You can't play with us: First-person ostracism affects infants' behavioral reactivity.

Ostracism negatively affects fundamental psychological needs, induces physiological and behavioral changes, and modulates the processing of social information in adults. Yet little is known about children and preverbal infants' responses to first-person experiences of ostracism. The current study aimed to explore the efficacy of a triadic ball-tossing game in manipulating social inclusion and ostracism with 13-month-old infants (N = 84; 44% males; mostly White; tested from 2019 to 2022) by developing an observational coding system. Infants' behaviors were recorded while participating in a ball-tossing game where they were either included or ostracized from the game. Ostracized, but not included, infants showed an increase in negative emotionality and involvement behaviors, thus suggesting that behavioral responses to being ostracized emerge early in life.