Physiological arousal predicts gaze following in infants

Infant Gaze Following Is Stable Across Markedly Different Cultures and Resilient to Family Adversities Associated With War and Climate Change

Gaze following in infancy allows triadic social interactions and a comprehension of other individuals and their surroundings. Despite its importance for early development, its ontology is debated, with theories suggesting that gaze following is either a universal core capacity or an experience-dependent learned behavior. A critical test of these theories among 809 nine-month-olds from Africa (Uganda and Zimbabwe), Europe (Sweden), and Asia (Bhutan) demonstrated that infants follow gaze to a similar degree regardless of environmental factors such as culture, maternal well-being (postpartum depression, well-being), or traumatic family events (related to war and/or climate change). These findings suggest that gaze following may be a universal, experience-expectant process that is resilient to adversity and similar across a wide range of human experiences-a core foundation for social development.

Revisiting the Object-Processing Paradigm in the Study of Gaze Cues: What Two Decades of Research Have Taught Us About Infant Social Learning

Infants are highly sensitive to social stimuli from early on in ontogeny. Social cues, including others' gaze, not only capture and guide infants' attention, but also modulate the efficiency in which the infant (brain) encodes and recognizes information. Over the last two decades, the novelty preference based object-processing paradigm has been instrumental in investigating this phenomenon experimentally. This paper offers a comprehensive review and critical evaluation of methodological aspects and empirical findings from previous research using this paradigm to study the influence of (non-)social cues on infants' object processing. We highlight the critical role of methodological details and discuss influential factors such as eye contact, infants' object-directed attention, naturalistic environments, and potential neural correlates associated with enhanced object encoding. A comprehensive review table summarizes key methodological details from previous studies to assist researchers in making informed decisions when designing future studies. We conclude that the object-processing paradigm has proven to be an effective method with high potential for future research disentangling the influence of fine-grained factors on infants' object memory.

Early Recognition and Intervention in SIBlingS at High Risk for Neurodevelopment Disorders (ERI-SIBS): a controlled trial of an innovative and ecological intervention for siblings of children with autism spectrum disorder

Background

It has been widely demonstrated that siblings of children with autism spectrum disorder (ASD) have an increased risk of abnormal developmental trajectories. In response to this, early recognition protocols have been developed worldwide, aiming to promote early interventions that can positively impact the neurodevelopment of this population. This paper presents the protocol of a controlled trial: ERI-SIBS (Early Recognition and Intervention in SIBlingS at High Risk for Neurodevelopment Disorders) is an innovative and ecological early recognition and intervention program designed specifically for siblings of children with ASD.

Methods

We aim to recruit siblings at low risk and high risk of neurodevelopmental disorders. Based on clinical evaluation at T0, we will allocate the infants into three groups: Group 1, infants at low risk without any signs of neurodevelopmental disorders; Group 2, infants at high risk without any signs of neurodevelopmental disorders; Group 3: infants at low or high risk with signs suggestive of neurodevelopmental disorders. Children of Group 2 will undergo Active Monitoring (one 90 min session once a month for 6 months), while children of Group 3 will undergo Early Intervention (one 90 min session once a week for 6 months). In both cases, the ERI-SIBS contents are based on a multidimensional and naturalistic approach and always involve caregivers. All recruited children will be evaluated at three different time points (T0 within the 8 months of life of the child, T1 after 6 months and T2 after 12 months) using behavioural, technological, and biological techniques to assess infants' neurodevelopmental functions, parent-infant interaction, and early ASD markers.

Discussion

The ERI-SIBS study will expand knowledge regarding the impact of early intervention on families of infants at risk of neurodevelopmental disorders for the presence of a child with a diagnosis of ASD. The study will have the potential to significantly contribute to future research and the scientific and clinical debate on the best way to implement early intervention in at-risk populations.

Clinical Trial Registration

Clinicaltrials.gov identifier (NCT06512649).

The development of social learning: from pedagogical cues to selective learning

Learning new information from others, called social learning, is one of the most fundamental types of learning from infancy. Developmental studies show that infants likely engage in social learning situations selectively and that social learning facilitates infant information processing. In this paper, we summarize how social learning functions support human learning from infancy focusing on two aspects of social learning; pedagogical learning and selective learning. We also provide an overview of the developmental process of social learning based on the findings of developmental research. This review suggests that the learning facilitation effects of pedagogical learning decrease with development, while the facilitation effects of selective learning are observed even in older ages. The differences in these learning facilitation effects are considered to be due to the differences in the utility of learning in uncertain environments. The findings of the studies imply the unique nature of human social learning and the critical role of social interactions in cognitive development. Understanding the development of social learning provides valuable insights into how infants learn and adapt in complex social environments.

Remote, tablet-based assessment of gaze following: a nationwide infant twin study

Introduction

Much of our understanding of infant psychological development relies on an in-person, laboratory-based assessment. This limits research generalizability, scalability, and equity in access. One solution is the development of new, remotely deployed assessment tools that do not require real-time experimenter supervision.

Methods

The current nationwide (Sweden) infant twin study assessed participants remotely via their caregiver's tablets (N = 104, ages 3 to 17 months). To anchor our findings in previous research, we used a gaze-following task where experimental and age effects are well established.

Results

Closely mimicking results from conventional eye tracking, we found that a full head movement elicited more gaze following than isolated eye movements. Furthermore, predictably, we found that older infants followed gaze more frequently than younger infants. Finally, while we found no indication of genetic contributions to gaze-following accuracy, the latency to disengage from the gaze cue and orient toward a target was significantly more similar in monozygotic twins than in dizygotic twins, an indicative of heritability.

Discussion

Together, these results highlight the potential of remote assessment of infants' psychological development, which can improve generalizability, inclusion, and scalability in developmental research.

Action value calculations in social context from infancy

Infants adaptively modulate their social behaviours, such as gaze-following, to social context. We propose that such modulations are based on infants' social decision-making, to achieve the most valuable outcome. We propose an 'action value calculator model', which formulates the cognitive mechanisms underlying, and the development of, the decision-making process during interactions.

Gaze following: A socio-cognitive skill rooted in deep time

Social gaze has received much attention in social cognition research in both human and non-human animals. Gaze following appears to be a central skill for acquiring social information, such as the location of food and predators, but can also draw attention to important social interactions, which in turn promotes the evolution of more complex socio-cognitive processes such as theory of mind and social learning. In the past decades, a large number of studies has been conducted in this field introducing differing methodologies. Thereby, various factors influencing the results of gaze following experiments have been identified. This review provides an overview of the advances in the study of gaze following, but also highlights some limitations within the research area. The majority of gaze following studies on animals have focused on primates and canids, which limits evolutionary interpretations to only a few and closely related evolutionary lineages. This review incorporates new insights gained from previously understudied taxa, such as fishes, reptiles, and birds, but it will also provide a brief outline of mammal studies. We propose that the foundations of gaze following emerged early in evolutionary history. Basic, reflexive co-orienting responses might have already evolved in fishes, which would explain the ubiquity of gaze following seen in the amniotes. More complex skills, such as geometrical gaze following and the ability to form social predictions based on gaze, seem to have evolved separately at least two times and appear to be correlated with growing complexity in brain anatomy such as increased numbers of brain neurons. However, more studies on different taxa in key phylogenetic positions are needed to better understand the evolutionary history of this fundamental socio-cognitive skill.

Investigating the effect of synchronized movement on toddlers' word learning

The effect of interpersonal behavioral synchrony on children's behavior is an emerging field rich with research potential. While studies demonstrate its effect on affiliative and prosocial outcomes, the role of synchronized movement on children's specific learning outcomes has not yet been investigated experimentally. One possibility is that synchrony, as a coordinated social activity, encourages perceived social bonds, leading to heightened attention, and better information retention. Equally likely is that physiological, rather than social learning, mechanisms mediate the effect, given the previously demonstrated role of autonomic arousal in attentional fluctuations, cognitive engagement, problem solving, exploration, and curiosity. The present study investigated the behavioral and physiological effects of synchrony conceptualized as induced, interpersonal, behavioral, movement-based interaction, on word learning in 2.5-year-old children. In a laboratory experiment, toddlers engaged in either a synchronous or an asynchronous movement-based interaction with an adult experimenter while listening to an upbeat children's song. After the (a)synchronous movement episode, the same experimenter engaged children in a word learning task. During the (a)synchrony and learning phases, children's physiological arousal was continuously recorded, resulting in heart rate and skin conductance response measures. Following a caregiver-child free play break, children were tested on their novel word retention. The results indicated that children learned novel labels at equal rates during the learning phase in both conditions, and their retention at test did not differ between conditions: although above chance retention of novel labels was found only following the synchronous, but not the asynchronous episode, the cross-episode comparisons did not reach statistical significance. Physiological arousal indices following the (a)synchrony episode did not differ between conditions and did not predict better word learning, although skin conductance response was higher during the learning than the movement episode. This study contributes to our understanding of the underlying cognitive and physiological mechanisms of interpersonal behavioral synchrony in the knowledge acquisition domain and paves the way to future investigations.

Social reward anticipation in infants as revealed by event-related potentials

Infants engage in gaze interaction from the early stage of life. Emerging studies suggest that infants may expect social reward of shared attention before looking to the same object with another person. However, it was unknown about the neural responses during the anticipation of social rewards before shared attention in infants. We tested infants' reward anticipations in the gaze cueing situation measured by event-related potentials in the social association learning task. Six- to ten-month-old infants (N = 20) repeatedly observed that a female predictively looked toward the animation position (valid condition) or another female looking away from the animation (invalid condition). It was posited that infants could learn associations between female faces and the event of shared attention. The results showed that the stimulus preceding negativity which reflects reward anticipation before the animation presentation was elicited in the second half of the learning phases in the valid condition. Additionally, after the presentation of the face, N290 was greater in the second half of the learning phase than in the first half in the valid condition. These results suggest that infants can anticipate social reward from gaze cues, and learning the gaze cueing validity may affect not only reward anticipation but face perception.

Physiological arousal explains infant gaze following in various social contexts

Gaze following (GF) is fundamental to central aspects of human sociocognitive development, such as acquiring language and cultural learning. Studies have shown that infant GF is not a simple reflexive orientation to an adult's eye movement. By contrast, infants adaptively modulate GF behaviour depending on the social context. However, arguably, the neurophysiological mechanisms underlying contextual modulation of GF remain somewhat unexplored. In this study, we tested the proposition about whether the contextual modulation of infant GF is mediated by the infant's heart rate (HR), which indicates the infant's physiological arousal. Forty-one 6- to 9-month-old infants participated in this study, and infants observed either a reliable face, which looked towards the location of an object, or an unreliable face, which looked away from the location of an object. Thereafter, the infants watched a video of the same model making eye contact or not making any ostensive signals, before shifting their gaze towards one of the two objects. We revealed that reliability and eye contact acted independently to increase HR, which then fully mediates the effects of these social cues on the frequency of GF. Results suggest that each social cue independently enhances physiological arousal, which then accumulatively predicts the likelihood of infant GF behaviour.

Physiological arousal explains infant gaze following in various social contexts

Gaze following (GF) is fundamental to central aspects of human sociocognitive development, such as acquiring language and cultural learning. Studies have shown that infant GF is not a simple reflexive orientation to an adult's eye movement. By contrast, infants adaptively modulate GF behaviour depending on the social context. However, arguably, the neurophysiological mechanisms underlying contextual modulation of GF remain somewhat unexplored. In this study, we tested the proposition about whether the contextual modulation of infant GF is mediated by the infant's heart rate (HR), which indicates the infant's physiological arousal. Forty-one 6- to 9-month-old infants participated in this study, and infants observed either a reliable face, which looked towards the location of an object, or an unreliable face, which looked away from the location of an object. Thereafter, the infants watched a video of the same model making eye contact or not making any ostensive signals, before shifting their gaze towards one of the two objects. We revealed that reliability and eye contact acted independently to increase HR, which then fully mediates the effects of these social cues on the frequency of GF. Results suggest that each social cue independently enhances physiological arousal, which then accumulatively predicts the likelihood of infant GF behaviour.

Nonverbal Action Interpretation Guides Novel Word Disambiguation in 12-Month-Olds

Whether young infants can exploit sociopragmatic information to interpret new words is a matter of debate. Based on findings and theories from the action interpretation literature, we hypothesized that 12-month-olds should distinguish communicative object-directed actions expressing reference from instrumental object-directed actions indicative of one's goals, and selectively use the former to identify referents of novel linguistic expressions. This hypothesis was tested across four eye-tracking experiments. Infants watched pairs of unfamiliar objects, one of which was first targeted by either a communicative action (e.g., pointing) or an instrumental action (e.g., grasping) and then labeled with a novel word. As predicted, infants fast-mapped the novel words onto the targeted objects after pointing (Experiments 1 and 4) but not after grasping (Experiment 2) unless the grasping action was preceded by an ostensive signal (Experiment 3). Moreover, whenever infants mapped a novel word onto the object indicated by a communicative action, they tended to map a different novel word onto the distractor object, displaying a mutual exclusivity effect. This reliance on nonverbal action interpretation in the disambiguation of novel words indicates that sociopragmatic inferences about reference likely supplement associative and statistical learning mechanisms from the outset of word learning.

Pupil dilation predicts modulation of direct gaze on action value calculations

Perceiving direct gaze facilitates social cognition and behaviour. We hypothesized that direct gaze modulates decision-making, particularly calculations of action values. To test our hypothesis, we used the reinforcement learning paradigm in situations with or without direct gaze. Forty adults were recruited and participated in pupil size measurements and a two-armed bandit task. The task was conducted with 70% and 30% reward probabilities for each option. During the task, a female showing the Direct Gaze (DG) or Closed Eyes (CE) condition was presented from the start of each trial. The results showed that behavioural bias to choices with 70% reward probability increased more in the DG condition than in the CE condition and the expected reward value. This bias to choices with 70% reward in the DG condition was predicted by pupil dilation to DG. These results suggest that participants over-evaluated the expected reward value in the DG condition, and this DG effect may be related to subjective expectations of rewarding events indexed by pupil dilations. It is considered that perceiving direct gaze is a driver of reward expectations that modulate action value calculations and then cognitive processing and behaviours are facilitated.

The understanding of congruent and incongruent referential gaze in 17-month-old infants: an eye-tracking study comparing human and robot

Several studies have shown that the human gaze, but not the robot gaze, has significant effects on infant social cognition and facilitate social engagement. The present study investigates early understanding of the referential nature of gaze by comparing-through the eye-tracking technique-infants' response to human and robot's gaze. Data were acquired on thirty-two 17-month-old infants, watching four video clips, where either a human or a humanoid robot performed an action on a target. The agent's gaze was either turned to the target (congruent) or opposite to it (incongruent). The results generally showed that, independent of the agent, the infants attended longer at the face area compared to the hand and target. Additionally, the effect of referential gaze on infants' attention to the target was greater when infants watched the human compared to the robot's action. These results suggest the presence, in infants, of two distinct levels of gaze-following mechanisms: one recognizing the other as a potential interactive partner, the second recognizing partner's agency. In this study, infants recognized the robot as a potential interactive partner, whereas ascribed agency more readily to the human, thus suggesting that the process of generalizability of gazing behaviour to non-humans is not immediate.

Learning Process of Gaze Following: Computational Modeling Based on Reinforcement Learning

Many studies have explored factors which influence gaze-following behavior of young infants. However, the results of empirical studies were inconsistent, and the mechanism underlying the contextual modulation of gaze following remains unclear. In order to provide valuable insight into the mechanisms underlying gaze following, we conducted computational modeling using Q-learning algorithm and simulated the learning process of infant gaze following to suggest a feasible model. In Experiment 1, we simulated how communicative cues and infant internal states affect the learning process of gaze following. The simulation indicated that the model in which communicative cues enhance infant internal states is the most feasible to explain the infant learning process. In Experiment 2, we simulated how individual differences in motivation for communication affect the learning process. The results showed that low motivation for communication can delay the learning process and decrease the frequency of gaze following. These simulations suggest that communicative cues may enhance infants' internal states and promote the development of gaze following. Also, initial social motivation may affect the learning process of social behaviors in the long term.

Transition From Crawling to Walking Changes Gaze Communication Space in Everyday Infant-Parent Interaction

Acquisition of walking changes not only infants' locomotion itself but also infants' exploratory behavior and social interaction, such as gaze communication. To understand the ecological context in which gaze communication occurs and how it changes with walking development from the point of view of the spatial arrangement of infants, parents, and objects, we analyzed longitudinal data of daily eye contact scenes recorded from head-mounted eye trackers worn by parents as infants grew from 10 to 15.5 months, focusing on infant-parent distance and the number of objects between the dyad. A Bayesian state-space model revealed that the interpersonal distance at which infants initiated eye contact with their parents increased with the time ratio of walking to crawling. This result could not be explained by the developmental change in the amount of time that the infants were far from the parents, which is not limited to the gaze communication context. Moreover, the interpersonal distance at which the parents initiated eye contact with the infants did not increase with the time ratio of walking to crawling. The number of objects on the floor between infants and parents at the time of eye contact increased with interpersonal distance. Taken together, these results indicate that the transition from crawling to walking changes the ecological context in which infants initiate gaze communication to a visual environment characterized by a larger interpersonal distance and, therefore, more objects cluttered between the dyad. The present study has wider implications for the developmental change of shared attention in conjunction with walking development.

Effects of attentional behaviours on infant visual preferences and object choice

Many developmental studies have examined the effects of joint attention. However, it has been difficult to compare effects of initiating joint attention and responding to joint attention in infants. Here, we compared the effects of initiating joint attention and responding joint attention on object information processing, object preference, and facial preferences in infants. Thirty-seven infants (10 to 12 months of age) were shown stimuli in which a female gazed towards or away from an object. Participants were assigned to initiating joint attention condition or responding joint attention condition. Results suggest that initiating joint attention promoted object information processing, whereas responding joint attention did not. Both joint attention conditions affected the facial preference for the person who engaged joint attention. In addition, after initiating joint attention, infants chose objects gazed by other person more often than after responding joint attention. It appears that attentional behaviours that precede the perception of certain stimuli affect infants' cognitive responses to those stimuli.