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Neurodevelopmental disorders are on the rise worldwide, with diagnoses that detect derailment from typical milestones by 3 to 4.5 years of age. By then, the circuitry in the brain has already reached some level of maturation that inevitably takes neurodevelopment through a different course. There is a critical need then to develop analytical methods that detect problems much earlier and identify targets for treatment. We integrate data from multiple sources, including neonatal auditory brainstem responses (ABR), clinical criteria detecting autism years later in those neonates, and similar ABR information for young infants and children who also received a diagnosis of autism spectrum disorders, to produce the earliest known digital screening biomarker to flag neurodevelopmental derailment in neonates. This work also defines concrete targets for treatment and offers a new statistical approach to aid in guiding a personalized course of maturation in line with the highly nonlinear, accelerated neurodevelopmental rates of change in early infancy.

 

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.

 

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.

 

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.

 

From birth, human and nonhuman primates attend more to faces with direct gaze compared with averted gaze, and previous studies report that attention to the eyes is linked to the emergence of later social skills. Here, we explored whether early experiences influence attraction to eye contact in infant macaques by examining their attention to face pairs varying in their gaze direction across the first 13 weeks of life. Infants raised by human caretakers had limited conspecific interactions (nursery‐reared;N = 16) and were compared to infants raised in rich social environments (mother‐reared;N = 20). Both groups looked longer to faces and the eyes of direct compared to averted‐gaze faces. Looking to all faces and eyes also increased with age. Nursery‐reared infants did not display age‐associated increases in attention to direct‐gaze faces specifically, suggesting that, while there may be an initial preference for direct‐gaze faces from birth, social experiences may support its early development.

 

In humans, socioeconomic status (SES) has profound outcomes on socio‐emotional development and health. However, while much is known about theconsequencesofSES, little research has examined thepredictorsofSESdue to the longitudinal nature of such studies. We sought to explore whether interindividual differences in neonatal sociality, temperament, and early social experiences predicted juvenile social status in rhesus monkeys (Macaca mulatta), as a proxy forSESin humans. We performed neonatal imitation tests in infants’ first week of life and emotional reactivity assessments at 2 and 4 weeks of age. We examined whether these traits, as well as the rearing environment in the first 8 months of life (with the mother or with same‐aged peers only) and maternal social status predicted juvenile (2–3 years old) social status following the formation of peer social groups at 8 months. We found that infants who exhibited higher rates of neonatal imitation and newborn emotional reactivity achieved higher social status as juveniles, as did infants who were reared with their mothers, compared to infants reared with peers. Maternal social status was only associated with juvenile status for infant dyads reared in the same maternal group, indicating that relative social relationships were transferred through social experience. These results suggest that neonatal imitation and emotional reactivity may reflect ingrained predispositions toward sociality that predict later outcomes, and that nonnormative social experiences can alter socio‐developmental trajectories. Our results indicate that neonatal characteristics and early social experiences predict later social outcomes in adolescence, including gradients of social stratification.

 

Objective. Maternal stress is a psychological response to the demands of motherhood. A high level of maternal stress is a risk factor for maternal mental health problems, including depression and anxiety, as well as adverse infant socioemotional and cognitive outcomes. Yet, levels of maternal stress (i.e., levels of stress related to parenting) among low-risk samples are rarely studied longitudinally, particularly in the first year after birth. Design. We measured maternal stress in an ethnically diverse sample of low-risk, healthy U.S. mothers of healthy infants (N = 143) living in South Florida across six time points between 2 weeks and 14 months postpartum using the Parenting Stress Index-Short Form, capturing stress related to the mother, mother-infant interactions, and the infant. Results. Maternal distress increased as infants aged for mothers with more than one child, but not for first-time mothers whose distress levels remained low and stable across this period. Stress related to mother-infant dysfunctional interactions lessened over the first 8 months. Mothers’ stress about their infants’ difficulties decreased from 2 weeks to 6 months, and subsequently increased from 6 to 14 months. Conclusions. Our findings suggest that maternal stress is dynamic across the first year after birth. The current study adds to our understanding of typical developmental patterns in early motherhood and identifies potential domains and time points as targets for future interventions. 

Remote eye tracking with automated corneal reflection provides insights into the emergence and development of cognitive, social, and emotional functions in human infants and non-human primates. However, because most eye-tracking systems were designed for use in human adults, the accuracy of eye-tracking data collected in other populations is unclear, as are potential approaches to minimize measurement error. For instance, data quality may differ across species or ages, which are necessary considerations for comparative and developmental studies. Here we examined how the calibration method and adjustments to areas of interest (AOIs) of the Tobii TX300 changed the mapping of fixations to AOIs in a cross-species longitudinal study. We tested humans (N = 119) at 2, 4, 6, 8, and 14 months of age and macaques (Macaca mulatta; N = 21) at 2 weeks, 3 weeks, and 6 months of age. In all groups, we found improvement in the proportion of AOI hits detected as the number of successful calibration points increased, suggesting calibration approaches with more points may be advantageous. Spatially enlarging and temporally prolonging AOIs increased the number of fixation-AOI mappings, suggesting improvements in capturing infants’ gaze behaviors; however, these benefits varied across age groups and species, suggesting different parameters may be ideal, depending on the population studied. In sum, to maximize usable sessions and minimize measurement error, eye-tracking data collection and extraction approaches may need adjustments for the age groups and species studied. Doing so may make it easier to standardize and replicate eye-tracking research findings.