Do infants develop meaningful social preferences among novel individuals based on their social group membership? If so, do these social preferences depend on familiarity on any dimension, or on a more specific focus on particular kinds of categorical information? The present experiments use methods that have previously demonstrated infants' social preferences based on language and accent, and test for infants' and young children's social preferences based on race. In Experiment 1, 10-month-old infants took toys equally from own- and other-race individuals. In Experiment 2, 2.5-year-old children gave toys equally to own- and other-race individuals. When shown the same stimuli in Experiment 3, 5-year-old children, in contrast, expressed explicit social preferences for own-race individuals. Social preferences based on race therefore emerge between 2.5 and 5 years of age and do not affect social choices in infancy. These data will be discussed in relation to prior research finding that infants' social preferences do, however, rely on language: a useful predictor of group or coalition membership in both modern times and humans' evolutionary past. (Contains 2 figures.)