Caregiver-infant Interaction Research Articles

Touch: A Review of the Infant-Caregiver Relationship in the Neonatal Field

Touch is a domain of enormous importance with implications in development, from birth, and across the lifespan. This work aims to review touch implications within infant-caregiver interaction. A non-systematic review of the literature was performed to assess the relevance of touch in the neonatal period, on attachment, and in child development. The review was conducted on PubMed database, in May 2023 using the following keywords: “infant”, “child”, “baby”, “newborn”, “neonatal”, “touch”, “contact”, “tactile”, and “attachment”. In the neonatal period, close skin contact facilitates caregiver sensitivity and responsiveness, promotes parent-infant reciprocity, reduces psychological distress both in caregiver and infants, and regulates the infant’s physiological systems (circadian rhythm, autonomic regulation). Touch also plays a crucial role in attachment by contributing to synchrony and self-regulation abilities, since secure attachment promotes learning of emotional regulation, social skills, and behavioural organization. Early sensory experiences are critical to developmental dimensions such as cognitive, motor, and socio-emotional, and influence physical growth rate. Concluding, in neonatal care services, touch should be systematically addressed in routine appointments. Within the field of infant-caregiver interactions, there is an urgent need to create a reliable tool for tactile assessment, allowing clear interpretations and the development of target interventions.

Exploring predictors of interaction among low-birth-weight infants and their caregivers: a machine learning–based random forest approach

BackgroundQuality caregiver-infant interaction is crucial for infant growth, health, and development. Traditional methods for evaluating the quality of caregiver-infant interaction have predominantly relied on rating scales or observational techniques. However, rating scales are prone to inaccuracies, while observational techniques are resource-intensive. The utilization of easily collected medical records in conjunction with machine learning techniques offers a promising and viable strategy for accurate and efficient assessment of caregiver-infant interaction quality.MethodsThis study was conducted at a follow-up outpatient clinic at two tertiary maternal and infant health centers located in Shanghai, China. 68 caregivers and their 3-15-month-old infants were videotaped for 3–5 min during playing interactions in non-threatening environment. Two trained experts utilized the Infant CARE-Index (ICI) procedure to assess whether the caregivers were sensitive or not in a dyadic context. This served as the gold standard. Predictors were collected through Health Information Systems (HIS) and questionnaires, which included accessible features such as demographic information, parental coping ability, infant neuropsychological development, maternal depression, parent-infant interaction, and infant temperament. Four classification models with fivefold cross-validation and grid search hyperparameter tuning techniques were employed to yield prediction metrics. Interpretable analyses were conducted to explain the results.ResultsThe score of sensitive caregiver-infant interaction was 6.34 ± 2.62. The Random Forest model gave the best accuracy (83.85%±6.93%). Convergent findings identified infant age, care skills of infants, mother age, infant temperament-regulatory capacity, birth weight, positive coping, health-care-knowledge-of-infants, type of caregiver, MABIS-bonding issues, ASQ-Fine Motor as the strongest predictors of interaction sensitivity between infants and their caregiver.ConclusionsThe proposed method presents a promising and efficient approach that synergistically combines rating scales and artificial technology to detect important features of caregiver-infant interactions. This novel approach holds several implications for the development of automatic computational assessment tools in the field of nursing studies.

Contingency and Synchrony: Interactional Pathways Toward Attentional Control and Intentional Communication

In this article we examine how contingency and synchrony during infant–caregiver interactions help children learn to pay attention to objects and how this, in turn, affects their ability to direct caregivers’ attention and to track communicative intentions in others. First, we present evidence that, early in life, child–caregiver interactions are asymmetric. Caregivers dynamically and contingently adapt to their child more than the other way around, providing higher-order semantic and contextual cues during attention episodes, which facilitate the development of specialized and integrated attentional brain networks in the infant brain. Then, we describe how social contingency also facilitates the child's development of predictive models and, through that, goal-directed behavior. Finally, we discuss how contingency and synchrony of brain and behavior can drive children's ability to direct their caregivers’ attention voluntarily and how this, in turn, paves the way for intentional communication.

The nutritional and feeding status of children living in selected residential child care facilities in Zambia: implications for programs and policies.

This study aimed to estimate the prevalence of undernutrition and risk of feeding difficulties and describe common feeding practices for children from birth to 10 years of age living in residential care in Zambia. This was a secondary analysis of de-identified cross-sectional data on 397 children living in 22 residential care facilities in four provinces. Child demographics, anthropometrics, hemoglobin levels, risk for feeding difficulties, and facility-level feeding practices were collected by a trained study team using Count Me In, a digital health app. Interviews with staff were conducted at 15 residential care facilities. Around half of the study sample were boys (53.4%) and <5 years old (55.4%). Special healthcare needs were reported in 10.3% of the children, with cerebral palsy being the most common (3.5%). Underweight, stunting, wasting (using weight-for-length/height), and anemia were found in 22.4, 28.0, 7.1 and 54.7% of children, respectively, with higher rates in children with special healthcare needs and children <24 months old. Duration of residential care was positively associated with length/height-for-age but not weight-for-age or weight-for-length/height z-scores. A risk for feeding difficulties was found in 41.4 and 26.0% of children with and without special healthcare needs, respectively. Suboptimal bottle-feeding practices, including the use of altered nipples and poor caregiver-infant interactions, were observed for infants <12 months old. Residential care staff reported suboptimal diets in their facilities and gaps in knowledge and resources to meet children's nutritional needs. These results demonstrate that a large proportion of children living in residential care in Zambia are at high risk for undernutrition and feeding difficulties and contribute to the small body of literature on children living in residential care, both in Zambia and globally. In the context of Zambia's efforts to improve child nutrition and reform its alternative care, these findings can inform programming and policies for children living in residential care to fulfill their rights to health and family care.

Infant-directed communication: Examining the many dimensions of everyday caregiver-infant interactions.

Everyday caregiver-infant interactions are dynamic and multidimensional. However, existing research underestimates the dimensionality of infants' experiences, often focusing on one or two communicative signals (e.g., speech alone, or speech and gesture together). Here, we introduce "infant-directed communication" (IDC): the suite of communicative signals from caregivers to infants including speech, action, gesture, emotion, and touch. We recorded 10min of at-home play between 44 caregivers and their 18- to 24-month-old infants from predominantly white, middle-class, English-speaking families in the United States. Interactions were coded for five dimensions of IDC as well as infants' gestures and vocalizations. Most caregivers used all five dimensions of IDC throughout the interaction, and these dimensions frequently overlapped. For example, over 60% of the speech that infants heard was accompanied by one or more non-verbal communicative cues. However, we saw marked variation across caregivers in their use of IDC, likely reflecting tailored communication to the behaviors and abilities of their infant. Moreover, caregivers systematically increased the dimensionality of IDC, using more overlapping cues in response to infant gestures and vocalizations, and more IDC with infants who had smaller vocabularies. Understanding how and when caregivers use all five signals-together and separately-in interactions with infants has the potential to redefine how developmental scientists conceive of infants' communicative environments, and enhance our understanding of the relations between caregiver input and early learning. RESEARCH HIGHLIGHTS: Infants' everyday interactions with caregivers are dynamic and multimodal, but existing research has underestimated the multidimensionality (i.e., the diversity of simultaneously occurring communicative cues) inherent in infant-directed communication. Over 60% of the speech that infants encounter during at-home, free play interactions overlap with one or more of a variety of non-speech communicative cues. The multidimensionality of caregivers' communicative cues increases in response to infants' gestures and vocalizations, providing new information about how infants' own behaviors shape their input. These findings emphasize the importance of understanding how caregivers use a diverse set of communicative behaviors-both separately and together-during everyday interactions with infants.

Developmental cascades of vocal turn-taking connect prelinguistic vocalizing with early language

Conversational turn-taking is ubiquitously found in caregiver-infant interactions, and robustly predictive of infant communicative development. Over the first year, infants take quick adult-like vocal turns with caregivers. Many studies have documented the consistency of caregiver responsiveness and its influence on infant rapid language growth. However, few have examined how caregiver responsiveness facilitates extended vocal turn-taking in real-time with infants over the first year. The influence of prelinguistic vocal turn-taking on the emergence of language has also been under-investigated. We analyzed free-play sessions of 30 caregivers and their infants at both 5 and 10 months, and obtained infant language outcomes at 18 months. We examined the developmental consistency (group-level continuity and dyad-order stability) and change of infant volubility, caregiver responses to babbling in vocal, non-vocal and multimodal modalities, and the influence of modality on caregiver-infant vocal turn-taking. Caregiver contingent responsiveness to infant babbling at 5 months predicted vocal turn-taking at 10 months. Developmental increases in prelinguistic vocalizing and vocal turn-taking from 5 to 10 months predicted infant language outcomes at 18 months. At both 5 and 10 months, caregiver vocal responses were more effective in extending turn-taking than non-vocal or multimodal responses. In summary, prelinguistic vocal turn-taking, facilitated by caregiver vocal responsiveness, is positively related to the emergence of early language.

Effects of cleft lip on visual scanning and neural processing of infant faces.

Infant faces readily capture adult attention and elicit enhanced neural processing, likely due to their importance evolutionarily in facilitating bonds with caregivers. Facial malformations have been shown to impact early infant-caregiver interactions negatively. However, it remains unclear how such facial malformations may impact early visual processing. The current study used a combination of eye tracking and electroencephalography (EEG) to investigate adults' early visual processing of infant faces with cleft lip/palate as compared to normal infant faces, as well as the impact cleft palate has on perceived cuteness. The results demonstrated a significant decrease in early visual attention to the eye region for infants with cleft palate, while increased visual attention is registered on the mouth region. Increased neural processing of the cleft palate was evident at the N170 and LPP, suggesting differences in configural processing and affective responses to the faces. Infants with cleft palate were also rated significantly less cute than their healthy counterparts (mean difference = .73, p < .001). These results suggest that infants' faces with cleft lip/palate are processed differently at early visual perception. These processing differences may contribute to several important aspects of development (e.g., joint attention) and may play a vital role in the previously observed difficulties in mother-infant interactions.

It’s You and Me: Infants’ cross-modal communicative signals and mother-infant interactive behavior predict infant regulatory patterns in the still-face paradigm at 3 months

Infant regulatory behavior develops since birth and impacts their early social interactions. Infants differ in the relative coherence and incoherence of their cross-modal communicative signals during en-face infant-caregiver interactions. We expand this research by evaluating whether different infant regulatory patterns observed during the Face-to-Face Still-Face (FFSF) at 3 months are associated with the coherence or incoherence of infants’ cross-modal communicative behaviors during en-face interactions or with multiple dimensions of mother-infant interactive behavior during free-play. Analyses were based on data collected from 100 mother-infant dyads from urban, working- and middle-class backgrounds in Portugal who were videotaped during the FFSF and free play at 3 months. Results confirm that infants’ different regulatory behavior patterns in the FFSF at 3 months are associated with the coherence and incoherence of their cross-modal interactive behaviors and specific aspects of mother-infant interaction. Infants with a Social-Positive oriented regulatory pattern during the FFSF displayed more coherent and less incoherent communicative behaviors with their mothers and were more cooperative during free play. In turn, their mothers were more sensitive. Our findings support the perspective that infants' regulatory behavior strategies in the context of caregiver regulatory support and sensitivity are likely to increase dyadic correspondence and infant ability to engage with the world.

Automatic assessment of infant carrying and holding using at-home wearable recordings

Assessing infant carrying and holding (C/H), or physical infant-caregiver interaction, is important for a wide range of contexts in development research. An automated detection and quantification of infant C/H is particularly needed in long term at-home studies where development of infants’ neurobehavior is measured using wearable devices. Here, we first developed a phenomenological categorization for physical infant-caregiver interactions to support five different definitions of C/H behaviors. Then, we trained and assessed deep learning-based classifiers for their automatic detection from multi-sensor wearable recordings that were originally used for mobile assessment of infants’ motor development. Our results show that an automated C/H detection is feasible at few-second temporal accuracy. With the best C/H definition, the automated detector shows 96% accuracy and 0.56 kappa, which is slightly less than the video-based inter-rater agreement between trained human experts (98% accuracy, 0.77 kappa). The classifier performance varies with C/H definition reflecting the extent to which infants’ movements are present in each C/H variant. A systematic benchmarking experiment shows that the widely used actigraphy-based method ignores the normally occurring C/H behaviors. Finally, we show proof-of-concept for the utility of the novel classifier in studying C/H behavior across infant development. Particularly, we show that matching the C/H detections to individuals’ gross motor ability discloses novel insights to infant-parent interaction.

A Review of Crying and Caregiving: Crying as a Stimulus.

The interactions between infants and caregivers are critical to infant development and caregiver well-being. Traditional developmental research has primarily emphasized the infant's development when studying infant-caregiver interactions, but a less commonly assessed feature of those interactions is the effect of the infant's crying on the caregiver's behavior. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method (Moher et al.,Public Library of Science Medicine, 6(7), e1000097, 2009), we conducted a systematic review of the literature evaluating the effects of crying on caregiver behavior. We searched for peer-reviewed articles in the Scopus and Web of Science Core Collection databases that included research studies in which researchers observed and manipulated infant crying and simultaneously measured features of caregiver behavior (actual or analogue). We used this body of literature to evaluate the existing evidence of the effects of crying on caregiver behavior, address the limitations and current gaps in our understanding of those interactions, and identify areas for future behavioral research.

The distributional and embodied contexts of verbs in caregiver-infant interactions.

The process by which infants learn verbs through daily social interactions is not well-understood. This study investigated caregivers' use of verbs, which have highly abstract meanings, during unscripted toy-play. We examined how verbs co-occurred with distributional and embodied factors including pronouns, caregivers' manual actions, and infants' locomotion, gaze, and object-touching. Object-action verbs were used significantly more often during caregiver-infant joint attention interactions. Movement and cognition verbs showed distinct co-occurrences with different contexts. Cognition and volition verbs were differentiated by pronouns. These findings provide evidence for how verb acquisition may be supported by the distributional and embodied contexts in caregiver-infant interactions.

Leveraging technological advances to assess dyadic visual cognition during infancy in high- and low-resource settings.

Caregiver-infant interactions shape infants' early visual experience; however, there is limited work from low-and middle-income countries (LMIC) in characterizing the visual cognitive dynamics of these interactions. Here, we present an innovative dyadic visual cognition pipeline using machine learning methods which captures, processes, and analyses the visual dynamics of caregiver-infant interactions across cultures. We undertake two studies to examine its application in both low (rural India) and high (urban UK) resource settings. Study 1 develops and validates the pipeline to process caregiver-infant interaction data captured using head-mounted cameras and eye-trackers. We use face detection and object recognition networks and validate these tools using 12 caregiver-infant dyads (4 dyads from a 6-month-old UK cohort, 4 dyads from a 6-month-old India cohort, and 4 dyads from a 9-month-old India cohort). Results show robust and accurate face and toy detection, as well as a high percent agreement between processed and manually coded dyadic interactions. Study 2 applied the pipeline to a larger data set (25 6-month-olds from the UK, 31 6-month-olds from India, and 37 9-month-olds from India) with the aim of comparing the visual dynamics of caregiver-infant interaction across the two cultural settings. Results show remarkable correspondence between key measures of visual exploration across cultures, including longer mean look durations during infant-led joint attention episodes. In addition, we found several differences across cultures. Most notably, infants in the UK had a higher proportion of infant-led joint attention episodes consistent with a child-centered view of parenting common in western middle-class families. In summary, the pipeline we report provides an objective assessment tool to quantify the visual dynamics of caregiver-infant interaction across high- and low-resource settings.

Motor Simulation and Ostensive-inferential communication: insights and clarifications

In the article , a theoretical model of how motor simulation is a mechanism that underlies language acquisition is described. It is argued that motor areas might play a role in both the recognition of linguistic communicative and informative intentions in infants, by activating brain regions dedicated to speech processing. In this paper, I will extend the position taken there (i) by connecting my model to the features of infant-caregiver interaction in speech perception, (ii) by explaining the process that causes brains to create networks between speech areas and the motor cortex, and (iii) by showing how the most influential mindreading models can be made compatible with both the embodied simulation theory and with the cognitive abilities in children.

Ten-month-old infants’ neural tracking of naturalistic speech is not facilitated by the speaker’s eye gaze

Eye gaze is a powerful ostensive cue in infant-caregiver interactions, with demonstrable effects on language acquisition. While the link between gaze following and later vocabulary is well-established, the effects of eye gaze on other aspects of language, such as speech processing, are less clear. In this EEG study, we examined the effects of the speaker’s eye gaze on ten-month-old infants’ neural tracking of naturalistic audiovisual speech, a marker for successful speech processing. Infants watched videos of a speaker telling stories, addressing the infant with direct or averted eye gaze. We assessed infants’ speech-brain coherence at stress (1–1.75 Hz) and syllable (2.5–3.5 Hz) rates, tested for differences in attention by comparing looking times and EEG theta power in the two conditions, and investigated whether neural tracking predicts later vocabulary. Our results showed that infants’ brains tracked the speech rhythm both at the stress and syllable rates, and that infants’ neural tracking at the syllable rate predicted later vocabulary. However, speech-brain coherence did not significantly differ between direct and averted gaze conditions and infants did not show greater attention to direct gaze. Overall, our results suggest significant neural tracking at ten months, related to vocabulary development, but not modulated by speaker’s gaze.

Within arms reach: Physical proximity shapes mother-infant language exchanges in real-time

During everyday interactions, mothers and infants achieve behavioral synchrony at multiple levels. The ebb-and-flow of mother-infant physical proximity may be a central type of synchrony that establishes a common ground for infant-mother interaction. However, the role of proximity in language exchanges is relatively unstudied, perhaps because structured tasks—the common setup for observing infant-caregiver interactions—establish proximity by design. We videorecorded 100 mothers (U.S. Hispanic N = 50, U.S. Non-Hispanic N = 50) and their 13- to 23-month-old infants during natural activity at home (1-to-2 h per dyad), transcribed mother and infant speech, and coded proximity continuously (i.e., infants and mother within arms reach). In both samples, dyads entered proximity in a bursty temporal pattern, with bouts of proximity interspersed with bouts of physical distance. As hypothesized, Non-Hispanic and Hispanic mothers produced more words and a greater variety of words when within arms reach than out of arms reach. Similarly, infants produced more utterances that contained words when close to mother than when not. However, infants babbled equally often regardless of proximity, generating abundant opportunities to play with sounds. Physical proximity expands opportunities for language exchanges and infants’ communicative word use, although babies accumulate massive practice babbling even when caregivers are not proximal.

Cross-modal coherence and incoherence of early infant interactive behavior: links to attachment in infants born very preterm or full-term

ABSTRACT Infants exhibit flexibly organized configurations of facial, vocal, affective, and motor behavior during caregiver-infant interactions that convey convergent messages about their internal states and desires. Prior work documents that greater cross-modal discrepancy at 4 months predicts disorganized attachment. Here, we evaluated whether: very preterm (VPT) or full-term (FT) status predicts cross-modal coherence or incoherence in infants’ behavior with the caregiver at 3 months; and, regardless of prematurity, whether cross-modal interactive coherence or incoherence predicts 12-month attachment. Participants included 155 infants (85 FT; 70 VPT), and their mothers followed from birth to 12 months (corrected age). Infants’ cross-modal coherent and incoherent responses were scored microanalytically from videotaped en-face interactions. Infants’ attachment security was evaluated during Ainsworth’s Strange Situation. Infants born VPT exhibited more incoherent cross-modal responses and insecure attachment than infants born FT. Regardless of prematurity, infants’ coherent and incoherent cross-modal interactive behaviors at 3 months predicted different attachment patterns at 12 months.

Using the Ages & Stages Questionnaire to assess later effects of an infant intervention promoting language in primary care

BackgroundPositive relational experiences during infancy have a profound impact on child development and are critical for future health and school readiness. We have been evaluating a simple finger puppet intervention that takes one minute and costs $1USD to deliver in the primary care setting to promote caregiver-infant interactions. We explored using developmental trajectories to determine later outcomes of our early intervention program by comparing trajectories to age 36 months to assess optimal intervention timing when delivered in early versus late infancy.MethodsThree cohorts were enrolled and given a puppet at 2 months (early intervention) and 6 or 12 months (late intervention). Child development was assessed using the Ages & Stages Questionnaires (ASQ-3), which were independently collected during well visits. Scanned ASQ-3 forms from 2 to 36 months were obtained retrospectively through the electronic medical record. To compare longitudinal scores at different ages, all raw scores were first converted to z-scores. Longitudinal mixed effects models examined the trajectories of participant ASQ-3 scores over time by comparing the average intercepts and slopes.ResultsOf 180 children enrolled, 172 (96%) completed 2 or more ASQ-3 questionnaires and were included in the analysis, with a mean of 4.9 and a total of 843 questionnaires. Most children (85%) were on government-sponsored insurance. There were no statistical differences comparing cohort intercepts, while early intervention had a significant difference in slope compared to late intervention for the Personal-Social domain (0.12, p=0.018), resulting in higher predicted scores at 36 months. Early compared to late intervention had a difference in slope approaching significance for Communication (0.14, p=0.056) and the combined non-motor score (0.33, p=0.052). There were no significant differences in slope for Problem Solving (0.05, p=0.48), Gross Motor (-0.009, p=0.84), Fine Motor (0.06, p=0.22), and total ASQ-3 (0.32, p=0.17) scores.ConclusionsFinger puppets may provide a simple and scalable way to encourage responsive caregiver-infant interactions promoting language and social-emotional development, especially when provided in early versus late infancy. Our trajectory analysis also demonstrates a useful and potentially cost-effective approach to evaluating long-term developmental outcomes of an early intervention.

Finger Puppets to Support Early Language Development: Effects of a Primary Care-Based Intervention in Infancy.

Verbally rich interactions beginning in early infancy are critical to future vocabulary development. We explored the effectiveness of introducing finger puppets in the primary care setting to support caregiver-infant interactions. The intervention cohort was given a puppet at 2 months, with high dosage defined as using the puppet daily in the first 2 weeks. At 6 months, a usual care cohort was enrolled, and outcome measures were collected for all participants. For the intervention, 92% (n = 70) of those eligible participated, and 80% (n = 56) completed the 6-month visit. For usual care, 78% (n = 60) of those eligible participated. In per-protocol analysis, overall cognitive stimulation (StimQ-I) (P = .04) and Parental Involvement in Developmental Advance subscale (P = .03) scores were higher for the high-dosage group (28.68, 5.16) than those for the low-dosage (24.81, 4.48) and usual care (24.15, 3.98) groups. Finger puppets may provide a low-cost and scalable way to support early language and child development.

Proactive or reactive? Neural oscillatory insight into the leader–follower dynamics of early infant–caregiver interaction

We know that infants' ability to coordinate attention with others toward the end of the first year is fundamental to language acquisition and social cognition. Yet, we understand little about the neural and cognitive mechanisms driving infant attention in shared interaction: do infants play a proactive role in creating episodes of joint attention? Recording electroencephalography (EEG) from 12-mo-old infants while they engaged in table-top play with their caregiver, we examined the communicative behaviors and neural activity preceding and following infant- vs. adult-led joint attention. Infant-led episodes of joint attention appeared largely reactive: they were not associated with increased theta power, a neural marker of endogenously driven attention, and infants did not increase their ostensive signals before the initiation. Infants were, however, sensitive to whether their initiations were responded to. When caregivers joined their attentional focus, infants showed increased alpha suppression, a pattern of neural activity associated with predictive processing. Our results suggest that at 10 to 12 mo, infants are not routinely proactive in creating joint attention episodes yet. They do, however, anticipate behavioral contingency, a potentially foundational mechanism for the emergence of intentional communication.

Gaze onsets during naturalistic infant-caregiver interaction associate with ‘sender’ but not ‘receiver’ neural responses, and do not lead to changes in inter-brain synchrony

Temporal coordination during infant-caregiver social interaction is thought to be crucial for supporting early language acquisition and cognitive development. Despite a growing prevalence of theories suggesting that increased inter-brain synchrony associates with many key aspects of social interactions such as mutual gaze, little is known about how this arises during development. Here, we investigated the role of mutual gaze onsets as a potential driver of inter-brain synchrony. We extracted dual EEG activity around naturally occurring gaze onsets during infant-caregiver social interactions in N = 55 dyads (mean age 12 months). We differentiated between two types of gaze onset, depending on each partners’ role. ‘Sender’ gaze onsets were defined at a time when either the adult or the infant made a gaze shift towards their partner at a time when their partner was either already looking at them (mutual) or not looking at them (non-mutual). ‘Receiver’ gaze onsets were defined at a time when their partner made a gaze shift towards them at a time when either the adult or the infant was already looking at their partner (mutual) or not (non-mutual). Contrary to our hypothesis we found that, during a naturalistic interaction, both mutual and non-mutual gaze onsets were associated with changes in the sender, but not the receiver’s brain activity and were not associated with increases in inter-brain synchrony above baseline. Further, we found that mutual, compared to non-mutual gaze onsets were not associated with increased inter brain synchrony. Overall, our results suggest that the effects of mutual gaze are strongest at the intra-brain level, in the ‘sender’ but not the ‘receiver’ of the mutual gaze.