In their 2022 study, Thomas and colleagues found that when observing third-party interactions, infants, toddlers, and children might use saliva-sharing as a cue for inferring relationship thickness. The present study is the first external attempt to replicate their key findings with infants aged 8.5 to 10 months (n = 50). We used the original stimuli and the original design, but instead of running the study online and coding gaze direction manually from video recordings, we tested infants in a laboratory and measured gaze behavior with an eye tracker. Our study successfully replicated one of the main findings of the original study (longer looking at the saliva-sharing actress) while failing to replicate the other one (looking first at the saliva-sharer). These findings confirm that infants rely on certain behavioral cues for mapping social relationships among third-party individuals.