Infant Eye Gaze While Viewing Dynamic Faces

First steps into the pupillometry multiverse of developmental science

Pupillometry has been widely implemented to investigate cognitive functioning since infancy. Like most psychophysiological and behavioral measures, it implies hierarchical levels of arbitrariness in preprocessing before statistical data analysis. By means of an illustrative example, we checked the robustness of the results of a familiarization procedure that compared the impact of audiovisual and visual stimuli in 12-month-olds. We adopted a multiverse approach to pupillometry data analysis to explore the role of (1) the preprocessing phase, that is, handling of extreme values, selection of the areas of interest, management of blinks, baseline correction, participant inclusion/exclusion and (2) the modeling structure, that is, the incorporation of smoothers, fixed and random effects structure, in guiding the parameter estimation. The multiverse of analyses shows how the preprocessing steps influenced the regression results, and when visual stimuli plausibly predicted an increase of resource allocation compared with audiovisual stimuli. Importantly, smoothing time in statistical models increased the plausibility of the results compared to those nested models that do not weigh the impact of time. Finally, we share theoretical and methodological tools to move the first steps into (rather than being afraid of) the inherent uncertainty of infant pupillometry.

Infant looking preferences towards dynamic faces: A systematic review

Although the pattern of visual attention towards the region of the eyes is now well-established for infants at an early stage of development, less is known about the extent to which the mouth attracts an infant's attention. Even less is known about the extent to which these specific looking behaviours towards different regions of the talking face (i.e., the eyes or the mouth) may impact on or account for aspects of language development. The aim of the present systematic review is to synthesize and analyse (i) which factors might determine different looking patterns in infants during audio-visual tasks using dynamic faces and (ii) how these patterns have been studied in relation to aspects of the baby's development. Four bibliographic databases were explored, and the records were selected following specified inclusion criteria. The search led to the identification of 19 papers (October 2021). Some studies have tried to clarify the role played by audio-visual support in speech perception and early production based on directly related factors such as the age or language background of the participants, while others have tested the child's competence in terms of linguistic or social skills. Several hypotheses have been advanced to explain the selective attention phenomenon. The results of the selected studies have led to different lines of interpretation. Some suggestions for future research are outlined.

"May I Grab Your Attention?": An Investigation Into Infants' Visual Preferences for Handled Objects Using Lookit as an Online Platform for Data Collection

We examined the relation between 4- to 12-month-old infants' (N = 107) motor development and visual preference for handled or non-handled objects, using Lookit (lookit.mit.edu) as an online tool for data collection. Infants viewed eight pairs of objects, and their looking was recorded using their own webcam. Each pair contained one item with an easily graspable “handle-like” region and one without. Infants' duration of looking at each item was coded from the recordings, allowing us to evaluate their preference for the handled item. In addition, parents reported on their infants' motor behavior in the previous week. Overall, infants looked longer to handled items than non-handled items. Additionally, by examining the duration of infants' individual looks, we show that differences in infants' interest in the handled items varied both by infants' motor level and across the course of the 8-s trials. These findings confirm infant visual preferences can be successfully measured using Lookit and that motor development is related to infants' visual preferences for items with a graspable, handle-like region. The relative roles of age and motor development are discussed.

Bilingual adaptations in early development

Infants raised in bilingual homes redirect attention faster than infants raised in monolingual homes. How can mere exposure to a bilingual environment affect an infant's cognitive development? The more complex language environment may drive infants to explore (gather more information from) their visual environment to facilitate learning.

Infant Eye Gaze While Viewing Dynamic Faces

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.