The silent effects of ostracism: how social exclusion modulates behavioral, physiological reactivity and attentional disengagement in 8-month-old infants

Being ostracized -i.e., being excluded and ignored- has been shown to significantly impact psychological well-being (Wesselmann et al., 2016) and physiological activation in adults (Eres et al., 2021). This phenomenon also extends to cognitive processes, such as attentional disengagement from socially salient stimuli (i.e., faces; DeWall et al., 2009). While research has shown that ostracism influences infants' behavioral reactivity (Quadrelli et al., 2023), much remains unknown about how self-experienced ostracism affects social signal processing during infancy and its impact on physiological reactivity. This study explores whether being included or ostracized during a live triadic ball-tossing game impacts 8-month-olds’ behavioral and physiological reactivity during the game, as well as their subsequent attentional disengagement from faces. Infants first engaged in a two-minutes free play interaction with their caregiver before participating in the ball-tossing game, where they were either included or ostracized. During both tasks, we measured infants’ heart rate variability. Following the game, infants completed a disengagement task involving centrally presented neutral and scrambled faces, while their eye movements were recorded using an eye-tracking system. The current sample is composed of twenty-seven 8-month-old infants (N = 13 included and N = 14 ostracized). Preliminary results indicate that ostracized infants exhibit a reduced heart rate variability (rMSSD) as compared to included ones, suggesting increased stress levels. Behavioral reactivity data highlight a decrease in positive emotionality and an increase in active engagement (i.e., asking for the ball, catching the players’ attention). Lastly, eye-tracking data suggest that 8-month-olds are slower to disengage from central stimuli when ostracized vs. when included. Data collection and analysis are still ongoing, however, these preliminary results underline that ostracism affects infants’ physiological and behavioral reactivity but also attentional disengagement from social stimuli from very early in life.