Infant temperamental fear, pupil dilation, and gaze aversion from smiling strangers

Abstract

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.

An integrative model of parent‐infant communication development

“…We suggest that the change in infants' ability to communicate using behaviors improves the ability of their caregivers to understand them and affects infants' internal state. A prominent example of the effect of early behavior on infants' internal state is their ability to use gaze aversion in response to social stimuli (Zeng et al., 2022) or during social interaction (Field, 1981) to cope with over‐reactivity (De Schuymer et al., 2012; Zivan et al., 2021); this serves as a primal mechanism of self‐regulation (Rothbart et al., 2011), links internal states, and changes behaviors and autonomic responses (Zivan et al., 2021).…”

“…Even though we do not fully understand the interdependency among the three levels of communication, the supposition is that access to greater self‐regulation capacities enables acting or inhibiting action while sustaining hyper‐ or hypo‐arousal (Blair & Ursache, 2011; Engel & Gunnar, 2020). Decreased contingency with autonomic activity due to infants' growing ability to contain arousal increases while sustaining a stable behavioral output (Blair & Ursache, 2011; Zeng et al., 2022). Schematically depicted in Figure 3, the newly developed symbolic abilities enable infants to self‐regulate and decrease the weight of autonomic signals in altering behavioral output, such as changes in proximity from the parent during dyadic interaction (Rothbart et al., 2011).…”

“…As developmental scientists learn more, this paradigm gradually shifts to include young infants taking active roles in dyadic communication (Filippetti, 2021; Ludwig & Welch, 2022). Technological advancements facilitate the exploration of young infants' perception and communication using autonomic changes in arousal, as an indicator of both perception (Jackson & Sirois, 2009; Zeng et al., 2022) and attention (Rothbart et al., 2011), to study their communicative value (Kret, 2015). These advances allow researchers to surpass behavioral barriers to understand more fully the mechanisms at the base of social interaction (Geva et al., 2017; Wass et al., 2019).…”