Newborn auditory brainstem response and sudden infant death syndrome.

Sudden infant death syndrome (SIDS)-the sudden and unexplained death of a seemingly healthy infant, <1 year old-may be associated with abnormalities in the brain regions that underlie breathing and arousal during sleep. While post-mortem studies suggest abnormalities in SIDS infants' brainstems, there are no studies of these infants' brainstem function before death. One way to assess the function of the brainstem is with auditory brainstem response (ABR), a routine hearing-screening method that noninvasively measures the brainstem's response to sound. We hypothesize that anomalies in newborns' ABR measures may predict SIDS. Indeed, previous studies identified abnormalities in ABR characteristics in small samples of near-miss SIDS infants hospitalized for infant apnea syndrome. However, there is a need to examine the ABRs of infants who died of SIDS. Therefore, in the current study, we propose integrating two secondary datasets to examine newborns' ABRs (N = 156,972), including those who later died of SIDS (n = ~42; .27 out of every 1000 infants), using existing archived records of neonatal ABR results from a sample of newborns born in Florida. We hypothesize that infants who die from SIDS are more likely than non-SIDS infants to have abnormal ABRs as newborns. Understanding the association between SIDS and ABR may facilitate more accurate identification of an infant's risk for SIDS at birth, enabling increased monitoring, which may facilitate interventions and improve survivorship.

The Combined Contributions of Newborn Stress and Parenting Stress on Toddler Language Development.

OBJECTIVE: To examine the longitudinal associations between newborn neurobehavioral stress signs, maternal parenting stress, and several indices of toddler language development. STUDY DESIGN: Participants include 202 mother-infant dyads (104 girls). We measured stress signs in neonates in the hospital at least 24 hours after birth using the Neonatal Intensive Care Unit Network Neurobehavioral Scale. At 7 months, parenting stress (competence, attachment, and role restriction) was assessed using the Parenting Stress Index. At 18 months, mothers completed the Communicative Development Inventories, which measured toddler gesturing, expressive vocabulary, and receptive vocabulary. Longitudinal path modeling was used to estimate associations between neonatal stress signs, parenting stress, and toddler language, and a model was generated for each language outcome. Child sex, birth weight, and family income were included as covariates. RESULTS: Infants who exhibited greater neurobehavioral stress signs at birth produced significantly fewer social-communicative gestures at 18 months of age. Among infants whose mothers reported low (but not high) levels of parenting stress during the first postnatal year, newborn stress signs were negatively associated with 18-month-olds' receptive vocabulary size. Neither newborn stress signs nor parenting stress were significantly related to toddler expressive vocabulary size. CONCLUSIONS: Our findings uncover a negative association between newborn stress signs and toddler gesturing. Furthermore, our results suggest that caregiver stress and neonatal stress signs interact to predict toddler receptive vocabulary. Taken together, these results demonstrate that some neonates who exhibit increased neurobehavioral stress signs may be at heightened risk for experiencing language difficulties. These children may benefit from additional support in infancy.

Infants' salivary oxytocin and positive affective reactions to people.

Oxytocin is a neuropeptide positively associated with prosociality in adults. Here, we studied whether infants' salivary oxytocin can be reliably measured, is developmentally stable, and is linked to social behavior. We longitudinally collected saliva from 62 U.S. infants (44 % female, 56 % Hispanic/Latino, 24 % Black, 18 % non-Hispanic White, 11 % multiracial) at 4, 8, and 14 months of age and offline-video-coded the valence of their facial affect in response to a video of a smiling woman. We also captured infants' affective reactions in terms of excitement/joyfulness during a live, structured interaction with a singing woman in the Early Social Communication Scales at 14 months. We detected stable individual differences in infants' oxytocin levels over time (over minutes and months) and in infants' positive affect over months and across contexts (video-based and in live interactions). We detected no statistically significant changes in oxytocin levels between 4 and 8 months but found an increase from 8 to 14 months. Infants with higher oxytocin levels showed more positive facial affect to a smiling person video at 4 months; however, this association disappeared at 8 months, and reversed at 14 months (i.e., higher oxytocin was associated with less positive facial affect). Infant salivary oxytocin may be a reliable physiological measure of individual differences related to socio-emotional development.

Maternal psychophysiology profiles: associations with prenatal opioid use, maternal emotion dysregulation, and newborn neurobehavior.

BACKGROUND: Opioid use among pregnant women has more than quadrupled over the past 20 years; however, comorbid risk factors such as emotion dysregulation confound the developmental consequences of prenatal opioid use. Maternal respiratory sinus arrhythmia (RSA) may help to disentangle the comorbid risk factors of prenatal emotion dysregulation and substance use and isolate their consequences on newborn neurobehavior. METHODS: We examined maternal RSA in response to a mild, infant-related stress task in pregnant people (N = 192; 30 on medications for opioid use disorder) recruited from hospitals and a specialty prenatal clinic for substance use disorder. RESULTS: Three latent profiles emerged based on maternal RSA reactivity. Mothers with RSA increasing (Profile 3; more nervous system dysregulation) had higher levels of emotion dysregulation than mothers with RSA decreasing (Profile 1; well-regulated nervous system responses) but were not more likely to use opioids. Additionally, RSA profiles were associated with newborn neurobehavior, including attention, regulation, handling, and arousal. CONCLUSIONS: Given the variability in opioid use across RSA profiles and profile associations with newborn neurodevelopment, future studies should examine protective factors in pregnant individuals using opioids who show more flexible RSA responses. IMPACT: Our study examined maternal psychophysiology and newborn outcomes in a unique population with high levels of emotion dysregulation and opioid use. Three profiles of maternal respiratory sinus arrythmia (RSA) reactivity were identified during pregnancy: decreasing, blunted, and increasing. The RSA increasing and blunted profiles were associated with higher emotion dysregulation than the decreasing profile. Most pregnant people on medications for opioid use disorder (65%) were grouped into the blunted profile, suggesting they might be more at risk for dysregulated RSA reactivity. Differences in RSA profiles were associated with newborn outcomes, with increasing and blunted RSA predicting more newborn neurobehavioral dysregulation.

Infection detection in faces: Children's development of pathogen avoidance.

This study examined the development of children's avoidance and recognition of sickness using face photos from people with natural, acute, contagious illness. In a U.S. sample of fifty-seven 4- to 5-year-olds (46% male, 70% White), fifty-two 8- to 9-year-olds (26% male, 62% White), and 51 adults (59% male, 61% White), children and adults avoided and recognized sick faces (ds ranged from 0.38 to 2.26). Both avoidance and recognition improved with age. Interestingly, 4- to 5-year-olds' avoidance of sick faces positively correlated with their recognition, suggesting stable individual differences in these emerging skills. Together, these findings are consistent with a hypothesized immature but functioning and flexible behavioral immune system emerging early in development. Characterizing children's sickness perception may help design interventions to improve health.

From prenatal maternal anxiety and respiratory sinus arrhythmia to toddler internalizing problems: The role of infant negative affectivity.

Prenatal maternal anxiety is considered a risk factor for the development of child internalizing problems. However, little is known about potential mechanisms that account for these associations. The current study examined whether prenatal maternal anxiety was indirectly associated with toddler internalizing problems via prenatal maternal physiology and infant negative affectivity. We examined these associations in a longitudinal study of 162 expectant mothers from their third trimester until 18 months postpartum. Path analyses showed that higher prenatal anxiety was associated with higher infant negative affectivity at 7 months, which in turn was associated with higher toddler internalizing problems at 18 months. Prenatal anxiety was not indirectly associated with child outcomes via baseline or task-evoked respiratory sinus arrhythmia (RSA) in response to an infant cry while pregnant. However, pregnant women with greater decreases in task-evoked RSA had toddlers with greater internalizing problems, which was mediated by infant negative affectivity at 7 months. Findings suggest that prenatal anxiety and RSA reactivity to an infant cry may be independent risk factors for the development of infant negative affectivity, which in turn increases risk for toddler internalizing problems. These findings contribute to a growing literature on mechanisms that underlie intergenerational transmission of internalizing problems.

Emerging Adults Mirror Infants' Emotions and Yawns.

Infants' nonverbal expressions-a broad smile or a sharp cry-are powerful at eliciting reactions. Although parents' reactions to their own infants' expressions are relatively well understood, here we studied whether adults more generally exhibit behavioral and physiological reactions to unfamiliar infants producing various expressions. We recruited U.S. emerging adults (N = 84) prior to parenthood, 18-25 years old, 68% women, ethnically (20% Hispanic/Latino) and racially (7% Asian, 13% Black, 1% Middle Eastern, 70% White, 8% multiracial) diverse. They observed four 80-s audio-video clips of unfamiliar 2- to 6-month-olds crying, smiling, yawning, and sitting calmly (emotionally neutral control). Each compilation video depicted 9 different infants (36 clips total). We found adults mirrored behaviorally and physiologically: more positive facial expressions to infants smiling, and more negative facial expressions and pupil dilation-indicating increases in arousal-to infants crying. Adults also yawned more and had more pupil dilation when observing infants yawning. Together, these findings suggest that even nonparent emerging adults are highly sensitive to unfamiliar infants' expressions, which they naturally "catch" (i.e., behaviorally and physiologically mirror), even without instructions. Such sensitivity may have-over the course of humans' evolutionary history-been selected for, to facilitate adults' processing of preverbal infants' expressions to meet their needs.

Latent Class Analysis of Prenatal Substance Exposure and Child Behavioral Outcomes.

OBJECTIVES: To predict behavioral disruptions in middle childhood, we identified latent classes of prenatal substance use. STUDY DESIGN: As part of the Environmental influences on Child Health Outcomes Program, we harmonized prenatal substance use data and child behavior outcomes from 2195 women and their 6- to 11-year-old children across 10 cohorts in the US and used latent class-adjusted regression models to predict parent-rated child behavior. RESULTS: Three latent classes fit the data: low use (90.5%; n = 1986), primarily using no substances; licit use (6.6%; n = 145), mainly using nicotine with a moderate likelihood of using alcohol and marijuana; and illicit use (2.9%; n = 64), predominantly using illicit substances along with a moderate likelihood of using licit substances. Children exposed to primarily licit substances in utero had greater levels of externalizing behavior than children exposed to low or no substances (P = .001, d = .64). Children exposed to illicit substances in utero showed small but significant elevations in internalizing behavior than children exposed to low or no substances (P < .001, d = .16). CONCLUSIONS: The differences in prenatal polysubstance use may increase risk for specific childhood problem behaviors; however, child outcomes appeared comparably adverse for both licit and illicit polysubstance exposure. We highlight the need for similar multicohort, large-scale studies to examine childhood outcomes based on prenatal substance use profiles.

Behavioral and physiological sensitivity to natural sick faces.

The capacity to rapidly detect and avoid sick people may be adaptive. Given that faces are reliably available, as well as rapidly detected and processed, they may provide health information that influences social interaction. Prior studies used faces that were manipulated to appear sick (e.g., editing photos, inducing inflammatory response); however, responses to naturally sick faces remain largely unexplored. We tested whether adults detected subtle cues of genuine, acute, potentially contagious illness in face photos compared to the same individuals when healthy. We tracked illness symptoms and severity with the Sickness Questionnaire and Common Cold Questionnaire. We also checked that sick and healthy photos were matched on low-level features. We found that participants (N = 109) rated sick faces, compared to healthy faces, as sicker, more dangerous, and eliciting more unpleasant feelings. Participants (N = 90) rated sick faces as more likely to be avoided, more tired, and more negative in expression than healthy faces. In a passive-viewing eye-tracking task, participants (N = 50) looked longer at healthy than sick faces, especially the eye region, suggesting people may be more drawn to healthy conspecifics. When making approach-avoidance decisions, participants (N = 112) had greater pupil dilation to sick than healthy faces, and more pupil dilation was associated with greater avoidance, suggesting elevated arousal to threat. Across all experiments, participants' behaviors correlated with the degree of sickness, as reported by the face donors, suggesting a nuanced, fine-tuned sensitivity. Together, these findings suggest that humans may detect subtle threats of contagion from sick faces, which may facilitate illness avoidance. By better understanding how humans naturally avoid illness in conspecifics, we may identify what information is used and ultimately improve public health.

Social motivation predicts gaze following between 6 and 14 months.

Infants vary in their ability to follow others' gazes, but it is unclear how these individual differences emerge. We tested whether social motivation levels in early infancy predict later gaze following skills. We longitudinally tracked infants' (N = 82) gazes and pupil dilation while they observed videos of a woman looking into the camera simulating eye contact (i.e., mutual gaze) and then gazing toward one of two objects, at 2, 4, 6, 8, and 14 months of age. To improve measurement validity, we used confirmatory factor analysis to combine multiple observed measures to index the underlying constructs of social motivation and gaze following. Infants' social motivation-indexed by their speed of social orienting, duration of mutual gaze, and degree of pupil dilation during mutual gaze-was developmentally stable and positively predicted the development of gaze following-indexed by their proportion of time looking to the target object, first object look difference scores, and first face-to-object saccade difference scores-from 6 to 14 months of age. These findings suggest that infants' social motivation likely plays a role in the development of gaze following and highlight the use of a multi-measure approach to improve measurement sensitivity and validity in infancy research.

Infant temperamental fear, pupil dilation, and gaze aversion from smiling strangers.

In childhood, higher levels of temperamental fear-an early-emerging proclivity to distress in the face of novelty-are associated with lower social responsivity and greater social anxiety. While the early emergence of temperamental fear in infancy is poorly understood, it is theorized to be driven by individual differences in reactivity and self-regulation to novel stimuli. The current study used eye tracking to capture infants' (N = 124) reactions to a video of a smiling stranger-a common social encounter-including infant gaze aversions from the stranger's face (indexing arousal regulation) and pupil dilation (indexing physiological reactivity), longitudinally at 2, 4, 6, and 8 months of age. Multilevel mixed-effects models indicated that more fearful infants took more time to look away from a smiling stranger's face than less fearful infants, suggesting that high-fear infants may have slower arousal regulation. At 2 and 4 months, more fearful infants also exhibited greater and faster pupil dilation before gaze aversions, consistent with greater physiological reactivity. Together, these findings suggest that individual differences in infants' gaze aversions and pupil dilation can index the development of fearful temperament in early infancy, facilitating the identification of, and interventions for, risk factors to social disruptions.

Superior Detection of Faces in Male Infants at 2 Months.

Females generally attend more to social information than males; however, little is known about the early development of these sex differences. With eye tracking, 2-month olds' (N = 101; 44 females) social orienting to faces was measured within four-item image arrays. Infants were more likely to detect human faces compared to objects, suggesting a functional face detection system. Unexpectedly, males looked longer at human faces than females, and only males looked faster and longer at human faces compared to objects. Females, in contrast, looked less at human faces relative to animal faces and objects, appearing socially disinterested. Notably, this is the first report of a male face detection advantage at any age. These findings suggest a unique stage in early infant social development.

Face detection in 2- to 6-month-old infants is influenced by gaze direction and species.

Humans detect faces efficiently from a young age. Face detection is critical for infants to identify and learn from relevant social stimuli in their environments. Faces with eye contact are an especially salient stimulus, and attention to the eyes in infancy is linked to the emergence of later sociality. Despite the importance of both of these early social skills-attending to faces and attending to the eyes-surprisingly little is known about how they interact. We used eye tracking to explore whether eye contact influences infants' face detection. Longitudinally, we examined 2-, 4-, and 6-month-olds' (N = 65) visual scanning of complex image arrays with human and animal faces varying in eye contact and head orientation. Across all ages, infants displayed superior detection of faces with eye contact; however, this effect varied as a function of species and head orientation. Infants were more attentive to human than animal faces and were more sensitive to eye and head orientation for human faces compared to animal faces. Unexpectedly, human faces with both averted heads and eyes received the most attention. This pattern may reflect the early emergence of gaze following-the ability to look where another individual looks-which begins to develop around this age. Infants may be especially interested in averted gaze faces, providing early scaffolding for joint attention. This study represents the first investigation to document infants' attention patterns to faces systematically varying in their attentional states. Together, these findings suggest that infants develop early, specialized functional conspecific face detection.

Human and monkey infant attention to dynamic social and nonsocial stimuli.

The present study explored behavioral norms for infant social attention in typically developing human and nonhuman primate infants. We examined the normative development of attention to dynamic social and nonsocial stimuli longitudinally in macaques (Macaca mulatta) at 1, 3, and 5 months of age (N = 75) and humans at 2, 4, 6, 8, and 13 months of age (N = 69) using eye tracking. All infants viewed concurrently played silent videos-one social video and one nonsocial video. Both macaque and human infants were faster to look to the social than the nonsocial stimulus, and both species grew faster to orient to the social stimulus with age. Further, macaque infants' social attention increased linearly from 1 to 5 months. In contrast, human infants displayed a nonlinear pattern of social interest, with initially greater attention to the social stimulus, followed by a period of greater interest in the nonsocial stimulus, and then a rise in social interest from 6 to 13 months. Overall, human infants looked longer than macaque infants, suggesting humans have more sustained attention in the first year of life. These findings highlight potential species similarities and differences, and reflect a first step in establishing baseline patterns of early social attention development.

Face detection in infants and adults: Effects of orientation and color.

Humans rapidly locate and recognize human faces, even in complex environments. In the current study, we explored some of the social and perceptual features of faces that may contribute to this ability. We measured infant and adult attention to complex, heterogeneous image arrays containing human and animal faces. Arrays were upright or inverted 180° and in color or grayscale. Infants, aged 3-5 months (n = 51) and 10-11 months (n = 34), viewed 6-item arrays (Experiment 1), whereas adults (n = 120) searched 64-item arrays (Experiment 2). We found that 3- to 5-month-olds already displayed strong own-species biases in face detection-in attention capture, attention holding, and overall detection-suggesting a surprisingly early specialization for human face detection. Furthermore, this remarkable ability was robust, evident even when color and orientation were disrupted, and grew stronger with age. Interestingly, infants' face detection was reduced by low-level manipulations in a species-specific way, negatively affecting only animal face detection but not affecting human face detection. In contrast, adults' face detection efficiency was equally reduced by low-level manipulations across species, suggesting potential age differences in own-species face detection. For infants, social relevance (species) may play a more important role than low-level perceptual features, ensuring that infants attend to, connect with, and learn from the people around them. Efficient human face detection during infancy may reflect the uniqueness of own-species faces as a category, perhaps due to their social relevance.

Animal studies help clarify misunderstandings about neonatal imitation.

Empirical studies are incompatible with the proposal that neonatal imitation is arousal driven or declining with age. Nonhuman primate studies reveal a functioning brain mirror system from birth, developmental continuity in imitation and later sociability, and the malleability of neonatal imitation, shaped by the early environment. A narrow focus on arousal effects and reflexes may grossly underestimate neonatal capacities.

A protocol for enhancing the diagnostic accuracy and predictive validity of neonatal opioid withdrawal syndrome: The utility of non-invasive clinical markers.

Every 15 minutes in the US, an infant exposed to opioids is born. Approximately 50% of these newborns will develop Neonatal Opioid Withdrawal Syndrome (NOWS) within 5 days of birth. It is not known which infants will develop NOWS, therefore, the current hospital standard-of-care dictates a 96-hour observational hold. Understanding which infants will develop NOWS soon after birth could reduce hospital stays for infants who do not develop NOWS and decrease burdens on hospitals and clinicians. We propose noninvasive clinical indicators of NOWS, including newborn neurobehavior, autonomic biomarkers, prenatal substance exposures, and socioeconomic environments. The goals of this protocol are to use these indicators shortly after birth to differentiate newborns who will be diagnosed with NOWS from those who will have mild/no withdrawal, to determine if the indicators predict development at 6 and 18 months of age, and to increase NOWS diagnostic sensitivity for earlier, more accurate diagnoses.

A bioecological longitudinal study of depressive symptoms from pregnancy to 36 months postpartum.

PURPOSE: Depressive symptoms during the perinatal period have broad and enduring health implications for birthing parents and their offspring. Rising prevalence rates of perinatal depression highlight the need for research examining factors influencing depressive symptoms during pregnancy, and trajectories during the early postnatal period. Grounded in bioecological systems theory, this longitudinal multimethod study examined whether prenatal bioecological factors predict depressive symptoms from pregnancy to 36 months postpartum. METHODS: Participants were 162 pregnant individuals, oversampled for high emotion dysregulation, who completed a life stress interview and physiological assessment during the 3rd trimester and a self-report measure of depression at five time-points (3rd trimester, within 48 h of birth, 7, 18, and 36 months postpartum). Multilevel models were used to test study aims. RESULTS: Participants exhibited the highest levels of depressive symptoms at 3rd trimester, and substantial variability in depressive symptom trajectories over time. Lower resting respiratory sinus arrhythmia (RSA), an index of parasympathetic nervous system functioning, in the 3rd trimester was associated with higher concurrent depressive symptoms. Higher levels of stress related to partner relationships, finances, and health were concurrently associated with more depressive symptoms during pregnancy and decreases in depressive symptoms over time. Specifically, depressive symptoms decreased only for individuals who reported high levels of stress during pregnancy. LIMITATIONS: Although grounded in bioecological systems theory, this study did not assess the macrosystem. CONCLUSIONS: Results of this study underscore the importance of multilevel predictors of perinatal health and highlights potential targets for preventing depression and promoting well-being during the perinatal transition.

Examining implications of the developmental timing of maternal trauma for prenatal and newborn outcomes.

Separate literatures have demonstrated that mothers' experiences with trauma during childhood or pregnancy are associated with maternal prenatal health risks, adverse childbirth outcomes, and offspring internalizing and externalizing disorders. These literatures largely align with the intergenerational transmission or fetal programming frameworks, respectively. However, few studies have tested the effects of maternal childhood and prenatal trauma simultaneously on mothers' and infants' health outcomes, and no studies have examined these effects on newborn neurobehavioral outcomes. Thus, in the present study, we examined how the developmental timing of pregnant women's traumatic life experiences associated with their physical health and psychopathology (Aim 1) as well as their newborns' birth and neurodevelopmental outcomes (Aim 2; for pre-registered aims and hypotheses, see https://osf.io/ygnre/?view_only=cbe17d0ac7f24af5a4d3e37e24eebead). One hundred and fifty-two 3rd trimester pregnant women (Mage = 29 years; 17.1% Hispanic/Latina) completed measures of trauma history and psychopathology. Then, 24-48 h after birth, trained clinicians conducted newborn neurobehavioral exams (n = 118 newborns; 52.6% female). Results indicated that lifetime traumatic experiences associated with multiple prenatal maternal health outcomes, including depression, anxiety, emotion dysregulation, and pregnancy complications. Pregnant women's experiences with childhood trauma, but not adulthood or prenatal trauma, predicted higher neurobehavioral attention scores among female newborns. Our discussion highlights the importance of considering the developmental timing of maternal trauma on perinatal outcomes and contextualizes our findings within the intergenerational transmission and fetal programming literatures. DATA AVAILABILITY: Data pertaining to R01MH119070 (MPIs Crowell & Conradt) and that support these findings are uploaded to the NIMH repository.

Social touch alters newborn monkey behavior.

In humans, infants respond positively to slow, gentle stroking-processed by C-tactile (CT) nerve fibers-by showing reductions in stress and increases in eye contact, smiling, and positive vocalizations. More frequent maternal touch is linked to greater activity and connectivity strength in social brain regions, and increases children's attention to and learning of faces. It has been theorized that touch may prime children for social interactions and set them on a path towards healthy social cognitive development. However, less is known about the effects of touch on young infants' psychological development, especially in the newborn period, a highly sensitive period of transition with rapid growth in sensory and social processing. It remains untested whether newborns can distinguish CT-targeted touch from other types of touch, or whether there are benefits of touch for newborns' social, emotional, or cognitive development. In the present study, we experimentally investigated the acute effects of touch in newborn monkeys, a common model for human social development. Rhesus macaques (Macaca mulatta), like humans, are highly social, have complex mother-infant interactions with frequent body contact for the first weeks of life, making them an excellent model of infant sociality. Infant monkeys in the present study were reared in a neonatal nursery, enabling control over their early environment, including all caregiver interactions. One-week-old macaque infants (N = 27) participated in three 5-minute counter-balanced caregiver interactions, all with mutual gaze: stroking head and shoulders (CT-targeted touch), stroking palms of hands and soles of feet (Non-CT touch), or no stroking (No-touch). Immediately following the interaction, infants watched social and nonsocial videos and picture arrays including faces and objects, while we tracked their visual attention with remote eye tracking. We found that, during the caregiver interactions, infants behaved differently while being touched compared to the no-touch condition, irrespective of the body part touched. Most notably, in both touch conditions, infants exhibited fewer stress-related behaviors-self-scratching, locomotion, and contact time with a comfort object-compared to when they were not touched. Following CT-targeted touch, infants were faster to orient to the picture arrays compared to the other interaction conditions, suggesting CT-targeted touch may activate or prime infants' attentional orienting system. In the No-touch condition infants attended longer to the nonsocial compared to the social video, possibly reflecting a baseline preference for nonsocial stimuli. In contrast, in both touch conditions, infants' looked equally to the social and nonsocial videos, suggesting that touch may influence the types of visual stimuli that hold infants' attention. Collectively, our results reveal that newborn macaques responded positively to touch, and touch appeared to influence some aspects of their subsequent attention, although we found limited evidence that these effects are mediated by CT fibers. These findings suggest that newborn touch may broadly support infants' psychological development, and may have early evolutionary roots, shared across primates. This study illustrates the unique insight offered by nonhuman primates for exploring early infant social touch, revealing that touch may positively affect emotional and attentional development as early as the newborn period.