of age. Importantly, toddler self-comforting behaviors during the modified still-face task remained a significant negative predictor of internalizing and externalizing problems at 24 months, even after accounting for maternal internalizing symptoms. Our findings support the role of toddler behavioral regulation as a potential protective factor against emotional and behavioral difficulties in early childhood above and beyond the contribution of maternal mental health.
Infant reaching and grasping scaffold opportunities for exploration, learning, and communication, making them central to early development. Yet most prehension research relies on laboratory methods, which constrain sample sizes and the density of longitudinal follow-up. Here we used automated pose estimation (HaMeR) to extract markerless hand-pose features from in-home videos recorded by caregivers biweekly from 6 to 13.5 months of age (N = 63 infants; 881 videos; M = 13.98 videos per infant), tracking hand configuration across normalized reach time to reveal the within-reach dynamics of preshaping. We examined two components of preshaping: the opening between the thumb and index finger (aperture) and the tucking of the supporting fingers (supporting digit flexion). Flexible nonlinear modeling revealed distinct developmental trajectories for each component. By 6 months, infants were already tucking the supporting fingers about halfway through the reach, and by 11 months this adjustment shifted earlier. Anticipatory aperture control, in contrast, did not emerge until around 9-10 months, after which the moment of peak opening also shifted progressively earlier in the reach. The two components thus followed distinct developmental timelines, indicating partially independent control processes and suggesting that supporting digit flexion consolidates earlier, providing a foundation for the later refinement of grasping. Pairing in-home assessment with machine-learning-based pose analysis reveals developmental dynamics that laboratory methods cannot capture at this density, opening new opportunities to study infant motor development at scale in naturalistic settings.
Infants' experience with the auditory world is culture-specific and shapes how their brains process complex sounds in their environment. The present study is the first to examine naturalistic exposure to speech and music, two main components of infants' auditory soundscapes, in Latinx U.S. infants (n = 64; age range 4-23mo). Through a bootstrapping approach, results are then compared to a previously published dataset of non-Latinx U.S. infants. Two daylong audio recordings per infant were captured with LENA. Using a crowdsourcing approach, 417 naïve listeners annotated a total of 6400 randomly sampled short audio snippets through an online citizen science platform. Latinx infants received more speech input than music input, replicating previously published results with non-Latinx infants. Likewise, as was the case for non-Latinx infants, Latinx infants were exposed to more music from an electronic source than an in-person source; a pattern that was again reversed for speech. However, while non-Latinx infants experienced more non-infant-directed (non-ID) music compared to infant-directed (ID) music, the opposite was true for Latinx infants: they experienced more ID music compared to non-ID music. Latinx infants also experienced overall more music, and more ID music, compared to their non-Latinx counterparts. Together, these results point to nuanced but important differences between the auditory environments of Latinx and non-Latinx infants. Enhanced exposure to ID music in the Latinx group may act as a promotive factor in a range of developmental areas and should be considered when evaluating infants' auditory environments.
Caregiver-infant interactions shape the home environment in intentional and unintentional ways, creating different opportunities for action. In this sense, research should prioritize real-world contexts. The study aimed to characterize the emergence and transition of locomotor behaviors within the developmental pathways of typically developing Brazilian infants across two age cohorts. Group 1 included nineteen infants followed from five to eleven months-old and Group 2, eighteen infants from nine to fifteen months-old. Families recorded approximately eight minutes of infant home free play every two weeks. Locomotor bouts were classified as belly crawling, hands-and-knees crawling, hands-and-feet crawling, asymmetrical crawling, knee-locomotion and walking. Emergence was defined as the first appearance of a behavior in the repertoire, and transition as a change in behavioral predominance between recordings. Interindividual variability was observed, with fifteen emergence and twelve transition pathways for Group 1 and eight emergence and thirteen transition pathways for Group 2. Most emergence and transition events involved hands-and-knees crawling and walking. Non-traditional behaviors also contributed to pathways. Asymmetrical crawling emerged for most infants from Group 1. Transition events occurred in multiple directions, from less to more complex behaviors and vice versa. Locomotor development was characterized by diversity and non-linearity in behavioral preference and sequencing.
Mind-mindedness refers to parents' or caregivers' ability to view their child as an independent person with individual thoughts and intentional behaviors. Representational mind-mindedness assessment focuses on the caregiver representations of their child's mental states, (e.g., emotions, preferences, and goals). Individual differences in mind-mindedness have been associated with parental caregiving and child outcomes. However, there is a lack of research examining dynamic clusters of mind-related parental representations and their associations with demographic and psychological risk factors. Here, we conducted three sets of latent profile analyses (LPAs) to examine mind-mindedness profiles (Aim 1) and whether mothers belonging to the different classes could be distinguished by their demographic and psychological risk characteristics (Aim 2) in a sample of 181 mothers with infants (M=32.95 years, SD=4.66). Results indicated unique profiles for all three LPA models: 1) when examining mental-attribution profiles between different probes about the present and future infant, three profiles emerged representing high, medium, and low mind-mindedness; 2) when examining relative mind-related attributions versus the non-mental categories, two classes emerged, differing in physical and self-referential attributes; and 3) when examining representational valence, three profiles representing different dominant valence (high in either positive, neutral, or negative attributions) emerged. Associations with demographic factors were identified for each class. This work supports the utilization of LPA for identifying clusters of mind-related representations and demographic differences across groups for the first time. Future work should continue to assess mind-mindedness profiles as they relate to parent factors to disentangle the components of mind-mindedness which are most influential.
Although parental emotional challenges and emotion-based media motivations are linked to screen media use patterns in families of toddlers, little work has examined parental emotion regulation strategies in relation to parents' and toddlers' screen media use. Because these strategies are modifiable components of how parents manage emotional demands, investigating them is an important next step for understanding factors associated with family media use and informing media guidance. The present study examined associations between maternal emotion regulation strategies (expressive suppression and cognitive reappraisal) and both maternal and toddlers' screen media use, distinguishing between non-interactive and interactive forms given their differing implications for toddler development. Mothers of toddlers (18-36 months, N = 296) reported their emotion regulation strategies and both their own and their toddlers' screen media use through an online survey. Data were analyzed using multivariable regression models, with additional analyses testing indirect associations. Results indicated that higher levels of maternal expressive suppression were associated with greater maternal non-interactive screen media use and with both types of toddlers' screen media use. Higher levels of maternal non-interactive screen media use were linked to greater non-interactive and interactive screen media use among toddlers, whereas maternal interactive screen media use was not related to either form of toddlers' screen media use. No significant associations were found between maternal cognitive reappraisal and maternal or toddlers' screen media use. These findings highlight the differential roles of parental emotion regulation strategies in maternal and toddlers' screen media use, particularly the distinct role of expressive suppression relative to cognitive reappraisal, and offer implications for supporting healthy family media practices.
We examined whether specific maternal-perceived prenatal life stress predicted infant cortisol output at 2 or 6 months. Expectant mothers reported the occurrence and perceived impact of 47 potential prenatal life stressors. Infant cortisol was assessed across four salivary samples collected during a laboratory/home visit including stressful activities. Associations were examined between infant cortisol output and each potential life stressor, accumulation of stress within 7 distinct categories, and total stress accumulation. Although total stress was associated with higher infant cortisol output, only four specific perceived life stressors (i.e., serious accident/illness, mental health challenges, and trauma experience (self and partners')) within two categories (health/mental health and vicarious stress) predicted heightened infant cortisol output after adjusting for covariates and the false discovery rate. Findings suggest that more severe stressors related to health/mental health may be more salient for early development of the hypothalamic-pituitary-adrenal system than less severe stressors (e.g., moving). Aggregating stressors regardless of severity may obscure meaningful effects.
Executive functioning (EF) in early childhood plays a critical role in shaping later cognitive, socioemotional, and academic outcomes. Although the influence of caregiving on EF is well documented in preschool and older children, relatively little is known about how early relational factors contribute to the emergence of rudimentary EF abilities during the first year of life. The present study examined the contributions of maternal sensitivity and mind-mindedness to the emergence of EF in infancy. Fifty-one typically developing infants aged 9-13 months were invited to participate. Infants completed the A-not-B task to assess their EF abilities. Maternal sensitivity and appropriate mind-minded comments were assessed during a structured interaction task, which included both non-distress (free-play) and distress-eliciting episodes. Results showed that both maternal sensitivity and appropriate mind-minded comments were related to infant EF, yet only mind-mindedness in non-distress contexts emerged as a significant predictor of early EF abilities. These findings emphasize the importance of caregivers' attunement to their infants' mental states in fostering the emergence of EF.
Infants learn through everyday interactions with the physical and social environment. For infants with cerebral palsy (CP), motor impairments may disrupt everyday learning opportunities. How can we measure real-world motor behavior and learning opportunities in infants with CP? Machine learning models have been developed to quantify body position throughout a day in infants with typical development (TD) using wearable sensor data. However, these models have not been validated in infants with motor impairments. This study assessed the validity of body position classification using machine learning and sensors in infants with CP. Ten infants with CP (7-18 months; one session each) and 19 infants with TD (4-12 months; 45 sessions) wore four inertial sensors on their legs throughout a day. Ninety minutes were video recorded and manually scored for body position in five categories: supine, prone, sitting, standing, and held. Random forest classifiers were trained to predict body position from sensor-derived motion features. Models trained on datasets that varied in size (9, 45, 54 sessions) and group composition (CP, TD, CP and TD) were compared to determine the most accurate model for infants with CP. Larger training sets and training sets that included data from infants with CP were the most accurate; the final models achieved similar performance in CP and TD (86% and 89% accuracy), captured meaningful individual differences (ICCs = 0.682-0.999), and generated predictions that were correlated with motor skill assessments. Findings demonstrate that wearable sensors and machine learning can accurately classify real-world body position in infants with CP.
Early environmental unpredictability has been linked to variation in cognitive and socioemotional development, yet its role in shaping foundational attentional processes during infancy remains poorly understood. The present study examined whether unpredictability in household resources is associated with individual differences in visual attention during the first year of life. A sociodemographically diverse sample of 160 infants aged 3-12 months completed a remotely administered free-viewing visual attention task. Infant eye-gaze behavior was assessed using webcam-based eye-tracking, yielding measures of total looking time, peak look duration, and gaze shifts. Results indicated that infants of caregivers who reported higher resource unpredictability exhibited more gaze shifts during the attention task, even after accounting for the severity of resource deprivation. An exploratory analysis examining gaze shifts during the encoding phase of a visual paired-comparison task showed a similar pattern, providing convergent evidence across attention measures. Together, these findings suggest that early exposure to unpredictable resource environments may be associated with an attentional profile characterized by more frequent shifts in gaze rather than reduced attentional capacity. By distinguishing unpredictability of resources from the severity of material deprivation, this study contributes to a growing body of research examining how early environmental instability may shape emerging attention processes.
The transactional model of sleep identifies interactions between multiple factors, including infant temperament, parenting, and context contribute to variability in infant sleep. Research has focused on between-person designs and subjective or short observation periods, limiting the ability to examine variability in infant sleep. The present study utilized between-person methodologies to examine how supportive parenting and three temperamental characteristics were related to variability (i.e., fluctuations in sleep over time) and inertia (i.e., day-to-day influence of sleep) to capture stability in within-person sleep outcomes. Participants included parents (N = 208) of 4- to 12-month-old infants who were recruited by emails to Nanit baby monitor users. Sleep metrics from the Nanit baby monitor were provided nightly for up to two weeks, including total sleep time (TST) and parent visits to crib (PVC) through autovideosomnography and computer vision techniques from the Nanit. Participants completed questionnaires assessing infant temperament and parenting quality. Using dynamic structural equation modeling, we found that infant negative emotionality was associated with more TST inertia and lower PVC inertia. Infant effortful control was associated with more PVC inertia and lower TST inertia. Supportive parenting was associated with lower TST inertia and higher PVC inertia. When caregivers were higher in supportive parenting, there was a positive association between infant negative emotionality and TST inertia. In support of the transaction model of infant sleep, the current findings integrate social factors into infant sleep and build on infant sleep literature by identifying within-person variability in sleep behaviors in relation to infant temperament traits and supportive parenting.
Emotion regulation (ER) is a key developmental process shaped through parent-infant interactions, during which parents and infants dynamically co-regulate the infant's emotions. Successful co-regulation depends on parents' sensitivity to the infant's emotional cues; unadjusted parental responses, such as intrusiveness or withdrawal, can dysregulate the infant, reflected in physiological indicators such as heart rate (HR). Although research has advanced understanding of infant ER, most studies have focused on mothers and dyadic contexts and primarily compared infant HR during stressful versus non-stressful interactions, without examining the moment-to-moment dynamics of naturalistic interactions. We examined associations between infant HR and parental behaviors in three interaction contexts-mother-infant, father-infant, and triadic (mother-father-infant). Eighty families with three-month-old infants completed three successive two-minute free-play sessions corresponding to these contexts. Each session was divided into 5-s intervals, with parental intrusive and withdrawn behaviors (IWPBs) coded for intensity (0-4) and infant HR averaged per interval. Multilevel vector autoregression models were applied to assess lag-1 and contemporaneous effects at within- and between-family levels. IWPBs were associated with elevated infant HR, with cross-lagged effects showing that increases in IWPBs predicted subsequent increases in infant HR. For intrusive behaviors, associations with infant HR were bidirectional, suggesting dynamic co-regulation processes. Context differences also emerged: fathers showed delayed responses to infant arousal, whereas triadic interactions elicited stronger associations and higher HR levels when considering the whole sample. Overall, findings highlighted that parent-infant co-regulation is moment-to-moment, context-sensitive, and shaped by both parental behavior and infant physiological reactivity.
Autism Spectrum Disorder (ASD) is characterized by early challenges in social communication and behavioral flexibility, making timely behavioral analysis critical for early detection. We present a comprehensive framework for analyzing ASD-related child behaviors using a novel Play Behavior Protocol tailored to the Indian sociocultural context. Video recordings of semi-structured play interactions between the child, caregiver, and a clinically trained examiner were collected from children aged 0-36 months, including 34 children with ASD, 10 with developmental delay (DD), and 23 typically developing (TD) children. A comprehensive set of twenty-six behaviors, including facial, social, and play-based behaviors, were analyzed for frequency, duration, and variability across age and sex. Statistical analyses indicated that children with ASD exhibited reduced eye contact, social smiling, and joint attention, along with increased no affect, repetitive play, and solitary play compared to TD children. Additionally, children with ASD demonstrated lower levels of eye contact compared to children with DD. Furthermore, participant-level ratios, such as the eye-contact-to-gaze ratio and the social-smile-to-positive-affect ratio, emerged as potentially important markers for distinguishing ASD from DD and TD, with both ratios being lower in the ASD group compared to the DD and TD groups. Automated multimodal analysis of facial affect and gaze cues revealed that children with ASD exhibited reduced human-directed gaze, lower levels of happy and surprise expressions, and increased sad expressions compared to children with DD and TD. By integrating culturally contextualized data collection, systematic statistical analysis, and automated multimodal inference, this work presents the first comprehensive behavioral analysis framework of its kind for early ASD assessment in Indian children.
Spontaneous limb movements provide the foundation for motor development, yet knowledge of their normative characteristics has been limited by small homogenous samples and short observation windows. Leveraging the HEALthy Brain and Child Development (HBCD) study, we present descriptive characteristics of the first large-scale dataset of leg movements from 421 infants aged 0-2 months, captured with wearable sensors worn continuously for 72 h in naturalistic settings across multiple research sites in the United States. Our analysis focused on three domains: movement characteristics, variability of movement acceleration time-series, and physical activity intensity. Movement characteristics included leg movements per hour awake, peak acceleration per movement, average acceleration per movement, and movement duration. These characteristics aligned with earlier smaller-scale studies and showed highly consistent patterns between right and left legs. Sample entropy analysis revealed left-skewed distributions with median values near 1.3. Physical activity intensity estimations showed that infants spent the majority of time in sedentary activity, followed by light activity, with only brief periods of moderate-to-vigorous activity. Together, these findings provide initial characterization of multiple dimensions of infant leg movements, hence significantly contributing to derive reference distributions in early life. By establishing scalable, ecologically valid, and computationally tractable measures of infant motor behavior, this study lays the groundwork for integrating wearable sensing with longitudinal developmental science and for identifying early indicators of atypical trajectories. Ultimately, these findings contribute to the broader goals of the HBCD study: to understand how the brain develops and is shaped by environmental, social, and biological factors during pregnancy and after birth.
Segmental trunk control is central to upright motor development in preterm infants, yet evidence linking specific home environment attributes to condition-specific control in late infancy remains limited. This study aims to examine the associations between characteristics of commercial baby containers-defined as restricting equipment or furniture such as playpens and cots-and segmental trunk control during the standing-walking window. Additionally, age-related usage patterns of these containers from 8 to 13 months corrected age were described. In a prospective longitudinal study of 76 moderate-to-late preterm infants, caregivers provided monthly reports on container usage, specifically categorizing attributes of size, rail height, and floor surface compliance. Segmental trunk control was assessed monthly using the Segmental Assessment of Trunk Control (SATCo) under static, active, and reactive conditions. Results indicated that trunk control improved with age across all conditions, although reactive control initially developed more slowly than static and active control before converging at full proficiency by 13 months. Larger container size was consistently linked to better trunk control across static, active, and reactive conditions. Floor surface compliance also played a significant role; soft floors were associated with better static and active control but did not influence reactive control. Conversely, the height of the container rails showed no independent relationship with trunk control performance. Usage patterns shifted over time toward larger spaces and firmer surfaces. These findings suggest that in late infancy, expanded physical space consistently supports segmental trunk control, while surface compliance specifically benefits steady-state and anticipatory control. The results support low-cost, home-based guidance that encourages expanding safe play areas and selecting appropriately compliant surfaces to foster motor development in preterm infants.
Infants are provided unique, developmentally impactful experiences when in different positions. This research examined infant positioning over time, between assessment contexts, and in relation to child development. Infants one to six months old were assessed for six months. Infant position was measured during ten-minute play sessions using computer vision and across two full days when awake using a smart garment. Percent time supine, reclined, upright (sitting or standing), inclined, and prone were quantified. Linear mixed-effects models and Spearman correlation analyses were used to evaluate the data. Forty-nine dyads enrolled. Over time, infants spent less time supine and more time upright. Less time in supine was correlated with more advanced motor development. Infant positioning varied when assessed in different contexts. These findings highlight how infant positioning behavior changes across time, can be measured using novel technologies, and may be influenced by the context of measurement.
Capturing the complexity of infant behavior in naturalistic contexts remains a primary challenge in developmental science. High-density sensing can address this, but its adoption has been limited by the need for specialized, expensive, and physically intrusive hardware. We developed Expressions, an iOS application and data processing pipeline that repurposes Apple's TrueDepth camera system as a contactless, multimodal data collection tool. The application passively collects 60 Hz data on over 50 low-level features of facial expressions, 3D head movements for up to three interacting individuals, and eye gaze direction, while concurrently recording synchronized audio and video of the environment. We deployed Expressions in two developmental studies to test the feasibility and flexibility of this approach. In the first study, toddlers watched emotional videos on a computer that wirelessly streamed event markers to the recording device. This timestamping allowed us to time-lock and analyze the toddlers' micro-expressive and emotional responses to positive versus negative stimuli. In the second study, two wirelessly networked iPads captured simultaneous data from caregiver-infant dyads during free-flowing play. This markerless, dual-device setup allowed assessment of complex interaction dynamics without disrupting the interaction itself. These studies show that consumer mobile devices are a feasible and flexible platform for studying infant behavior. Because the facial tracking in Expressions runs entirely on-device, the app does not require internet access during data collection. This privacy feature allows deployment not only in labs and urban homes but also in remote and rural communities that have been underrepresented in developmental research.
