Search Results (23)

Infants discriminate faces early in the first year, but research on infants’ discrimination of bodies is plagued by mixed findings. Using a familiarisation novelty preference method, we investigated 7- and 9-month-old infants’ discrimination of body postures presented in upright and inverted orientations, and with and without heads, along with relationships with gross and fine motor development. In our initial studies, 7-month-old infants discriminated upright headless postures with forward-facing and about-facing images. Eye tracking revealed that infants looked at the bodies of the upright headless postures the longest and at the heads of upright whole figures for 60–70% of the time regardless of the presence of faces, suggesting that heads detract attention from bodies. In a more stringent test, with similarly complex limb positions between test items, infants could not discriminate postures. With longer trials, the 7-month-olds demonstrated a familiarity preference for the upright whole figures, and the 9-month-olds demonstrated a novelty preference, albeit with a less robust effect. Unlike previous studies, we found that better gross motor skills were related to the 7-month-olds’ better discrimination of upright headless postures compared to inverted postures. The 9-month-old infants’ lower gross and fine motor skills were associated with a stronger preference for inverted compared to upright whole figures. This is further evidence of a configural representation of bodies in infancy, but it is constrained by an upper bias (heads in upright figures, feet in inverted), the test item similarity, and the trial duration. The measure and type of motor development reveals differential relationships with infants’ representations of bodies. Full article

Simultaneous eye tracking and cerebral hemodynamic monitoring contribute to the understanding of neural responses to stimuli in infants. However, exploring the impact of complex socioeconomic and environmental adversities on neurodevelopment requires transitioning this tool from research laboratories into clinical practice to evaluate its feasibility in outpatient contexts. Background/Objectives: This study aimed to present a protocol for simultaneously integrating functional near-infrared spectroscopy (fNIRS) with eye tracking (ET) in infants at risk for neurodevelopmental disorders in a clinical setting with limited resources, during a cognitive task. Methods:The protocol was applied to infants in their first 12 months of life. The infants were exposed to tasks involving the processing of social and non-social stimuli, while their brain signals were monitored using fNIRS and their eyes were tracked with ET. The protocol included three main stages: (1) pre-collection, involving the preparation and habituation of the infants and equipment setup (fNIRS and ET); (2) cognitive function monitoring, using social and non-social stimuli to assess preferential processing via fNIRS and ET; and (3) post-collection, with guidelines for data pre-processing and analysis. Results: The application of the protocol allowed for the identification of technical challenges and the adaptation of procedures for clinical use. The main methodological challenges were difficulty using the conventional cap, excessive movement, synchronization issues between fNIRS and ET, and difficulties calibrating both devices across different age groups. Conclusions: The standardization proposed in this protocol enables healthcare professionals to explore different neurocognitive aspects in pediatric clinical settings and expands the scope of neurodevelopmental assessments. Full article

Early identification of Autism Spectrum Disorders (ASDs) can significantly improve outcomes. Deficits in joint attention (JA) abilities, considered a milestone in socio-communicative development, are among the earliest indicators of ASD. The purpose of this study is to examine if the ability to disengage visual attention (DA) at 12 months could predict joint attention abilities and socio-communicative development at 24 months in a population of infants at increased likelihood and reduced likelihood to develop ASD. Latency of DA at 12 months was analyzed through an eye-tracking paradigm in a group of 56 infants at increased (IL = 29) or reduced (RL = 27) likelihood to develop ASD. JA at 12 months was assessed through items from the Early Social Communication Scales. Diagnostic status was established at 24 months, with 10 children receiving a diagnosis of ASD. A higher DA latency at 12 months is correlated with a lower frequency of JA behaviors at 12 months and with poorer JA abilities at 24 months. Altered visual attention at 12 months was also correlated with socio-communicative development at 24 months and, together with lower JA abilities at 12 months, correlated with diagnostic status. Our findings point to the potential relevance of DA and JA skills as prognostic markers and intervention targets. Full article

Background: Examining visual behavior during a motor learning paradigm can enhance our understanding of how infants learn motor skills. The aim of this study was to determine if infants who learned a contingency visually anticipated the outcomes of their behavior. Methods: 15 infants (6–9 months of age) participated in a contingency learning paradigm. When an infant produced a right leg movement, a robot provided reinforcement by clapping. Three types of visual gaze events were identified: predictive, reactive, and not looking. An exploratory analysis examined the trends in visual-motor behavior that can be used to inform future questions and practices in contingency learning studies. Results: All classically defined learners visually anticipated robot activation at greater than random chance (W = 21; p = 0.028). Specifically, all but one learners displayed a distribution of gaze timing identified as predictive (skewness: 0.56–2.42) with the median timing preceding robot activation by 0.31 s (range: −0.40–0.18 s). Conclusions: Findings suggest that most learners displayed visual anticipation withing the first minutes of performing the paradigm. Further, the classical definition of learning a contingency paradigm in infants can be sharpened to further the design of contingency learning studies and advance the processes infants use to learn motor skills. Full article

Background: The experimental evaluation of young children’s socio-emotional abilities is limited by the lack of existing specific measures to assess this population and by the relative difficulty for researchers to adapt measures designed for the general population. Methods: This study examined six early social-emotional abilities in 86 typically developing children aged 1 to 3 years using an eye-tracking-based experimental paradigm that combined visual preference tasks adapted from pre-existing infant studies. Objectives: The aim of this study is to obtain developmental norms in six early social-emotional abilities in typical children aged 1 to 3 years that would be promising for an understanding of disorders of mental development. These developmental standards are essential to enable comparative assessments with children with atypical development, such as children with Profound Intellectual and Multiple Disabilities (PIMD). Results: The participants had greater spontaneous visual preferences for biological (vs. non-biological) motion, socially salient (vs. non-social) stimuli, the eye (vs. mouth) area of emotional expressions, angry (vs. happy) faces, and objects of joint attention (vs. non-looked-at ones). Interestingly, although the prosocial (vs. antisocial) scene of the socio-moral task was preferred, both the helper and hinderer characters were equally gazed at. Finally, correlational analyses revealed that performance was neither related to participants’ age nor to each other (dismissing the hypothesis of a common underpinning process). Conclusion: Our revised experimental paradigm is possible in infants aged 1 to 3 years and thus provides additional scientific proof on the direct assessment of these six socio-emotional abilities in this population. Full article

Background: The ability to merge the two retinal images to perceive depth (stereopsis) plays an important role in human vision. Its proper development requires binocular alignment and good visual acuity in both eyes during childhood. Because treatments are more effective when applied early, early diagnosis is important. Unfortunately, assessing stereo deficiencies in infants and young children remains challenging. Recently, it has been shown that ocular-following responses (OFRs; reflexive, short-latency eye movements induced by the sudden motion of a large textured pattern) are sensitive to changes in interocular correlation, making them potentially useful for stereo deficiency assessments. To test this hypothesis, we measured OFRs elicited by dichoptic stimulation in children with normal and compromised stereopsis (due to amblyopia). Methods: Two groups of six children (age- and sex-matched: 3M/3F aged 7–12 yo), one with compromised stereopsis and one with normal stereopsis, were included. OFRs were recorded using a custom high-resolution video eye-tracking system. The relative differences between eye displacement induced by correlated stimuli (up-correlated–down-correlated) and anticorrelated (up-anticorrelated–down-anticorrelated) were compared. Results: We found significant differences between OFRs induced by two dichoptic conditions (correlated and anticorrelated stimuli) in most children with normal stereopsis, whereas no differences were observed in children with compromised stereopsis, indicating a lack of disparity detectors. Conclusions: OFRs might thus be exploited as a diagnostic tool for the objective identification of stereo deficiencies in children. This might lead to improved early diagnosis and treatment outcomes for conditions like amblyopia and strabismus. Full article

Symmetry has long been viewed as a feature of objects that facilitates ease of perception. Three experiments investigated 4- to 5-month-old infants’ detection and processing of vertical symmetry, oblique symmetry, and asymmetry in novel patterns and faces. In Experiment 1, infants showed the fewest shifts in visual fixations to vertical symmetry in patterns and faces, supporting the view that vertical symmetry is processed more efficiently than oblique symmetry or asymmetry. In Experiment 2, stimulus presentation disallowed more than a single visual fixation, and infants looked longer at a face that is vertically symmetrical compared to obliquely symmetrical or asymmetrical, and they looked equally to patterns regardless of symmetry. In Experiment 3, where pattern exposures were prolonged and inverted faces viewed, infants discriminated vertical symmetry in patterns but lost the advantage with vertical symmetry in faces. Thus, symmetry in patterns requires more processing time from infants, and inverting the face costs infants the normal perceptual advantage of symmetry, even though components of the face remain symmetrical. These findings suggest that infants are prepared to exploit symmetry in their everyday perceptual worlds. Full article

Mental rotation is a critically important, early developing spatial skill that is related to other spatial cognitive abilities. Understanding the early development of this skill, however, requires a developmentally appropriate assessment that can be used with infants, toddlers, and young children. We present here a new eye-tracking task that uses a staircase procedure to assess mental rotation in 12-, 24-, and 36-month-old children (N = 41). To ensure that all children understood the task, the session began with training and practice, in which the children learned to fixate which of two houses a giraffe, facing either left or right, would approach. The adaptive two-up, one-down staircase procedure assessed the children’s ability to fixate the correct house when the giraffe was rotated in 30° (up) or 15° (down) increments. The procedure was successful, with most children showing evidence of mental rotation. In addition, the children were less likely to succeed as the angle of rotation increased, and the older children succeeded at higher angles of rotation than the younger children, replicating previous findings with other procedures. The present study contributes a new paradigm that can assess the development of mental rotation in young children and holds promise for yielding insights into individual differences in mental rotation. Full article

Most well-established eye-tracking research paradigms adopt remote systems, which typically feature regular flat screens of limited width. Limitations of current eye-tracking methods over a wide area include calibration, the significant loss of data due to head movements, and the reduction of data quality over the course of an experimental session. Here, we introduced a novel method of tracking gaze and head movements that combines the possibility of investigating a wide field of view and an offline calibration procedure to enhance the accuracy of measurements. A 4-camera Smart Eye Pro system was adapted for infant research to detect gaze movements across 126° of the horizontal meridian. To accurately track this visual area, an online system calibration was combined with a new offline gaze calibration procedure. Results revealed that the proposed system successfully tracked infants’ head and gaze beyond the average screen size. The implementation of an offline calibration procedure improved the validity and spatial accuracy of measures by correcting a systematic top-right error (1.38° mean horizontal error and 1.46° mean vertical error). This approach could be critical for deriving accurate physiological measures from the eye and represents a substantial methodological advance for tracking looking behaviour across both central and peripheral regions. The offline calibration is particularly useful for work with developing populations, such as infants, and for people who may have difficulties in following instructions. Full article

The current study explored the potential influence of infant sleep, measured by parental report and actigraphy, and family functioning on attention development using eye tracking. The use of actigraphy in parallel with parental report, has the advantage of measuring participant’s sleep throughout the night without parental observation and the ability to objectively assess sleep quality. An eye-tracking version of the Gap-Overlap task was used to measure visual attention. Questionnaires and behavioural assessment were used to assess family function, and general cognitive development. Fifty infants (Mean age = 13.44 months, SD = 3.10) participated in the study, 23 of which had full final datasets. Results show that daytime sleep duration, as measured by parental report, and proportion of light sleep at night, as measured by actigraphy, are linked to visual attention. A higher proportion of light sleep, a marker of poorer sleep quality, and less daytime sleep were negatively linked with facilitation and disengagement on the Gap-Overlap task. Family functioning was not associated with attention. The results provide initial evidence that in addition to the amount of daytime sleep; quality of night-time sleep as measured by proportion of light sleep, is a potentially useful sleep variable which requires further focus in the study of attention development. Full article

Eye movement abnormalities in association with cognitive and emotional deficits have been described in neurological, neurodevelopmental, and psychiatric disorders. Eye-Tracking (ET) techniques could therefore enhance cognitive interventions by contingently providing feedback to patients. Since no consensus has been reached thus far on this approach, this study aimed at systematically reviewing the current evidence. This review was performed and reported according to PRISMA guidelines. Records were searched for in PubMed, Web of Science, and Scopus (1990–2021) through the following string: (‘Eye Tracking’ OR ‘Eye-Tracking’ OR ‘Oculomotor’) AND (‘Neuropsychol*’ OR ‘Cognitive’) AND (‘Rehabilitation’ OR ‘Training’ OR ‘Stimulation’). Study outcomes were thematically classified and qualitatively synthesized. A structured quality assessment was performed. A total of 24 articles were included, addressing neurodevelopmental (preterm infants and children with autism spectrum disorder, Rett syndrome, or ADHD; N = 14), psychiatric (mood and anxiety disorders or alcohol dependence; N = 7), and neurological conditions (stroke; N = 3). Overall, ET gaze-contingent training proved to be effective in improving cognitive and emotional alterations. However, population heterogeneity limits the generalizability of results. ET gaze-contingent protocols allow researchers to directly and dynamically train attentional functions; together with the recruitment of implicit, “bottom-up” strategies, these protocols are promising and possibly integrable with traditional cognitive approaches. Full article

We investigated the effect of perinatal dioxin exposure indicated by dioxins in breast milk on children’s gaze behavior. We studied 142 children aged 3 years from the 2012 Bien Hoa birth cohort in a hotspot of dioxin contamination in Vietnam. Children’s faces were viewed using the eye-tracking method. Associations between gaze behavior of faces and neurodevelopmental indices and head circumference were analyzed to determine whether poor gaze behavior indicates increased autistic traits in these children. The gaze fixation duration on facial areas when viewing 10 still images of children was calculated as the gaze behavior index. Autistic behavior was assessed using the Autism Spectrum Rating Scale, and language development was evaluated by the Bayley Scales of Infant and Toddler Development, Ver. 3. The face fixation duration (%) significantly decreased as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) concentrations increased in a dose–effect manner in girls, which suggested atypical gaze behavior for watching human faces. Furthermore, these girls with atypical gaze behavior showed lower social communication scores and smaller head sizes, suggesting increased autistic traits in girls. In conclusion, our findings show sex-specific effects (girls > boys) of perinatal TCDD exposure on gaze behavior in young children. Full article

The association of prenatal phthalate exposure with physical reasoning was assessed in 159 (78 female; 81 male) 4.5-month-old infants from a prospective cohort. Phthalate metabolites were quantified in urine from 16–18 gestational weeks and a pool of five urines from across pregnancy. Infants’ looking times to physically impossible and possible events were recorded via infrared eye-tracking. Infants that recognize that one of the events is impossible will look at that event longer. Associations of phthalate biomarkers with looking time differences (impossible–possible) were adjusted for maternal age, infant sex, and order of event presentation, and effect modification by infant sex was assessed. Each interquartile range (IQR) increase of monoethyl phthalate in the pooled sample was associated with females’ increased looking time (β = 1.0; 95%CI = 0.3, 1.7 s) to the impossible event. However, for males, an IQR increase in monoethyl phthalate at 16–18 weeks (β = −2.5; 95%CI = −4.4,−0.6 s), the sum of di(isononyl) phthalate metabolites in the pooled sample (β = −1.0; 95%CI = −1.8, −0.1 s), and the sum of all phthalate metabolites in both samples (β = −2.3; 95%CI = −4.4, −0.2 s) were associated with increased looking to the possible event, suggesting that higher prenatal phthalate exposure is associated with poorer physical reasoning in male infants. Full article

Research using eye tracking methods has revealed that when viewing faces, between 6 to 10 months of age, infants begin to shift visual attention from the eye region to the mouth region. Moreover, this shift varies with stimulus characteristics and infants’ experience with faces and languages. The current study examined the eye movements of a racially diverse sample of 98 infants between 7.5 and 10.5 months of age as they viewed movies of White and Asian American women reciting a nursery rhyme (the auditory component of the movies was replaced with music to eliminate the influence of the speech on infants’ looking behavior). Using an analytic approach inspired by the multiverse analysis approach, several measures from infants’ eye gaze were examined to identify patterns that were robust across different analyses. Although in general infants preferred the lower regions of the faces, i.e., the region containing the mouth, this preference depended on the stimulus characteristics and was stronger for infants whose typical experience included faces of more races and for infants who were exposed to multiple languages. These results show how we can leverage the richness of eye tracking data with infants to add to our understanding of the factors that influence infants’ visual exploration of faces. Full article

Hypoxic–ischemic injury (HII) at birth has been found to relate to differences in development, including decreased memory performance. The current study assessed recognition memory in 6- and 12-month-old HII infants and typically developing (TD) infants using two eye-tracking paradigms well suited to explore explicit memory processes early in life: visual paired comparison (VPC) and relational memory (RM). During the VPC, infants were familiarized to a face and then tested for their novelty preference immediately and after a two-minute delay. At 6 months, neither HII nor TD showed a VPC novelty preference at immediate delay, but at 12 months, both groups did; after the two-minute delay, no group showed a novelty preference. During RM, infants were presented with blocks containing a learning phase with three different scene–face pairs, and a test phase with one of the three scenes and all three faces appearing simultaneously. When there was no interference from other scene–face pairs between learning and test, 6-month-old TD showed evidence of an early novelty preference, but when there was interference, they revealed an early familiarity preference. For 12-month-old TD, some evidence for a novelty preference during RM was seen regardless of interference. Although HII and TD showed similar recognition memory on the VPC, when looking at RM, HII infants showed subtle differences in their attention to the familiar and novel faces as compared to their TD peers, suggesting that there might be subtle differences in the underlying memory processing mechanisms between HII and TD. More work is needed to understand how these attentional patterns might be predictive of later memory outcomes. Full article