Toddlers' sensitivity to dominance traits from faces.

In adults, seeing individual faces is sufficient to trigger dominance evaluations, even when conflict is absent. From early on, infants represent dyadic dominance relations and they can infer conflict outcomes based on a variety of cues. To date, it is unclear if toddlers also make automatic dominance trait evaluations of individual faces. Here we asked if toddlers are sensitive to dominance traits from faces, and whether their sensitivity depends on their face experience. We employed a visual preference paradigm to study 18- and 24-month-old toddlers' sensitivity to dominance traits from three types of faces: artificial, male, female. When presented with artificial faces (Experiment 1), 18- and 24-month-olds attended longer to the non-dominant faces, but only when they were in upright orientation. For real male faces (Experiment 2), toddlers showed equivalent looking durations to the dominant and non-dominant upright faces. However, when looking at female faces (Experiment 3), toddlers displayed a visual preference for the upright non-dominant faces at 24 months. To our knowledge, this is the first study to show that toddlers already display sensitivity to facial cues of dominance from 18 months of age, at least for artificial face stimuli.

The effect of masks on the visual preference for faces in the first year of life.

To prevent the spread of COVID-19, face masks were mandatory in many public spaces around the world. Since faces are the gateway to early social cognition, this raised major concerns about the effect face masks may have on infants' attention to faces as well as on their language and social development. The goal of the present study was to assess how face masks modulate infants' attention to faces over the course of the first year of life. We measured 3, 6, 9, and 12-month-olds' looking behavior using a paired visual preference paradigm under two experimental conditions. First, we tested infants' preference for upright masked or unmasked faces of the same female individual. We found that regardless of age, infants looked equally long at the masked and unmasked faces. Second, we compared infants' attention to an upright masked versus an inverted masked face. Three- and 6-month-olds looked equally long to the masked faces when they were upright or inverted. However, 9- and 12-month-old infants showed a novelty preference for the inverted masked face. Our findings suggest that more experience with faces, including masked faces, leads to efficient adaptations of infants' visual system for processing impoverished social stimuli, such as partially occluded faces.

A norming study of high-quality video clips of pantomimes, emblems, and meaningless gestures.

Recent years have witnessed a growing interest in behavioral and neuroimaging studies on the processing of symbolic communicative gestures, such as pantomimes and emblems, but well-controlled stimuli have been scarce. This study describes a dataset of more than 200 video clips of an actress performing pantomimes (gestures that mimic object-directed/object-use actions; e.g., playing guitar), emblems (conventional gestures; e.g., thumbs up), and meaningless gestures. Gestures were divided into four lists. For each of these four lists, 50 Italian and 50 American raters judged the meaningfulness of the gestures and provided names and descriptions for them. The results of these rating and norming measures are reported separately for the Italian and American raters, offering the first normed set of meaningful and meaningless gestures for experimental studies. The stimuli are available for download via the Figshare database.