Navigating social affiliation adaptively is a critical task of human life. If parsing the social world into affiliative groups forms a core, generative mechanism of the evolved human mind, even infants may differentiate between minimal depictions of inclusion and exclusion. Furthermore, whether groups include or exclude others may cue their individual value as social partners. If so, infants may expect third-party observers to continue avoiding those others exclude and prefer those they include, further perpetuating discrimination of the already marginalized. Here, we show that 10-18 m.o. infants (n=96) look longer when a neutral observer approaches a novel agent whom an abstract group previously excluded, rather than included, in an animated violation-of-expectation paradigm. We found no effect of participant age. Movements were identical across scenarios, differing only in a delay between the excluded agent and the group. These findings indicate that even infants infer that observed exclusion versus inclusion will generalize to other interactions with new social partners.